OBD-II Code U0425: Invalid Data Received From Auxiliary Heater Control Module

What Does U0425 Mean?

The U0425 code triggers when the Powertrain Control Module (PCM) receives corrupted, malformed, or out-of-range data from the auxiliary heater control module. This separate module manages supplemental electric (PTC) or fuel-fired heaters designed to warm the cabin or diesel exhaust fluid (DEF) faster. When the PCM detects irrational data packets, it logs the error and disables the heater to protect the network.

Technical definition: Invalid Data Received From Auxiliary Heater Control Module

Can I Drive With U0425?

⚠️Yes, But With Caution. Yes, but your cabin heating or diesel DEF heater will fail. The primary risk is a parasitic battery drain; a malfunctioning module fails to enter sleep mode, killing your battery overnight. This requires a jump-start or a $150-$400 battery replacement. Rarely, a faulty module broadcasts corrupt data across the CAN bus, causing erratic behavior in unrelated safety or drivability systems.

Common Causes

• Faulty Auxiliary Heater Control Module (Very Common) — The module itself is the most frequent culprit. Internal components like microcontrollers, driver circuits, or solder joints fail from age, vibration, or thermal cycling, causing the unit to broadcast corrupt data.
• Low or Unstable Power Supply (Common) — The auxiliary heater module requires a stable 12-volt power supply and a solid ground. A weak battery, failing alternator, or bad ground drops voltage below 10V during startup, triggering module resets and malformed data packets.
• Corrupted Software or Firmware Mismatch (Common) — If the module's software is outdated or doesn't match the PCM's expected parameters, the data registers as invalid. Manufacturers frequently issue Technical Service Bulletins (TSBs) to resolve this with a software reflash.
• Wiring Harness or Connector Issues (Common) — The wires and connectors linking the module to the CAN bus network corrode, chafe, or loosen. This physical damage interrupts the signal, introduces high resistance, and causes data packet errors.
• Water Intrusion (Less Common) — Modules located under the cowl, near the firewall, or under the vehicle (like DEF heaters) are prone to moisture. Water leaks cause rapid corrosion on connector pins and internal circuit boards, shorting the data lines.
• CAN Bus Network Fault (Rare) — Interference from another failing module on the vehicle's network corrupts the data from the auxiliary heater module. This is a network-level problem where a completely different module 'shouts' over the others.

Symptoms

• Check Engine Light is On — The Malfunction Indicator Lamp (MIL) illuminates immediately after the PCM detects the invalid data.
• Auxiliary Heater Fails to Activate — The supplemental heater stays off, resulting in delayed cabin heat or a frozen DEF system in diesel trucks during cold weather.
• Parasitic Battery Drain — The faulty module fails to enter 'sleep' mode when the ignition is off, draining a healthy battery completely overnight.
• Climate Control Warning Message — The instrument cluster displays a specific warning message like 'Aux Heater Fault' or 'Service Emission System' (on diesels).
• Unpredictable Climate Control Behavior — The HVAC system behaves erratically, ignoring temperature settings or fluctuating fan speeds.

Diagnostic Flowchart

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

Common Fixes & Costs

• Replacing the Auxiliary Heater Control Module — Parts: $250-$800, Labor: $150-$350, ~2 hr book time (Professional)
• Reprogramming/Reflashing the Control Module — Parts: $0, Labor: $150-$300, ~1.5 hr book time (Professional)
• Repairing Wiring or Connectors — Parts: $10-$50, Labor: $120-$250, ~1.5 hr book time (Intermediate)
• Replacing a Faulty Battery or Repairing Ground Connection — Parts: $150-$300, Labor: $0-$100, ~0.5 hr book time (DIY)
• Replacing a Blown Fuse — Parts: $1-$10, Labor: $0-$50, ~0.1 hr book time (DIY)

DIY vs Professional

• Replacing a Blown Fuse / Faulty Battery 🟢 Beginner
  Tools: Fuse puller, basic socket set.
• Repairing Wiring or Connectors 🟢 Beginner
  Tools: Multimeter, wire strippers, crimpers, heat gun, wiring diagrams.
• Replacing the Auxiliary Heater Control Module 🟢 Beginner
  Tools: Socket set, trim tools, professional OBD-II scanner with J2534 programming capabilities.
• Reprogramming/Reflashing the Control Module 🟢 Beginner
  Tools: Manufacturer diagnostic software, J2534 Pass-Thru device, stable 100A battery maintainer.

Used vs. New Parts: Buying Guide

When a used part is worth it: A used module makes sense only for vehicles over 10 years old where the part is plug-and-play (no VIN programming required) and budget is strictly limited.

Donor-vehicle mileage cap: roughly under 100000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Verify the part number matches EXACTLY. Modules are highly specific to trim levels.
• Buy from a reputable auto recycler offering a minimum 30-day warranty.
• Visually inspect the module for corrosion, water damage, or burnt connector pins.
• Avoid parts from flood-damaged or fire-damaged donor vehicles.

Decision logic:

• If Vehicle is less than 10 years old OR the part requires complex VIN programming → Buy new or professionally refurbished. The risk of incompatibility with a used part is too high.
• If Vehicle is over 10 years old AND the part is a simple 'plug-and-play' module → A used part from a low-mileage donor is a reasonable choice.
• If A Technical Service Bulletin (TSB) exists for a software update → Do not buy any part; pursue the software reflash at a dealer first.

Warranty tradeoff: Used parts carry a 30-90 day warranty covering only the part. New aftermarket parts offer 1-year warranties. New OEM parts carry a 1-2 year warranty, honored only if installed by a dealer.

Worst-case if a used part fails: $300-$700 if a used module fails, requiring repeat labor costs for diagnosis, programming, and a second replacement part.

What Happens If You Wait — Timeline

1. 0-1 month: Code is set, Check Engine Light illuminates. Auxiliary cabin heater fails, resulting in slower cabin warming. No drivability symptoms. (MPG impact: 0%% · Added cost: $0)
2. 1-3 months: The faulty module fails to enter 'sleep' mode, creating a parasitic battery drain. This leads to a dead battery and a no-start situation. (MPG impact: 0%% · Added cost: $150-$400 (for a new battery and jump-start service))
3. 1-6 months (Diesel trucks in cold climates): The DEF fluid freezes. The truck displays a 'Service Emission System' warning and begins a mileage countdown before entering a 5 mph limp mode. (MPG impact: 0%% · Added cost: $200-$1000 (for towing, lost productivity, and repair))
4. 6+ months (Rare): A module sending continuous corrupt data interferes with other modules on the CAN bus, causing erratic symptoms in ABS, stability control, or the instrument cluster. (MPG impact: 0-2%% · Added cost: $500-$2500+ (for advanced network diagnostics))

Cost of Not Fixing It

• Immediate: No auxiliary cabin heat. For diesel trucks, the DEF heater fails, risking DEF fluid freezing and triggering emission warnings. (Added cost: $0)
• 1-4 weeks: The malfunctioning module fails to enter sleep mode, causing a parasitic battery drain. This leads to a dead battery and a no-start condition. (Added cost: $150-$400 (for battery replacement and labor))
• 1-6 months (Diesel Trucks in Cold Climates): If the DEF fluid freezes, the truck enters a speed-limited 'limp mode' (max 50 mph, then 5 mph) and eventually refuses to start. (Added cost: $200-$1000+ (for towing, lost work, and eventual repair))
• Long-term (Rare): A module sending continuous corrupt data disrupts the entire CAN bus network, causing critical systems like ABS or stability control to malfunction. (Added cost: $500-$2500+ (for complex network diagnostics))

Diagnosis Steps

1. Scan for Codes and Review Live Data
   Use a professional OBD-II scanner to confirm U0425. Check for other communication (U-prefix) codes, which point to a wider network issue. Review live data from the auxiliary heater module to see the exact values it reports.
   Tools: Professional OBD-II Scanner (Beginner)
2. Perform a Comprehensive Battery Test
   Verify the battery is fully charged and the alternator works correctly. Low voltage is a primary cause of communication errors. A healthy system shows ~12.6V with the engine off and ~13.7-14.7V while running.
   Tools: Multimeter, Automotive Battery Tester (Beginner)
3. Check for Technical Service Bulletins (TSBs)
   Search for TSBs related to your specific VIN and the U0425 code. Manufacturers often release software updates to fix communication glitches. A dealer reflash is frequently the only required fix.
   Tools: Access to TSB database (Alldata, ProDemand, or NHTSA) (Beginner)
4. Inspect the Wiring and Connectors
   Visually inspect the wiring harness and electrical connector at the auxiliary heater control module. Look for corrosion, moisture, loose pins, or chafing. Gently tug the wires to ensure they are seated securely.
   Tools: Flashlight, Trim removal tools (Intermediate)
5. Test Power and Ground at the Module
   Using a multimeter and a wiring diagram, verify the module receives battery voltage (~12V) and has a solid ground. Resistance to a known good chassis ground must be less than 0.1 ohms. Stop DIY and go to a shop if these checks pass but the code remains.
   Tools: Multimeter, Vehicle-specific wiring diagram (Intermediate)
6. [PRO TIP] Monitor Live Data PIDs for Heater Function
   Using a bidirectional scanner, access the live data stream for the auxiliary heater module. Command the heater 'On' and 'Off'. A healthy system shows the status change, current draw (several amps), and a temperature rise. Illogical values confirm a module failure.
   Tools: Professional Bidirectional Scanner (Advanced)
7. [PRO TIP] Isolate the Module
   If network-wide communication codes are present, disconnect the auxiliary heater control module. If the other codes disappear and the CAN bus stabilizes, the module is internally shorted and bringing down the network.
   Tools: Basic hand tools (Advanced)
8. [PRO TIP] Check CAN Bus Termination Resistance
   With the battery disconnected, measure resistance between CAN High (Pin 6) and CAN Low (Pin 14) at the OBD-II port. A healthy network reads 60 ohms. A reading of 120 ohms means a terminating resistor is offline; near 0 ohms indicates a short.
   Tools: Multimeter (Advanced)
9. [PRO TIP] Test Heater Element Resistance
   For specific applications like the Ford 6.7L DEF heater, test the heating element directly. Disconnect the heater and measure resistance between its power and ground pins. A healthy heater reads between 1.0 and 2.5 ohms. An open circuit confirms a failed heater assembly.
   Tools: Multimeter, Vehicle-specific wiring diagram (Advanced)
10. [PRO TIP] Analyze the CAN Signal with an Oscilloscope
    Connect an oscilloscope to the CAN High and CAN Low lines at the module. A good signal shows a clean, mirrored square wave. Distorted waveforms, noise, or missing packets indicate severe signal integrity problems requiring harness repair.
    Tools: Oscilloscope, Back-probe pins (Professional)

When This Code Triggers (Freeze-Frame Conditions)

• Battery Voltage: 11.5-12.5V (During key-on, before engine start)
• Ambient Air Temperature: < 40°F (5°C) (Cold start, when auxiliary heat is requested)
• Engine RPM: 0 or 600-800 RPM (Key-on engine-off or immediately after starting)
• Time Since Start: 0-30 seconds (Initial module communication check)

Related Codes

• U0165 — Lost Communication With Auxiliary Heater Control Module. U0425 means the module is talking but sending corrupt data; U0165 means the module is completely dead or disconnected. Diagnose U0165 first by checking power and ground.
• U0424 — Invalid Data From HVAC Control Module. Often appears alongside U0425 because the systems are linked. Diagnose the main HVAC module (U0424) first, as it acts as the primary controller.
• U0422 — Invalid Data From the Body Control Module (BCM). The BCM acts as a network gateway. A fault here triggers U0425 as a secondary symptom. Fix the BCM issue to resolve the U0425 code.
• U3000 — Control Module Internal Failure. If the auxiliary heater module logs U3000, it has self-diagnosed a fatal internal hardware fault and requires immediate replacement.

Climate & Environmental Factors

• Cold Climates: In diesel vehicles, the auxiliary heater prevents Diesel Exhaust Fluid (DEF) from freezing at 12°F (-11°C). A U0425 failure in winter forces the truck into a speed-limited 'limp mode' or a no-start condition.
• High Humidity / Water Exposure: Moisture accelerates corrosion on wiring connectors and internal circuit boards. Vehicles with known water leak issues (clogged sunroof drains, bad cowl seals) are highly susceptible to the electrical shorts that cause U0425.
• Road Salt: Road salt creates a highly corrosive environment for undercarriage wiring. This severely damages DEF heater harnesses and module connectors, leading to immediate communication errors.

