OBD-II Code B1738: Driver Memory Position Error

What Does B1738 Mean?

OBD-II code B1738 is a Body code indicating an open electrical circuit in the driver's memory position system. The vehicle's computer lost communication with the controls for the power seat, side mirrors, or adjustable pedals, preventing the system from recalling your saved settings.

Technical definition: The standard SAE definition is "Mirror Driver Horizontal Switch Circuit Open". However, General Motors and Ford use B1738 to flag a general open circuit within the Driver Seat Memory Module. On Hyundai and Kia vehicles, B1738 means "P-SIS front – Driver Wrong ID," indicating a critical failure in the Pressure-Side Impact Sensor for the airbag system.

Can I Drive With B1738?

✅Yes. This code does not affect engine operation or safety systems in most vehicles. You can drive the car, but memory seat, mirror, or steering column features will not work. Warning: On Hyundai and Kia models, B1738 flags a disabled side airbag system; do not drive if the airbag light is illuminated.

Common Causes

• Damaged or Pinched Wiring Under Driver's Seat (Very Common) — The wiring harness under the power driver's seat moves every time the seat is adjusted. Over time, these wires stretch, pinch, or cut, causing an open circuit.
• Corroded or Loose Electrical Connector (Common) — The main electrical connector under the seat or memory switch loosens or corrodes from moisture, severing communication. Unplugging and reconnecting this plug often resolves the issue temporarily.
• Faulty Driver Memory Switch (Common) — The door or seat-mounted switch panel fails internally. Spilled liquids are the primary cause of switch failure.
• Incorrect System Re-learn Procedure (Common) — After a battery replacement, many vehicles require a specific procedure to 're-learn' seat positions. Failing to perform this calibration triggers a fault code because the module loses its travel limits.
• Blown Fuse or Faulty Circuit Breaker (Less Common) — A blown fuse or tripped circuit breaker instantly cuts power to the memory seat module, disabling the entire system.
• Poor Ground Connection (Less Common) — A corroded or loose ground wire for the memory seat module severs the circuit, causing intermittent or complete system failure.
• Low Key Fob Battery (Rare) — Modern memory positions link to specific key fobs. A dead fob battery prevents the car from identifying the driver, blocking memory recall.
• Failed Driver Seat Memory Module (Rare) — The memory control module fails due to internal hardware degradation or software glitches requiring dealer reprogramming.

Symptoms

• Memory seat, mirrors, or pedals do not adjust — Pressing the memory '1', '2', or 'Set' buttons yields no response from the seat, mirrors, or adjustable pedals.
• Airbag warning light is on (Hyundai/Kia) — On Hyundai and Kia models, the airbag warning light illuminates, indicating a disabled side impact sensor.
• Power seat adjustment is erratic or reversed — The power seat works intermittently or controls reverse (e.g., pressing forward moves the seat backward), a known software glitch on GM vehicles.
• Memory switch light is off — The indicator light on the memory buttons remains dark, confirming the system lacks power or communication.
• Check Engine Light (MIL) Illuminated — In rare cases, a body code like B1738 triggers the main Check Engine Light on the dashboard.

Diagnostic Flowchart

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

Common Fixes & Costs

• Replace Blown Fuse — Parts: $1-$5, Labor: $0, ~0.1 hr book time (DIY)
• Repair Damaged Wiring Under Seat — Parts: $5-$20, Labor: $150-$300, ~1.5 hr book time (Intermediate)
• Replace Driver Memory Switch — Parts: $25-$250, Labor: $100-$350, ~0.8 hr book time (DIY)
• Clean or Repair Ground Connection — Parts: $1-$10, Labor: $50-$150, ~0.5 hr book time (DIY)
• Reprogram Driver Seat Module — Parts: $0, Labor: $100-$200, ~1.0 hr book time (Professional)
• Replace Driver Seat Memory Module — Parts: $150-$600, Labor: $250-$800, ~1.2 hr book time (Professional)

DIY vs Professional

• Replace Blown Fuse 🟢 Beginner
  Tools: Fuse puller
• Repair Damaged Wiring Under Seat 🟢 Beginner
  Tools: Soldering iron, heat shrink tubing, wire strippers, multimeter
• Replace Driver Memory Switch 🟢 Beginner
  Tools: Trim removal tools, screwdriver set
• Clean or Repair Ground Connection 🟢 Beginner
  Tools: Socket set, wire brush, sandpaper
• Replace Driver Seat Memory Module 🟢 Beginner
  Tools: Socket set, trim removal tools, dealer-level scan tool

Used vs. New Parts: Buying Guide

When a used part is worth it: For a simple memory switch, a used part from a reputable auto recycler is cost-effective. For control modules, a used part carries a high risk of being locked to the donor vehicle's VIN.

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

Donor quality checklist:

• Ensure switch button graphics are not worn off.
• Match module part numbers exactly.
• Verify the donor vehicle was not involved in a flood.

Decision logic:

• If The part is a simple switch and the new OEM part costs over $150 → A used switch is a reasonable gamble to save money.
• If The part is a control module that requires dealer programming → Buy new or use a specialized remanufacturing service.
• If The vehicle is a Hyundai/Kia and the part is the airbag sensor → Always buy new. Never risk safety with used SRS components.

Warranty tradeoff: Used parts typically have a 30-90 day warranty. New aftermarket parts carry a 1-year to limited lifetime warranty.

Worst-case if a used part fails: $400 if a used module fails, requiring a second labor charge and a new part.

What Happens If You Wait — Timeline

1. Immediate: Code B1738 is stored. Memory seat, mirror, and pedal functions stop working. Manual power seat controls usually still function. (MPG impact: 0%% · Added cost: $0)
2. Immediate (Hyundai/Kia Airbag Fault): Code B1738 is stored and the airbag warning light is on. The driver's side impact sensor is disabled. (MPG impact: 0%% · Added cost: Potentially infinite in the event of an accident.)
3. 1-6+ months: The broken wire shorts to ground or power, blowing the system's fuse. (MPG impact: 0%% · Added cost: $5 to $150)
4. 6-12+ months: The short circuit sends incorrect voltage back to the Driver Seat Module, destroying its internal circuits. (MPG impact: 0%% · Added cost: $400 - $1000+)

Cost of Not Fixing It

• Immediate: Loss of memory seat, mirror, and pedal functionality. (Added cost: Negligible)
• Immediate (Hyundai/Kia specific): The driver's side airbag system is disabled and will not deploy in a collision. (Added cost: Potentially infinite in case of an accident.)
• 1-6+ months: An ignored open circuit in a wiring harness shorts to another wire, blowing fuses or destroying the control module. (Added cost: $100 - $800+)

Diagnosis Steps

1. Check the Fuse
   Locate the memory seat or driver's door module fuse in the interior fuse box. Replace it if the internal metal filament is broken.
   Tools: Fuse puller or needle-nose pliers (Beginner)
2. Inspect and Reset Under-Seat Wiring
   Slide the seat fully forward and up. Inspect the wiring harness for cut wires or pinched insulation. Disconnect the main electrical plug, wait 60 seconds, and reconnect it to hard-reset the module.
   Tools: Flashlight (Beginner)
3. Scan Codes and Perform Wiggle Test
   Connect an advanced OBD-II scanner capable of reading Body (B) codes. While viewing live data for the seat position sensor, gently wiggle the under-seat harness; erratic data confirms a broken wire.
   Tools: Advanced OBD-II Scanner (with live data) (Intermediate)
4. Test the Memory Switch
   Remove the door panel trim to access the switch connector. Use a multimeter set to continuity; a reading of 'OL' (Open Loop) when pressing a button confirms a dead switch.
   Tools: Multimeter, trim removal tools (Advanced)
5. Check Module Power and Ground
   Locate the Seat Memory Module. Use a multimeter to verify 12.0V+ at the power pin and less than 100mV voltage drop on the ground pin while activating a seat function. High voltage drop indicates a failing ground connection.
   Tools: Multimeter, wiring diagram (Advanced)

When This Code Triggers (Freeze-Frame Conditions)

• System Voltage: 11.5V - 14.5V (The fault sets during a key-on self-test or when a memory function is commanded.)
• User Action: Memory Button Press (The code sets the instant a user presses a memory button and the module detects an open circuit.)

