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B1A78ModerateBody

B1A78 on 2021-2024 Jeep Grand Wagoneer — Manufacturer-Specific Body/Security System Code

1 vehicles · 1 makes · $200-$1,800 repair

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How to diagnose and fix B1A78: most-reported vehicles

Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.

Jeep Grand Wagoneer · 2021–2024

Community reported
112 owners
Link to this issueError Codes:B1A77B1A78U0140

The second-row captain's chairs equipped with power adjustment and memory functions on Grand Wagoneer L and standard models have been reported to fail to return to memorized positions or become entirely non-operational. The seat position memory module loses stored settings after a battery event, and the seat track actuator motors can bind in the rearmost position, blocking third-row access. Owner complaints on forums and NHTSA describe seats that move to a position and stop mid-travel, or refuse to respond to the Easy Entry function.

Common Symptoms

  • Second-row seat stops mid-travel during adjustment
  • Memory seat position lost after battery disconnect or replacement
  • Easy Entry function fails to slide seat forward for third-row access
  • Seat buttons unresponsive or require multiple presses
  • Error message on cluster related to seat system

How to Fix

Reprogram seat memory module via dealer J2534 tool with latest software update. If motor binding is present, the seat track assembly requires lubrication with Mopar seat track lubricant or replacement of the seat track motor assembly. In some cases, replacing the seat control module (SCM) resolves the memory loss issue permanently.

Typical repair cost:$200 - $1,800

Research This Issue

Based on 112 owner reports

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Community Reported
Medium Confidence112 owner reportsReviewed May 2026

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Jeep · 1 issue

B1A78 code reference

General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.

Frequently asked questions

What does B1A78 mean?

B1A78 stands for "Manufacturer-Specific Body/Security System Code." B1A78 is a manufacturer-specific body code in the security-systems range with no single standardized SAE definition. As with the other B1Axx codes, it generally relates to immobilizer, key/transponder, or security-module operation, but the exact meaning varies by automaker. The specific name and causes cannot be reliably stated without brand-specific documentation. Confirm with a make-appropriate scan tool.

What are the most common causes of B1A78?

The most common causes of B1A78 are: Immobilizer or anti-theft system fault, Key/transponder recognition problem, Security module communication error, Wiring or connector fault in the security circuit, Module configuration or software issue, Faulty body control / security module. The specific cause varies by vehicle.

How much does it cost to fix B1A78?

Repair costs for B1A78 range from $200 to $1,800, depending on the vehicle and root cause.

Which vehicles are affected by B1A78?

Au7o has documented B1A78 across 1 vehicle models from 1 manufacturers: Jeep.

Related codes

  • B1A77 · Manufacturer-Specific Body/Security System Code
  • 01367 · Central Locking Pump Run Time Exceeded (Likely Leak)
  • B0081 · First Row Center Seatbelt Load Limiter Deployment Control (Subfault)
  • B0083 · Left Front Impact Sensor Circuit
  • B0092 · Left Side Restraints Sensor 2 (Subfault)
  • B0098 · Right Side Restraints Sensor 3 (Subfault)
  • B00A0 · Occupant Classification System (Subfault)
  • B0229 · Manufacturer-Specific Body Code (GM: Air Recirculation Door Position Feedback Circuit Actuator Range/Performance)
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.

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