B3381

Code

Generic B — Body

Keyless entry control module internal fault

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 12 RU: 9

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty keyless entry control module (internal electronics)
Corroded/loose power or ground connections to the module
Blown fuse supplying the module
Loss of or intermittent CAN/LIN bus communication
Software/firmware corruption in the module
Low vehicle battery or unstable supply voltage

Symptoms

Keyless/push-button entry not working or intermittent
Doors may not lock/unlock using remote or passive entry
No response from key fob; LED on fob may still work
Possible warning message or indicator related to keyless system
Unable to start vehicle with keyless start (in some vehicles)
Related modules report communication errors or fail to respond

What to check

Retrieve freeze frame and module event memory with a scan tool; note stored faults and timestamps
Check vehicle battery voltage (should be ~12.6 V resting, >11 V cranking)
Inspect fuses and fusible links for the keyless entry module circuit
Visually inspect module connectors for corrosion, bent pins, or water intrusion
Verify module power and ground with a multimeter at the module harness
Check CAN/LIN bus continuity and termination; scan for other modules reporting U-codes

Signal parameters

Module supply voltage: ~11–14.5 V (steady with ignition off/on as specified)
Module ground: low resistance to chassis ground (
CAN/LIN bus: normal bus voltage levels and presence of messages when scanned
Wake/pulse signal from fob receiver (RF activity) when fob button pressed
Current draw: no excessive parasitic current when vehicle off (module standby spec varies)
Antenna/receiver RF signal strength (diagnostic tool or scope if available)

Diagnostic algorithm

Connect a professional scan tool and read all stored U-/B- codes and module event data; clear codes and attempt to re-produce.
Verify vehicle battery condition and charge if needed; retest after full charge.
Inspect and test module power and ground at the connector: verify proper voltages with respect to ground per vehicle nominal values.
Check fuses/fusible links for the keyless entry module circuit; replace if blown and retest.
Inspect connector pins and wiring for corrosion, bent pins, damaged insulation, or water ingress; repair any faults and retest.
Verify CAN/LIN bus communication: observe messages from the keyless module and other modules; diagnose any bus faults (shorts, opens, termination).
Test key fob operation with known-good fob; verify RF receiver wakes when button pressed (use diagnostic RF test or scan-tool live data if available).
If hardware and wiring present as good, check for available software updates/recalls; perform module reprogramming/flash per factory procedure.
If reprogramming fails or internal hardware fault persists (repeated internal error stored), replace the keyless entry control module and follow required pairing/relearn procedures.
After repair or replacement, clear codes, confirm normal operation of keyless entry functions, and check for reappearance of B3381.

Likely causes

Failed module power regulator or internal component failure
Poor ground connection at module chassis ground
Intermittent CAN bus connection or termination fault
Software corruption after battery disconnect or failed update
Internal antenna/receiver failure preventing signal processing

Fault status

⚠️ Status

Internal fault detected in keyless entry control module — module reports an internal hardware/software error or failed self-test. May cause partial or total loss of remote/keyless entry functionality.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours