What Does C1265 Mean?
The ABS module has detected a short to ground in the warning lamp relay circuit. The relay that controls the ABS/brake warning indicator lamp has its control circuit pulled to ground, which may cause the warning lamp to malfunction — either staying on permanently or not illuminating when it should. This affects the driver's ability to be warned about brake system faults.
Common Causes
35%
Chafed or damaged wiring in the warning lamp relay control circuit shorting to ground
25%
Failed warning lamp relay with internal short
20%
Corroded ABS module connector with pin-to-ground bridging
10%
ABS module internal relay driver circuit failure
10%
Instrument cluster internal fault pulling the relay circuit to ground
Diagnostic Steps
1
Locate the ABS warning lamp relay (check under-hood fuse box or ABS module area). Remove the relay and measure resistance from the control coil pin to ground — should be open (infinite). Any measurable resistance indicates a short in the downstream wiring.
2
With the relay removed, check the ABS module connector relay driver output pin for continuity to ground — should be open. If shorted, the module driver has failed internally.
3
Inspect the wiring harness from the ABS module to the relay socket for chafing, especially where it routes through firewalls, along frame rails, or near metal edges.
4
Check the ABS module connector for water damage, corrosion, or debris that could create a conductive path from the relay driver pin to an adjacent ground pin.
5
If wiring tests clean with the module disconnected but the short appears when connected, the ABS module has an internal driver failure and needs replacement.
Estimated Repair Cost
$50 - $600
Parts + labor, varies by vehicle and location
The ABS module has detected a short to ground in the warning lamp relay circuit. The relay that controls the ABS/brake warning indicator lamp has its control circuit pulled to ground, which may cause the warning lamp to malfunction — either staying on permanently or not illuminating when it should. ...
The most common cause of C1265 (Lamp Warning Relay Circuit Short To Ground) is: Chafed or damaged wiring in the warning lamp relay control circuit shorting to ground
Typical repair costs for C1265 range from $50 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the warning lamp relay is shorted, the brake warning system may not properly alert the driver to genuine brake faults like low fluid or hydraulic pressure loss. Manually verify brake fluid level and brake system condition. Safe to drive short distances, but the warning system is compromised until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1265 to identify the root cause.
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Quick Info
Category
Chassis
System
ABS / Brake Warning System
Difficulty
Type
Manufacturer
Recommended Tools
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