Related Codes

• B1737 — Indicates a general circuit failure. B1738 specifically flags an 'open' circuit (infinite resistance), while B1737 suggests erratic voltage from a loose connection.
• B1739 — Indicates a 'short to battery'. A multimeter on the signal wire shows constant 12V power, whereas B1738 shows 0V.
• B1740 — Indicates a 'short to ground'. A multimeter shows near 0 ohms resistance to the chassis, whereas B1738 shows infinite resistance (OL).
• U0073 — Control Module Communication Bus Off. If paired with B1738, the seat module has failed completely and is crashing the vehicle's CAN bus network.

Climate & Environmental Factors

• Moisture and Road Salt: High humidity and tracked-in snow melt accelerate corrosion on under-seat connectors and door-mounted switches, causing open circuits.
• Cold Weather: Freezing temperatures make plastic wire insulation brittle, increasing the likelihood of wires snapping as the seat moves.

How to Talk to a Mechanic About This Code

Say this: "I have an OBD-II code B1738. I understand this is a Body code for a 'Driver Memory Position Error'. I suspect it's a wiring issue under the driver's seat, so please start by checking the harness for continuity before quoting a new module. (For Hyundai/Kia owners: 'I have a B1738 code and my airbag light is on. I need a diagnostic for the SRS system to check the driver's side impact sensor.')"

This directs the technician to the most likely and cheapest cause (wiring) first, preventing them from immediately quoting an expensive module replacement.

Avoid saying:

• 'My memory seat isn't working.'
• 'Just fix whatever is wrong with the seat.'
• 'I read online it's the module, can you replace it?'

Questions to ask before authorizing the repair:

• Did you find the specific open circuit in the wiring harness or the switch?
• Can you confirm the seat module is receiving power and has a good ground?
• If you are recommending a module replacement, what tests did you do to rule out the wiring and switch?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Necessary for the Hyundai/Kia airbag variant; otherwise, only use if the issue is a known software bug.
  Best for: Hyundai/Kia vehicles where B1738 indicates a critical airbag system fault., GM vehicles that need a module reprogrammed per a TSB.
  Downsides: Highest labor rates., May prefer to replace an entire wiring harness rather than repair a single broken wire. (Typical cost: +50% vs. baseline)
• Independent Shop: Best fit. An experienced independent technician is the most cost-effective choice for diagnosing wiring-related causes.
  Best for: Out-of-warranty vehicles with the standard memory seat fault., Electrical diagnostics and wiring repairs.
  Downsides: May not have the tools to reprogram modules if that is the ultimate issue. (Typical cost: +0% vs. baseline)
• Chain Shop: AVOID. This code requires diagnostic skill, not just part swapping.
  Best for: Simple part replacement like a fuse.
  Downsides: Technicians often lack specialized skills for complex electrical diagnosis., High risk of misdiagnosis. (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, pause and consider your options.

• Car worth $5000, fix is $350: Fix it. This is a minor cost to restore a convenience feature.
• Car worth $4000, fix is $1200: Borderline. The memory seat isn't critical. Consider living with the problem.
• Car worth $6000, fix is $3100: Walk away (for Hyundai/Kia airbag issue). The repair cost is over 50% of the car's value, and the vehicle is unsafe to drive.

What Scan Tool You Need for This Code

Minimum: A scanner that can read Body (B) and SRS (B) codes. Basic sub-$50 readers that only handle Powertrain (P) codes will not see B1738.

