OBD-II Code U1702: Lost Communication With a Key System

What Does U1702 Mean?

U1702 indicates your car's main computer lost connection with a critical module, most commonly the Electric Power Steering (EPS). When these modules fail to exchange data over the Controller Area Network (CAN bus), the power steering system defaults to a safe mode, disabling steering assistance.

Technical definition: U1702 is a manufacturer-specific code indicating a Controller Area Network (CAN) bus communication failure. Definitions include 'Electric Power Steering (EPS) - Signal Plausibility Failure' (Jeep), 'CAN bus fault between Engine Management ECU and EPS' (Fiat/Alfa Romeo), or 'DTCP Sink Decode error' (Hyundai).

Can I Drive With U1702?

⚠️Yes, But With Caution. You can drive, but we strongly advise against it. This code frequently triggers a total loss of power steering assist, increasing steering effort by 3 to 5 times. This makes the vehicle extremely difficult to control at low speeds, in parking maneuvers, or during an emergency avoidance maneuver. Repair the vehicle immediately.

Common Causes

• Low or Unstable Battery Voltage (Very Common) — Modern cars are extremely sensitive to battery voltage. A weak, old, or dying battery causes random communication codes, including U1702, because the computer modules lack the stable power required to communicate effectively.
• Corroded or Loose Battery Terminals / Ground Straps (Common) — A poor connection at the battery or a corroded main engine-to-chassis ground strap creates electrical resistance and unstable voltage. This electrical 'noise' interrupts communication between modules, triggering the code.
• Blown Main Fuse for the Affected Module (Common) — On many Stellantis (Fiat/Chrysler) vehicles, the Electric Power Steering module is protected by a large, dedicated fuse located directly on the positive battery terminal connector. If this fuse blows, the module loses all power and cannot communicate.
• Control Module Software Glitch (Common) — Manufacturers often release software updates via Technical Service Bulletins (TSBs) to fix communication bugs. This is a heavily documented issue on vehicles like the 2019-2020 Jeep Renegade.
• Damaged Wiring or Loose Connectors (Less Common) — The twisted-pair wires forming the CAN bus network get damaged, corroded, or unplugged. A specific connector known as the 'D4' connector, located near the under-hood fuse box, is a frequent source of this problem on Fiat models.
• Failed Sensor on CAN Bus (Wheel Speed or Yaw Rate) (Less Common) — A failing ABS wheel speed sensor or lateral acceleration sensor sends erratic data to the ABS module. The ABS module broadcasts this bad data on the CAN network, causing the power steering module to log a communication fault, even though the steering hardware is fine.
• Failed Control Module (Rare) — If all wiring, power, grounds, and software are confirmed good, the module itself (like the Electric Power Steering module or the main TIPM computer) has an internal failure.
• Improperly Installed Aftermarket Accessories (Rare) — Aftermarket remote starters, alarms, or stereo systems improperly tapped into the vehicle's CAN bus wiring introduce electrical noise or data conflicts, leading to a flood of communication codes.

Symptoms

• Loss of Power Steering — The steering wheel suddenly becomes very heavy and difficult to turn. This is the most common and noticeable symptom.
• Power Steering Warning Light — A warning light, often shaped like a steering wheel with an exclamation mark, illuminates on your dashboard.
• Multiple Warning Lights — Because this is a network problem, ABS, ESP, or ASR warning lights turn on simultaneously, often accompanied by a 'Loose Connection' message on Fiat models.
• Error Messages on Dash — Your vehicle's information screen displays messages like 'Lane Assist Not Available', 'Check Power Steering', or 'Service Power Steering'.
• Blinking Odometer — On many Fiat, Jeep, and Chrysler vehicles, a blinking odometer indicates a CAN bus communication error. A module on the network is not aligned, requiring a 'Proxy Alignment' procedure.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this code.

