B3890 - Trailer Backup Lamps Circuit

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3    What is this?
Table of contents

B3890 Possible Causes

  • Faulty Trailer Backup Lamps
  • Trailer Backup Lamps harness is open or shorted
  • Trailer Backup Lamps circuit poor electrical connection
  • Faulty Trailer Lighting Control Module

How do I fix code B3890

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

Tech Notes

B3890 02 Trailer Backup Lamps Circuit Short to Ground
B3890 04 Trailer Backup Lamps Circuit Open

Cost of diagnosing the B3890 code

Labor: 1.0

The cost of diagnosing the B3890 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

B3890 Description

The Trailer Lighting Control Module receives a serial data message from the Body Control Module (BCM) indicating that the vehicle backup lamps have been activated. The Trailer Lighting Control Module responds by applying battery voltage to the trailer backup lamp control circuit illuminating the trailer backup lamps. The Diagnostic Trouble Code (DTC) sets when the Trailer Lighting Control Module detects a short to ground or an open/high resistance in the trailer backup lamps control circuit.
OBDII Code B3890 - Trailer Backup Lamps Circuit - AutoCodes.com

B3890 More Information

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