A cheap, engine-only code reader will show 'No Codes Found'. To diagnose B1738, you must have a tool that communicates with the Body Control Module.

Budget: BlueDriver Pro, Foxwell NT301 (~$99) — Confirms the B1738 code is present and allows you to clear it. Offers live data via a smartphone app to perform a 'wiggle test'.

Mid-range: Foxwell NT510 Elite, XTOOL Anyscan A30M (~$180) — Provides manufacturer-specific definitions and live data PIDs to see if the module registers button presses in real-time.

Professional: Autel MaxiCOM MK808S (~$450) — Offers full bidirectional control to command the seat module to perform actions like 'run seat calibration'.

Rent vs buy: Most free loaner tools from auto parts stores only read basic engine codes and will NOT see a B1738 Body code. You will likely need to buy a capable scanner.

How to Clear the Code After You Fix It

1. Reconnect any disconnected components with the ignition off.
2. Use an OBD-II scan tool capable of reading Body (B) codes to clear the fault code.
3. Perform the memory seat initialization/re-learn procedure as specified in the owner's manual.

Drive cycle (~5 minutes): A formal drive cycle is not required. Turn the key to 'On', set a new memory position, and operate all power seat functions. If the code does not return, the repair is verified.

Readiness monitors affected: None. This is a body code and does not affect emissions readiness monitors.

Watch out for:

• Using a basic code reader that cannot clear Body (B) codes.
• Forgetting to perform the seat 're-learn' procedure after a battery disconnect.

Will This Fail Emissions / State Inspection?

No — by itself this code doesn't fail OBD inspection (but it can keep readiness monitors from setting, which causes a separate fail).

• New York: A B1738 code will not fail emissions. However, if the code is the Hyundai/Kia airbag variant and the airbag light is on, it fails the annual safety inspection.
• Texas: This code will not fail emissions. In counties requiring a safety inspection, an illuminated airbag light is an automatic failure.

Most Commonly Affected Vehicles

• Chevrolet Tahoe / Suburban (2007-2014) — Prone to memory module software glitches causing erratic seat movement. Fixed via dealer reprogramming (TSB #04-08-50-016C).
• GMC Yukon / Yukon XL (2007-2014) — Shares the Tahoe's module software issues and under-seat wiring harness chafing vulnerabilities.
• Ford Excursion (2000-2005) — Memory modules frequently 'lock up'. Disconnecting and reconnecting the main under-seat harness performs a hard reset and restores function.
• Ram 1500 / 2500 (2015-2020) — Failures stem from damaged under-seat wiring or dead door switches. Component replacement requires a 'Seat Calibration' via an advanced scan tool.
• Acura TL (2004-2008) — Intermittent operation traces to a failing seat control module (Part #81628-SEP-A04). Rebuilt modules are the standard fix.
• Hyundai Elantra (2004-2012) — B1738 indicates a critical 'P-SIS front – Driver Wrong ID' airbag side impact sensor failure, requiring immediate sensor replacement.
• Kia Optima / Sorento (2004-2014) — Shares Hyundai's critical airbag sensor definition. Do not ignore; the side airbag will not deploy.

Manufacturer-Specific Notes

• General Motors (Chevy/GMC): TSB #04-08-50-016C addresses seats that 'creep' or move erratically. The fix is a software update via a Tech2 scanner, not parts replacement.
• Ford: Memory modules frequently freeze. Disconnecting the large electrical plug under the driver's seat for 60 seconds forces a hard reset.
• Hyundai / Kia: B1738 is a Supplemental Restraint System (SRS) code indicating the Airbag Control Module detects a faulty or incorrect driver's side pressure impact sensor.

Real Owner Stories

2005 Chevrolet Tahoe with ~100K miles

Memory seat function worked intermittently, sometimes moving forward when it should move back.