How to Talk to a Mechanic About This Code

Say this: "I have a U0425 code and need a diagnostic appointment. I authorize one hour of diagnostic time. Please check for TSBs, verify power and ground at the auxiliary heater module, and check the CAN bus for other communication errors before quoting a module replacement."

This signals you understand U0425 is a network code requiring a proper diagnostic process. It prevents a shop from immediately quoting a $1,000 module replacement without ruling out a $50 wiring repair or a $150 software update.

Avoid saying:

• 'My heater isn't working right, can you fix it?' (Too vague, invites expensive guesses)
• 'Just replace the auxiliary heater module.' (You are authorizing an expensive part you may not need)
• 'My check engine light is on, what's wrong with it?' (Invites a minimal scan and a potential upsell)

Questions to ask before authorizing the repair:

• What were the exact voltage and ground readings at the module connector?
• Are there any Technical Service Bulletins (TSBs) for this code on my vehicle?
• Does the replacement module require VIN programming, and is that included in the quote?
• What is the warranty on the repair, covering both parts and labor?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Recommended if a software update (TSB) is the likely fix or if the vehicle is under warranty. For out-of-warranty vehicles, an independent shop is more cost-effective.
  Best for: Vehicles under warranty or covered by a specific TSB (e.g., Ford's DEF heater program)., Complex software reflashing or module programming requiring proprietary manufacturer tools., Known manufacturer-specific issues where the dealer has direct access to engineering data.
  Downsides: Highest labor rates and parts costs., Defaults to replacing entire assemblies rather than repairing specific wires or connectors. (Typical cost: +40% vs. baseline)
• Independent Shop: Best fit for most out-of-warranty scenarios. A shop with strong electrical diagnostic skills effectively traces wiring and network faults at a lower cost than the dealer.
  Best for: Out-of-warranty vehicles where cost is a major factor., Diagnosing network and electrical issues, provided the shop has an oscilloscope and bidirectional scanners., Building a long-term relationship with a trusted mechanic.
  Downsides: Diagnostic capabilities vary widely; ensure they have advanced tools., Lacks access to the latest manufacturer software for brand-new models. (Typical cost: +0% vs. baseline)
• Chain Shop: Not recommended. U0425 is a complex communication code requiring a diagnostic skill set and programming tools not found at chain shops.
  Best for: Simple, routine maintenance like oil changes, tires, and brake pads.
  Downsides: Technicians lack specialized training for complex CAN bus network diagnostics., High pressure to meet sales targets leads to misdiagnosis and unnecessary parts replacement., Not equipped for module programming or advanced software troubleshooting. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost exceeds 40-50% of the car's private-party value, seriously consider selling or trading it in rather than repairing it.

• Car worth $5000, fix is $2200: Walk away. The repair cost is nearly half the car's value, and other age-related issues are imminent.
• Car worth $15000, fix is $1100: Fix it. The repair cost is well below the threshold and is necessary for vehicle function in cold climates.
• Car worth $3000, fix is $1200: Borderline. Get a second opinion. If the fix is guaranteed, it might be worth it, but prepare for other repairs soon.

What Scan Tool You Need for This Code

Minimum: A full-system scanner that reads manufacturer-specific codes and views live data. A basic $20 code reader is useless for a 'U' code diagnosis.

A cheap reader only confirms U0425 exists. It cannot see if other modules are offline, view the data the module is sending, or check software versions. Diagnosing a network code requires seeing how all modules communicate.

Budget: BlueDriver Pro (~$100) — Reads manufacturer-specific 'U' codes from all modules, views live data from the auxiliary heater module, and checks for TSBs within its app.

Mid-range: Innova 5610 / Foxwell NT809 (~$350) — Provides full bidirectional control to command the auxiliary heater on and off to test its function directly. Graphs live data to isolate module vs. wiring faults.

Professional: Autel MaxiCOM MK808S (~$400) — Offers OEM-level diagnostics, bidirectional control, module resets, and a detailed view of the entire network topology to definitively diagnose communication faults.

Rent vs buy: Rent a scanner from a parts store to confirm the code, but it lacks the power for a full diagnosis. For U0425, buy a bidirectional tool or pay the $150 diagnostic fee at a professional shop.

