Front Wiper Motor Circuit Malfunction
The B0400 code means the vehicle's onboard diagnostic system has detected: Front Wiper Motor Circuit Malfunction. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $80 - $350 (parts and labor)
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Common Symptoms
- Front wipers do not operate
- Wipers do not park in correct position
- Wiper speed does not change
- Wipers operate intermittently on their own
Probable Causes (Ranked by Likelihood)
- Faulty front wiper motor Very High
- Failed wiper relay High
- Damaged wiper wiring harness Moderate
- BCM wiper control circuit fault Low
Step-by-Step Diagnostic Procedure
-
Test wiper motor with direct 12V power
-
Check wiper fuse and relay
-
Inspect wiper motor connector and ground
-
Verify BCM wiper commands with scan tool
Frequently Asked Questions
Why do my wipers not park correctly?
The park switch inside the wiper motor tells it when to stop. A faulty switch causes random parking positions.
Can I replace just the wiper motor?
Yes, the motor is typically a separate component bolted to the wiper linkage assembly.
Are wiper motors expensive?
Front wiper motors range from $40-$120 for the part, with 1-2 hours of labor for installation.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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