Common Fixes & Costs

• Replace Weak or Faulty Battery — Parts: $150-$350, Labor: $50-$100, ~0.5 hr book time (DIY)
• Clean Battery Terminals and Ground Straps — Parts: $5-$15, Labor: $0-$75, ~0.5 hr book time (DIY)
• Power Steering Module Software Update (Flash) — Parts: $0, Labor: $125-$250 (dealer diagnosis/flash fee), ~1 hr book time (Professional)
• Proxy Alignment Procedure — Parts: $0, Labor: $100-$200, ~0.8 hr book time (Professional)
• Repair or Replace TIPM (Main Fuse Box/Computer) — Parts: $300-$650 (for a repaired unit), Labor: $150-$300, ~1.2 hr book time (Intermediate)
• Replace Electric Power Steering Rack Assembly — Parts: $1200-$2000, Labor: $400-$700, ~4.5 hr book time (Professional)

Used vs. New Parts: Buying Guide

When a used part is worth it: A used or remanufactured Electric Power Steering (EPS) rack is a viable option when the vehicle is older (over 8 years), out of warranty, and budget is the primary concern. They cost 30-50% less than a new OEM part.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Match the part number exactly; electronic modules are not interchangeable.
• Buy from a reputable rebuilder or a salvage yard that offers a warranty (30-90 days is typical).
• Ensure the unit has been tested and is guaranteed functional.
• Avoid parts from vehicles with flood damage or major front-end collisions.

Decision logic:

• If The fix is a known software bug (like on a Jeep Renegade) → Do not buy any part; pay for the dealer software update first.
• If Vehicle is less than 5 years old or has low mileage → Buy a new OEM part for the longest lifespan and best warranty.
• If Vehicle is over 10 years old and the budget is tight → A warrantied remanufactured unit offers the best balance of cost and reliability.

Warranty tradeoff: Used/salvage parts often have a 30-90 day part-only warranty. Remanufactured parts typically offer a 1-year to limited lifetime warranty, but do not cover labor. A new OEM part installed by a dealer carries a 1-2 year warranty on both parts and labor.

Worst-case if a used part fails: $500-$1000 if a used/reman part fails. This includes the cost of repeat labor to remove and replace the faulty unit, plus a second wheel alignment.

What Happens If You Wait — Timeline

1. 0-4 weeks: Intermittent power steering failure. The warning light comes on and steering becomes heavy, but turning the car off and on again temporarily restores function. The U1702 code is stored. (MPG impact: 0%% · Added cost: $0)
2. 1-3 months: Failures become more frequent. If the cause is a weak battery or alternator, you notice dimming headlights, slow engine cranking, or other random electronic glitches. The power steering fails on most drives. (MPG impact: 0-1%% · Added cost: $0-$50 in diagnostic fees or wasted time.)
3. 3-6 months: Permanent loss of power steering assist. The warning light is always on. If the root cause is a failing battery or alternator, it struggles to start the car. The vehicle is consistently unsafe to drive. (MPG impact: 0-2%% · Added cost: $200-$800 (Cost to replace the underlying electrical fault, like a battery or alternator, which has now failed completely).)
4. 6+ months: Catastrophic failure. Driving with a severe electrical issue stresses other modules. If the root cause was a software glitch that was ignored, the owner mistakenly pays for an unnecessary steering rack replacement. Worst case: a complete no-start or a fried TIPM/BCM. (MPG impact: N/A (Vehicle may not be drivable)% · Added cost: $1600-$2700+ (Cost of misdiagnosing the issue and replacing the entire steering rack assembly or another major control module).)

Cost of Not Fixing It

• Immediate: Sudden loss of power steering assist creates a significant safety hazard. The steering wheel becomes extremely difficult to turn, increasing the risk of an accident. (Added cost: $0 (Safety Risk))
• Short-Term (Days to Weeks): Continued driving with an unstable electrical system stresses other electronic modules. Intermittent power steering function becomes more frequent. (Added cost: Negligible)
• Long-Term (Months): If the root cause is a failing alternator or battery, it eventually leads to a no-start condition. Ignoring a communication problem masks other developing issues on the CAN network. (Added cost: $200-$800 (for a new battery and/or alternator replacement))

Diagnosis Steps

1. Check Battery Health First
   Before any other action, verify the battery's health. Use a multimeter to ensure it has at least 12.4 volts with the engine off and over 13.5 volts with the engine running. Have it professionally load-tested at an auto parts store to confirm it is healthy under load, as low voltage is the #1 cause of network faults.
   Tools: Multimeter, Battery Tester (Beginner)
2. Scan for Related Codes in ALL Modules
   Use a quality OBD-II scanner to read manufacturer-specific codes from all modules (ABS, BCM, etc.). Look for other 'U' or 'C' codes appearing alongside U1702. On a Jeep Renegade, U1702 pairs with C1013-49. On an Alfa Romeo, it appears with C0051 (Steering Angle Sensor).
   Tools: Advanced OBD-II Scanner (Intermediate)
3. Inspect Terminals, Fuses, and Grounds
   Clean corrosion from the battery terminals and clamps. Inspect the main engine-to-chassis and battery-to-chassis ground straps to ensure they are tight and unbroken. On Stellantis vehicles, inspect the large mega-fuse block mounted directly on the positive battery terminal for blown EPS fuses.
   Tools: Wrench Set, Wire Brush (Beginner)
4. Check for Technical Service Bulletins (TSBs)
   Search online for TSBs related to your vehicle's make, model, year, and the U1702 code. A TSB points to a known software bug requiring a dealer reflash, which is a much cheaper fix than replacing hardware.
   Tools: Internet Access (Intermediate)
5. Inspect Known Problem Connectors
   Visually inspect the wiring harness going to the power steering rack. On Fiat models (Stilo, Bravo, Punto), disconnect the 'D4' connector near the under-hood fuse box, check for corrosion or bent pins, and clean with electrical contact cleaner.
   Tools: Flashlight, Electrical Contact Cleaner (Advanced)
6. [PRO TIP] Monitor Module Status with a Scan Tool
   Access the live data for the Body Control Module (BCM) or Gateway Module using an advanced scan tool. View the list of all modules on the network to see which are actively communicating and which are 'offline'. This instantly confirms if the EPS module is unresponsive.
   Tools: Advanced OBD-II Scanner (Advanced)
7. [PRO TIP] Check CAN Bus Voltages at the OBD-II Port
   Set a multimeter to DC Volts. Connect the black probe to chassis ground (pin 4 or 5). With the ignition ON (engine off), probe pin 6 (CAN High). You should see 2.5V to 3.5V. Probe pin 14 (CAN Low); you should see 1.5V to 2.5V. The two voltages must be mirror opposites and add up to approximately 5V. A reading of 0V, 5V, or 12V indicates a short circuit.
   Tools: Multimeter (Advanced)
8. [PRO TIP] Check CAN Bus Termination Resistance
   Turn the ignition OFF and disconnect the battery. Measure resistance (Ohms) between pin 6 (CAN High) and pin 14 (CAN Low) at the OBD-II port. A healthy CAN bus reads approximately 60 Ω. A reading of 120 Ω means a terminating resistor is missing or the circuit is open. A reading near 0 Ω indicates the CAN wires are shorted together.
   Tools: Multimeter (Advanced)
9. [PRO TIP] Check for Shorts to Power/Ground
   With the battery disconnected, check resistance between CAN High (Pin 6) and chassis ground (Pin 4/5), and CAN Low (Pin 14) and chassis ground. Both must read infinite resistance (OL). Check resistance between CAN High (Pin 6) and battery power (Pin 16), and CAN Low (Pin 14) and battery power. Both must read infinite resistance. Any continuity indicates a short.
   Tools: Multimeter (Advanced)

When This Code Triggers (Freeze-Frame Conditions)

• Battery Voltage: 11.5-12.2V (During engine crank or immediately after, when voltage is lowest)
• Vehicle Speed: 0 mph (Fault often sets at key-on before the engine starts)
• RPM: 0 or >1500 (Either at startup or during steady-state driving when a voltage dip occurs)
• Time Since Engine Start: 0-10 seconds (The communication check fails during the initial module 'handshake')

Related Codes

• C1013-49 — On Jeep vehicles, this means 'Internal Electronic Failure' in the power steering module. U1702 is the main computer's view of the problem, while C1013-49 is the module's own confession. They almost always appear together and point to the same software glitch.
• U1700 — This means 'Lost Communication with Body Control Module (BCM)'. Seeing U1700 alongside U1702 proves the problem is not isolated to the power steering. This combination points to a systemic issue like low battery voltage or a bad main ground.
• U0001 — This is a generic code for 'High Speed CAN Communication Bus'. It means the entire network is compromised. This strongly suggests a major wiring harness short or a gateway module failure that took the whole network down.
• C0051 — This code relates to the Steering Angle Sensor (SAS). A failing SAS sends erratic data, which the power steering module interprets as a communication fault, triggering U1702. If C0051 is present, the SAS is the primary suspect.