What they tried:

1. Owner tried resetting memory positions.
2. Dealer initially found no problem.

Outcome: Dealer reprogrammed the Driver Seat Module with an updated software calibration per TSB 04-08-50-016C, fixing the issue without parts.

Lesson: For erratic seat behavior on GM trucks, research TSBs before replacing parts. A software glitch is a known cause.

2010 Hyundai Elantra at 107K miles

Airbag light illuminated with code B1738, indicating a fault with the driver's side impact sensor.

What they tried:

1. Took the car to a Hyundai dealership for diagnosis.

Outcome: The dealership quoted $3,135 for the repair, including replacing the sensor module and the entire seat track assembly.

Lesson: On a Hyundai or Kia, B1738 is a critical safety issue that can be extremely expensive. Always get a second opinion from an independent shop.

2004 Lexus IS300 after battery replacement

After replacing the battery, the memory seat buttons stopped working entirely.

What they tried:

1. Owner initially thought the switch had failed.

Outcome: The owner found the correct 're-learn' procedure online, restoring full function without any cost or parts.

Lesson: If memory functions stop working immediately after a battery disconnect, always perform the memory seat initialization procedure before diagnosing a fault.

How to Prevent This Code From Triggering

• Keep the area under the front seats clear (Always) — Prevents items like water bottles from rolling under the seat, snagging, and damaging the delicate wiring harness during seat adjustment.
• Apply dielectric grease to the main connector housing (During any related repair) — Blocks moisture and humidity from entering and causing corrosion on the electrical pins.
• Periodically test your car battery (Annually) — A weak battery causes low voltage conditions during startup, corrupting the memory and calibration of electronic modules.

Frequently Asked Questions

Can I still adjust my seat manually with code B1738?

Yes, standard power seat adjustment controls usually still work. The fault isolates to the memory recall function. Exception: On Hyundai/Kia, this is an airbag code and does not affect the seat.

Will clearing the code fix the problem?

No. Clearing the code only erases it temporarily. The code returns immediately once the computer runs its self-test and detects the open circuit.

Why did my memory seat start working backwards?

This happens when the control module's software corrupts due to an out-of-range sensor signal. It is highly common on GM vehicles. A dealer software update resolves it.

I replaced the memory switch but the code came back. What did I misdiagnose?

Replacing the switch without testing the wiring harness is the most common error. Wires under the seat break constantly from movement. Always verify wire continuity before buying parts.

The memory function stopped working after I replaced the car battery. What happened?

Vehicles require a 're-learning' procedure after power loss so the module learns the seat's physical limits. Check your manual for the sequence, which usually involves moving the seat to its extreme limits.

Is it expensive to fix code B1738?

Costs range from $5 for a fuse to $800+ for a new control module. A typical shop diagnostic fee runs $120-$170 to pinpoint the exact electrical fault. Warning: The Hyundai/Kia airbag variant often requires dealer repairs exceeding $3,000.

Can a bad battery cause a B1738 code?

Yes. A weak battery causes low voltage dips during startup, corrupting module memory settings. Test your battery and alternator if you experience multiple random electrical glitches.

What is a 'P-SIS front – Driver Wrong ID'?

It stands for 'Pressure-Side Impact Sensor Front - Driver Wrong ID' on Hyundai and Kia vehicles. The airbag module detects a faulty, incorrect, or disconnected side impact sensor. This disables the airbag and requires immediate repair.

Key Takeaways

• OBD-II code B1738 flags an open electrical circuit in the driver's memory system, disabling automatic seat, mirror, and pedal adjustments.
• Inspect the wiring harness under the driver's seat first; normal seat movement pinches or cuts these wires in over 50% of B1738 cases.
• Save $150 in diagnostic fees by checking the memory seat fuse and unplugging the main under-seat connector for 60 seconds to perform a hard reset.
• Stop driving immediately if you own a Hyundai or Kia with this code and an illuminated airbag light; B1738 indicates a disabled side-impact airbag sensor on these specific vehicles.