How to Clear the Code After You Fix It

1. Reconnect battery if disconnected for repair.
2. Use a compatible OBD-II scan tool to erase the Diagnostic Trouble Codes (DTCs).
3. Perform a complete drive cycle to allow readiness monitors to run.

Drive cycle (~30 minutes): Start with a cold soak (engine off for 8+ hours). Start engine and idle for 2-3 minutes with A/C and rear defroster on. Accelerate to 55 mph and hold steady for 3-5 minutes. Decelerate without braking. Perform 15-20 minutes of stop-and-go city driving.

Readiness monitors affected: Comprehensive Component Monitor, CAN Bus System Monitor

Before emissions retest: drive at least 100 miles to fully set monitors.

Watch out for:

• Disconnecting the battery clears the code but resets all readiness monitors, causing an automatic emissions test failure.
• The code returns immediately upon startup if the root cause (bad wiring, faulty module) remains unaddressed.

Will This Fail Emissions / State Inspection?

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

• California: An illuminated Check Engine Light is an automatic failure. After repair, the vehicle must complete a drive cycle to set readiness monitors before re-testing.
• New York: Automatic failure if the Check Engine Light is on. For 2001+ vehicles, only one readiness monitor is allowed to be 'Not Ready'. Clearing the code resets all monitors.
• Texas: In emissions-testing counties, an illuminated Check Engine Light results in automatic failure. The code must be repaired, cleared, and monitors set to pass.

Most Commonly Affected Vehicles

• Ford F-Series Super Duty (Diesel) (2011-2016) — On 6.7L Power Stroke engines, this code flags a failed Diesel Exhaust Fluid (DEF) reservoir heater. The heater assembly (Part # BC3Z-5J225-L) is a notorious failure point.
• Land Rover Discovery / Range Rover Sport (2005-2016) — Frequently logs U0425 due to failures in their complex fuel-fired auxiliary heaters (Webasto units). Software updates frequently resolve spurious communication faults.
• Dodge / Ram 2500 / 3500 (2013-2018) — Experiences high failure rates with HVAC control modules, leading to communication codes. Replacement modules strictly require dealer VIN programming.
• Ford Escape (2013-2019) — The HVAC control module fails to enter sleep mode, causing severe parasitic battery drains that trigger U0425. TSBs exist for software updates.
• Chevrolet / GMC Silverado / Sierra (2007-2014) — Climate control module failures (e.g., Dorman 599-003 replacements) disrupt the network. Isolate the module to confirm it is the source of the data corruption.
• Volkswagen / Audi TDI Models (Jetta, Golf, Passat) (2009-2015) — TDI models use an auxiliary electric (PTC) heater for instant cabin heat. Failures of the integrated control module trigger U0425 and disable supplemental heat.

Manufacturer-Specific Notes

• Ford: Ford issued Customer Satisfaction Program 18M01 for 2011-2015 Super Duty trucks, extending the warranty on the DEF reductant heater to 11 years or 120,000 miles. TSB 23-2161 also addresses wiring connector water intrusion on 2016-2022 diesels.
• GM (Chevrolet/GMC): A failing airbag module or faulty factory radio disrupts the entire GM LAN communication network, causing the heater control to appear faulty and set U0425. Isolating modules one by one is mandatory.
• Dodge / Ram: Replacement HVAC and auxiliary heater modules require a 'Restore Vehicle Configuration' procedure using the wiTECH diagnostic tool. Plug-and-play installation is impossible.
• Land Rover: Uses a complex Webasto fuel-operated heater. Failures stem from the heater's dedicated fuel pump or glow plug, not just the control module. A specialized Land Rover scanner is required to prime and test the fuel lines.

Real Owner Stories

2015 GMC Sierra 2500HD at 115K miles

Check engine light and 'Service Emission System' message appeared during a cold snap. Truck entered limp mode with a 65mph speed limit.

What they tried:

1. Cleared the code with a basic scanner, but the message and limp mode returned immediately.

Outcome: A shop diagnosed a failed DEF tank heater. The owner replaced the DEF heater assembly (Dorman 904-613) themselves. After replacement, the codes cleared, and the truck returned to normal operation. Total cost was $250 for the part.

Lesson: On modern diesel trucks, emission system faults trigger hard speed limitations. Clearing the code is useless; the underlying hardware must be repaired to restore function.