Climate & Environmental Factors

• Moisture and Humidity: Water intrudes into connectors (like the Fiat D4 connector), the EPS motor housing, or the control module itself, causing corrosion and short circuits. This is a leading cause of intermittent failure in rainy climates.
• Extreme Cold: Low temperatures cause electrical components to respond slowly, triggering communication faults. On some FCA vehicles, extreme cold links to specific software glitches causing high steering effort.
• Extreme Heat: High ambient temperatures combined with prolonged operation (like frequent parking maneuvers) cause the EPS electric motor to overheat. This triggers a thermal protection mode, shutting down power assist and logging communication faults.

How to Talk to a Mechanic About This Code

Say this: "I have a U1702 code and a loss of power steering. I'd like to book a diagnostic appointment. Based on my research, the most common causes are the battery, grounds, main fuses, or a software update. I'd like you to start by load-testing the battery and checking main power/ground connections before looking at more expensive parts."

This signals you are an informed consumer and guides the technician down the most logical and cost-effective diagnostic path. It prevents them from immediately quoting an expensive steering rack replacement and focuses them on the basics first.

Avoid saying:

• 'My steering is heavy, fix it.'
• 'My check engine light is on, can you just look at it?'
• 'I think I need a new power steering rack.'

Questions to ask before authorizing the repair:

• Did you load-test the battery, or just check the voltage? What were the results?
• Have you inspected the main chassis ground straps and the fuses on the battery terminal?
• Did you check for any Technical Service Bulletins (TSBs) related to this code for my vehicle's VIN?
• If a Proxy Alignment is needed, do you have the equipment to perform it here?
• Can you show me the corroded connector or the bad reading on the multimeter before we replace the part?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Necessary for specific TSB software updates. A good second choice if a trusted independent specialist isn't available.
  Best for: Vehicles under warranty., Confirmed software issues requiring a TSB flash (e.g., 2019-2020 Jeep Renegade)., Complex Proxy Alignment procedures if an independent shop is not equipped.
  Downsides: Highest labor rates, often 1.5-2x more than independent shops., Defaults to replacing expensive modules rather than diagnosing simpler wiring or connection issues. (Typical cost: +50% vs. baseline)
• Independent Shop: Best fit for most scenarios, especially for Fiat/Alfa Romeo. Find a well-reviewed shop with experience in electrical diagnostics. Ask if they are comfortable with CAN bus issues.
  Best for: Out-of-warranty vehicles where cost is a factor., Diagnosing common electrical faults like bad batteries, grounds, and fuses., Shops specializing in your vehicle's brand (e.g., a European specialist for Fiat/Alfa Romeo) are often equipped for advanced diagnostics like Proxy Alignment.
  Downsides: Quality and equipment vary widely; vet the shop's reputation and ask if they handle complex electrical/network diagnostics., Lacks access to the very latest TSB information or OEM flashing tools. (Typical cost: +0% vs. baseline)
• Chain Shop: AVOID for initial diagnosis. Only use for a simple battery replacement after you have confirmed it is the root cause.
  Best for: Simple, clear-cut parts replacement like batteries or terminals if you've already diagnosed the issue yourself.
  Downsides: Not equipped or trained for complex network diagnostics like U1702., High pressure to upsell unnecessary services; misdiagnoses the issue and recommends expensive, incorrect parts. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost, especially for a worst-case scenario like a steering rack replacement, exceeds 50% of your car's private-party value, you should pause and reconsider.

• Car worth $5000, fix is $2500: Borderline. The repair cost is 50% of the car's value. Get a second opinion to ensure the diagnosis is correct before authorizing such an expensive repair.
• Car worth $15000, fix is $2500: Fix it. The repair is well below the 50% threshold and makes economic sense.
• Car worth $3000, fix is $2500: Walk away. The repair cost is over 80% of the car's value. It is not economically viable.

What Scan Tool You Need for This Code

Minimum: A scanner that reads manufacturer-specific codes (like 'U' and 'C' codes) from ALL vehicle modules, including the BCM, ABS, and EPS. A generic code reader that only sees 'P' codes from the engine is not sufficient.

