What Does B2557 Mean?
This code indicates that the Body Control Module (BCM) has detected a short to battery voltage in the control circuit for the left power sliding door motor or actuator. The BCM expected to see a lower voltage when commanding the door open or closed, but instead detected continuous battery voltage, suggesting current is flowing when it shouldn't be. This electrical fault prevents proper control of the left sliding door's automatic operation.
Common Causes
45%
Damaged or chafed wiring harness in door jamb area causing short to B+ wire
30%
Failed power sliding door motor module with internal short circuit
15%
Corroded or damaged connector terminals at door motor creating cross-circuit short
10%
Failed Body Control Module with shorted output driver circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of the left sliding door wiring harness in the door jamb area where it flexes during operation. Look for chafed, pinched, or damaged insulation exposing copper wire that could contact battery voltage wires.
2
Step 2: Disconnect the left power sliding door motor connector and measure voltage on the control circuit wire at the harness side using a digital multimeter. With door commands inactive, voltage should be 0V; if battery voltage is present, the short is in the harness between BCM and motor.
3
Step 3: If no voltage present at disconnected harness, measure resistance from the motor-side connector control circuit pins to ground and to battery positive. Resistance to B+ should be >10k ohms; lower readings indicate internal motor module short circuit.
4
Step 4: Inspect all connector terminals for corrosion, bent pins, or moisture intrusion that could cause cross-circuit shorts. Clean or replace connectors as needed using electrical contact cleaner and dielectric grease.
5
Step 5: If wiring and motor test good, suspect BCM internal fault. Monitor control circuit voltage with BCM connected while commanding door operation. Voltage that doesn't switch properly indicates failed BCM output driver.
6
Step 6: After repairs, clear codes, cycle the power sliding door through multiple open/close operations, and verify code does not return. Perform door relearn procedure if required by manufacturer.
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected a short to battery voltage in the control circuit for the left power sliding door motor or actuator. The BCM expected to see a lower voltage when commanding the door open or closed, but instead detected continuous battery voltage, s...
The most common cause of B2557 (Left Power Sliding Door Open/Close Output Circuit Short to Battery) is: Damaged or chafed wiring harness in door jamb area causing short to B+ wire
Typical repair costs for B2557 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive, but the left power sliding door will not operate automatically and may need to be manually opened/closed. Door could potentially fail to latch properly or open unexpectedly if electrical fault affects other door functions, so verify manual operation and latching before driving.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2557 to identify the root cause.
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Quick Info
Category
Body
System
Power Sliding Door System
Difficulty
Type
Generic (SAE)
Recommended Tools
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