2012 Land Rover LR4 at 88K miles

U0425 code present with no heat from the auxiliary fuel-fired heater. The main heater worked but warmed the cabin slowly.

What they tried:

1. A mechanic suspected the main HVAC module, but diagnostics showed it communicating correctly.
2. Further investigation isolated the separate fuel-burning heater module.

Outcome: The fuel-burning heater's control module was faulty. The entire Webasto heater assembly was replaced for $1,100, restoring auxiliary heat and clearing the code.

Lesson: In vehicles with complex, separate heating systems, the 'auxiliary heater' is a distinct unit. Diagnosis must focus on that specific component, not the main climate control panel.

2013 Ford Escape at 130K miles

Intermittent U0425 code, but the primary symptom was a dead battery every three days. Heating functioned normally.

What they tried:

1. Replaced the battery, but the drain continued.
2. Performed a parasitic draw test and found a 500mA current draw when the car was off.
3. Pulled fuses to isolate the draw to the HVAC control module circuit.

Outcome: The HVAC control module failed to enter sleep mode, causing the drain and sending corrupt data. Replacing and programming the module ($450 total) resolved both issues.

Lesson: A parasitic battery drain is a major red flag for this code. A systematic parasitic draw test is the correct diagnostic path before replacing parts randomly.

How to Prevent This Code From Triggering

• Inspect and clean module connectors (Every 2 years) — Moisture and road salt cause corrosion on connector pins, increasing resistance and corrupting data signals. Cleaning and applying dielectric grease seals out moisture.
• Test battery health and clean terminals (Annually (before winter)) — Control modules are highly sensitive to voltage drops. A weak battery causes modules to reset or send garbled data during startup, triggering U0425.
• Clear cowl and sunroof drains of debris (Every 6 months) — Clogged drains force rainwater to overflow directly onto sensitive electronic modules and connectors, causing immediate water damage and failure.
• Apply software updates when available (During routine dealer service) — Manufacturers release firmware updates to fix software bugs causing communication glitches. An update resolves persistent U0425 codes without replacing parts.

Frequently Asked Questions

What is an auxiliary heater?

An auxiliary heater is a secondary system designed to warm the cabin or engine coolant faster than the main heater. It uses an electric element in EVs and modern cars, or a small fuel-burning furnace in diesel and European vehicles.

Can I fix a U0425 code myself?

You can perform basic checks like inspecting fuses, testing the battery, and visually checking wiring for damage. However, fixing the root cause requires a professional scanner to program the new module. Stop DIY and go to a shop if basic power and ground checks pass.

Will the code go away on its own?

If the fault was a temporary voltage drop, the code moves to 'stored' status after several drive cycles and clears itself. If caused by a failing part or persistent wiring issue, the code remains active until repaired.

How much does it cost to diagnose a U0425 code?

A diagnostic check at a repair shop costs between $120 and $180. This covers the technician's time to trace the network fault using specialized scan tools and oscilloscopes.

What are the most common misdiagnoses for U0425?

A common mistake is replacing the module without testing the battery or checking for software updates. Another pitfall is ignoring other 'U' codes, as U0425 is often a symptom of a larger network problem.

Can a bad battery cause a U0425 code?

Yes. Control modules are highly sensitive to voltage drops. A weak battery causes voltage to plummet during startup, triggering communication glitches and the U0425 code.

What is the difference between code U0425 and P0425?

They are completely different codes. U0425 is a network communication error from the auxiliary heater module. P0425 is a powertrain code indicating a Catalyst Temperature Sensor Circuit Malfunction.

Key Takeaways

• Code U0425 flags corrupted data from the auxiliary heater module, immediately disabling supplemental cabin heat or the diesel DEF heater.
• Test your battery first; voltage drops below 10V during startup trigger 30% of false communication codes like U0425.
• You can drive with this code, but a malfunctioning module failing to enter sleep mode drains a healthy battery overnight.
• Check for Technical Service Bulletins (TSBs) before buying parts; manufacturers frequently resolve U0425 with a 1-hour software reflash costing $150-$300.
• Replacing the module costs $400 to $1,150 and requires a professional J2534 Pass-Thru device to program the new unit to your vehicle's VIN.