A basic $20 scanner will not see the U1702 code at all, or it fails to scan the other modules to find related codes (like C1013 or C0051) that are critical for diagnosis. You will be flying blind and waste money on incorrect repairs.

Budget: BlueDriver Pro (~$100) — Reads and clears enhanced codes from all modules (ABS, Airbag, BCM, etc.) on most major brands. It allows you to see the full picture of what codes are stored across the network, which is the essential first step.

Mid-range: Foxwell NT510 Elite / MultiECUScan (~$150-250) — The Foxwell NT510 Elite offers bi-directional controls to test components. For Stellantis vehicles, the MultiECUScan software (around $60) paired with a compatible ELM327 interface and adapter cables is the gold standard for DIY, as it performs the critical 'Proxy Alignment' procedure.

Professional: Autel MaxiCOM MK808 / MK808BT (~$450-600) — Offers full-system, OE-level diagnostics with bi-directional control to command modules directly. It performs Proxy Alignments on FCA vehicles and many other service functions, making it a powerful tool for diagnosing complex network issues.

Rent vs buy: For U1702, a basic rental scanner from an auto parts store is insufficient. If you own a Stellantis product, buying MultiECUScan is a very cost-effective investment. For other brands, a mid-range scanner like the Foxwell or Autel is a wise purchase for any DIYer tackling modern electronic issues.

How to Clear the Code After You Fix It

1. Ensure the battery is fully charged and connections are tight.
2. Use a compatible OBD-II scan tool to clear the U1702 code from all modules.
3. For Stellantis vehicles, perform a 'Proxy Alignment' if the odometer is blinking or a module was replaced.
4. Perform at least one full drive cycle to allow the system to verify the fix.

Drive cycle (~20 minutes): Cold start the vehicle and let it idle for 2-3 minutes. Drive in stop-and-go city traffic for about 10 minutes, including several full stops. Drive for 5-10 minutes at a steady highway speed (55+ mph). Let the vehicle cool down completely. The warning light for the power steering should remain off.

Readiness monitors affected: Comprehensive Component Monitor, Misfire Monitor

Before emissions retest: drive at least 50 miles to fully set monitors.

Watch out for:

• Simply disconnecting the battery will not clear the fault from memory in most modern cars and causes other issues.
• The code returns immediately if the underlying electrical or communication problem has not been corrected.
• Using a basic code reader that only clears generic ECU codes will not clear the fault from the Body Control Module or Power Steering Module.

Will This Fail Emissions / State Inspection?

Yes — this code typically fails an OBD-II emissions inspection.

• California: An illuminated warning light due to a 'U' code is an automatic failure of the smog check. All readiness monitors must be set to 'Ready', which is impossible until the fault is cleared and a drive cycle is completed.
• New York: The NYS inspection includes an OBD-II scan. Any active diagnostic trouble code that turns on a warning light, including U1702, causes the vehicle to fail the inspection.
• Texas: For vehicles in the 17 counties requiring emissions testing, an active U1702 code with an illuminated malfunction light causes an automatic failure of the OBD portion of the test.

Most Commonly Affected Vehicles

• Jeep Renegade (2019-2020) — A well-documented software issue causes U1702 and C1013-49 to set together. The primary fix is a dealer software update per TSB 08-041-20 before any hardware is replaced.
• Fiat Stilo (2001-2010) — Prone to CAN bus communication faults between the engine and power steering ECUs. The most common cause is a poor connection at the 'D4' connector next to the engine bay fuse box.
• Fiat Bravo (2007-2014) — Often experiences loss of power steering with code U1702 due to a blown main fuse on the positive battery terminal or disturbed wiring after engine bay repairs.
• Ford Ka (Gen 2) (2008-2016) — Built on the Fiat 500 platform and shares its entire electrical architecture. It suffers from the exact same U1702 and power steering faults common to Fiat vehicles.
• Chevrolet / GM Various (2010-2024) — Many GM vehicles present identical symptoms (loss of power steering with network codes) caused by a faulty ABS wheel speed sensor or Steering Wheel Position Sensor sending bad data across the CAN bus.
• Alfa Romeo Giulietta (2010-2020) — Shares a similar platform with Fiat models and suffers from the same U1702 'Missing Message' fault from the EPS module, often accompanied by a C0051 steering angle sensor code.
• Fiat 500 / Punto (2007-2024) — A weak battery is a very common cause for triggering a U1702 code and power steering failure due to the high electrical demand of the EPS system.
• Hyundai Genesis (BH) (2012-2014) — Uniquely, U1702 does not relate to power steering on this vehicle. It indicates a 'DTCP Sink Decode error' within the Audio/Video/Navigation head unit.

Manufacturer-Specific Notes

• Jeep/Chrysler/Dodge (Stellantis): U1702 is often caused by a software bug. TSB 08-041-20 for the 2019 Jeep Renegade explicitly states that codes U1702 and C1013-49 are fixed with a software update. Always check for a TSB before replacing expensive parts.
• Fiat/Alfa Romeo: U1702 is very frequently caused by a poor physical connection. Technicians first check the 'D4' wiring connector near the fuse box, the main ground straps, and the large mega-fuse on the battery terminal.
• General Motors (Chevrolet, GMC, etc.): A loss of assist accompanied by communication codes is frequently caused by a faulty ABS wheel speed sensor or steering angle sensor, not the steering rack itself. Scan the ABS and BCM modules before condemning the EPS unit.
• Hyundai: Unlike most brands, U1702 on certain Hyundai models (like the 2012 Genesis) has nothing to do with steering. It points to a digital media copyright error in the navigation and audio head unit.

Real Owner Stories

2019 Jeep Renegade with multiple warning lights

Owner experienced a 'Christmas light' effect on the dash with seven error codes appearing at once, including for ABS and power steering. The vehicle was drivable but had no power assist.

What they tried:

1. A mechanic initially suspected a bad ABS sensor, but a computer scan showed all four sensors were registering correctly.
2. Based on forum advice suggesting battery issues are common, the owner replaced the original Mopar battery.

Outcome: Replacing the battery immediately cleared all warning lights and error codes. The problem did not return. The total cost was about $360 CAD for a new, higher CCA battery.

Lesson: On modern Jeeps, a weak battery causes a cascade of seemingly unrelated electronic faults. Even if the battery's voltage appears normal, it fails to provide stable power for all modules. Replacing the battery is a critical first step.

2007 Fiat Bravo with U1702 after a major repair

After having the gearbox replaced, which involved disconnecting the battery for a week, the car started but had no power steering and a U1702 code.

What they tried:

1. The owner checked all ground connections, which appeared fine.
2. Suspecting a failed power steering motor, they purchased a replacement steering column assembly.
3. Before installing the expensive new part, they discovered the actual cause.

Outcome: The problem was a blown main fuse located directly on the positive battery terminal connector. This simple, inexpensive part failed when the battery was reconnected. Replacing the fuse restored power steering function completely.

Lesson: Always check large-amperage 'mega fuses' on or near the battery terminal, especially after the battery has been disconnected for other service. This is a common failure point on Stellantis vehicles.

Fiat Stilo with intermittent 'Loose Connection' errors and U1702

The vehicle intermittently displayed 'Loose Connection', 'ASR', 'ESP', and 'ABS' errors, sometimes causing the engine to cut out. Eventually, the power steering failed permanently, logging a U1702 code.

What they tried:

1. The owner first suspected a bad battery or alternator, but both tested good.
2. They disassembled and cleaned the engine bay fuse box, which temporarily changed the error code from U1601 to U1702.
3. Following advice from a Fiat forum, they located and inspected the 'D4' connector.

Outcome: The infamous 'D4' connector, located in the battery box, was the culprit. Cleaning the connector pins and ensuring a secure connection resolved all communication errors and restored power steering.

Lesson: On Fiat Stilo and related platforms, the D4 connector is a notorious weak point. Intermittent, multi-system electrical faults are a classic symptom of a problem at this specific connector.

2016 Jeep Renegade 1.4L with sudden power steering loss and no-shut-off condition

While driving, numerous warning lights appeared, the power steering failed, and critically, the engine and electronics would not turn off even with the key removed. The owner had to pull the fuel pump fuse to shut the car down.

What they tried:

1. Researching online, the owner found a few other cases describing the exact same sequence of bizarre failures.
2. One mechanic was hesitant to perform the repair, believing a new key would need to be programmed by the dealer.

Outcome: A local Jeep specialist diagnosed and replaced the ignition switch. This single component failure was responsible for all the symptoms, including the power steering loss and the inability to turn the vehicle off.

Lesson: A failing ignition switch causes a cascade of strange electrical issues that mimic a major CAN bus or module failure. If you experience a loss of power steering combined with the inability to shut off the engine, the ignition switch is a primary suspect.

How to Prevent This Code From Triggering

• Periodically clean battery terminals and chassis ground points (Every 12 months or during oil changes) — Prevents corrosion buildup which creates electrical resistance and unstable voltage, a primary cause of CAN bus communication errors like U1702.
• Replace vehicle battery every 3-5 years, regardless of symptoms (Once per 3-5 years) — Modern cars are highly sensitive to voltage. An aging battery fails to provide the stable, clean power required by networked modules, leading to random communication faults.
• Use a battery tender or maintainer if the vehicle is stored or driven infrequently (During any storage period longer than 2-3 weeks) — Prevents the battery from slowly discharging to a point where voltage becomes too low to support module communication on startup.
• Ensure battery cover and all engine bay seals are intact (Check during routine fluid checks) — Protects critical connectors (like the Fiat D4), fuse boxes, and module housings from moisture intrusion, which leads to corrosion and short circuits.
• Avoid installing aftermarket electronics that tap into the CAN bus (During vehicle ownership) — Improperly installed accessories introduce electrical noise or data conflicts onto the network, causing a flood of communication codes.

Frequently Asked Questions

Can I fix U1702 myself?

You can perform basic checks like testing the battery, cleaning terminals, and inspecting fuses. However, software updates, proxy alignments, or replacing the steering rack require professional tools. Stop DIYing and visit a shop if basic electrical tests pass.

What are the most common misdiagnosis mistakes for U1702?

The biggest mistake is immediately replacing the expensive electric power steering rack. Always rule out simpler causes first, such as a weak battery, corroded grounds, or blown fuses. Failing to check for manufacturer TSBs or scanning all modules also leads to unnecessary part replacements.

Is it safe to drive with a U1702 code?

No. The primary risk is a sudden and complete loss of power steering. This makes the car extremely difficult to control, especially when parking or in an emergency.

Will clearing the code make it go away?

Clearing the code with a scanner temporarily turns off the warning light. However, if an underlying hardware or software problem exists, the code and symptoms will return quickly. You must fix the root cause for a permanent solution.

My power steering works sometimes and fails other times. Could it still be U1702?

Yes, intermittent failure is a classic symptom of a developing problem like a loose connection, failing module, or unstable battery voltage. The problem will become more frequent over time until it fails permanently.

My U1702 code appeared right after a different repair. Are they related?

Yes, they are highly likely related. Disconnecting the battery causes voltage spikes or requires a 'proxy alignment' to re-establish communication. Engine bay work can also inadvertently disturb a critical ground wire or wiring harness.

Why did my power steering fail right after I disconnected the battery?

Disconnecting the battery causes a voltage surge or drop that triggers a fault in the sensitive power steering module. On Stellantis vehicles, this often causes modules to lose their network configuration. You will likely need a 'Proxy Alignment' procedure with a dealer-level scan tool to fix it.

What is a proxy alignment and do I need one for U1702?

A Proxy Alignment is a diagnostic procedure used on Stellantis vehicles to sync all computer modules on the CAN network. If a module is replaced or loses communication, the network configuration breaks, often indicated by a blinking odometer. You need this procedure after fixing a U1702 code to restore full communication.

Can a bad alternator cause a U1702 code?

Yes. A failing alternator produces unstable voltage and electrical noise. Computer modules rely on steady, clean voltage to communicate over the CAN network. Erratic voltage easily corrupts these signals and triggers communication faults.

Key Takeaways

• Code U1702 indicates a critical computer module, usually the Electric Power Steering (EPS), has stopped communicating over the CAN bus network.
• Test your battery first; a voltage drop below 12.4V is the number one cause of this communication failure.
• For 2019-2020 Jeep Renegades, do not replace hardware; TSB 08-041-20 specifies a $125-$250 dealer software update to fix this code.
• On Fiat and Alfa Romeo models, inspect the 'D4' wiring connector and the 70-amp mega-fuse on the positive battery terminal before buying new parts.