What Does C1226 Mean?
The ABS module has detected that the brake warning lamp output circuit is shorted to ground. The module's lamp driver output is being pulled low when it should not be, or the circuit has an unintended ground path. This may cause the brake warning light to behave erratically or stay off when it should be on, which is a safety concern.
Common Causes
35%
Chafed or pinched wiring grounding the brake warning lamp output wire
25%
Corroded or water-damaged ABS module connector with pin-to-ground bridging
20%
Instrument cluster internal fault pulling the lamp circuit to ground
10%
ABS module internal driver failure on the lamp output transistor
10%
Aftermarket wiring splice creating an unintended ground path
Diagnostic Steps
1
Disconnect the ABS module connector and check the brake warning lamp output pin for continuity to ground — any reading below 10K ohms indicates a short to ground in the wiring harness.
2
Inspect the entire brake warning lamp wire route from ABS module to instrument cluster for pinched or chafed wires, especially where the harness passes through bulkheads, grommets, or along frame rails.
3
Check the ABS module connector for water damage, green corrosion on pins, or evidence of moisture intrusion that could create a ground path between pins.
4
Disconnect the instrument cluster connector and retest — if the short to ground disappears, the cluster itself has an internal fault.
5
If wiring and cluster check good, the ABS module's internal lamp driver transistor may have failed. Compare resistance readings from the lamp output pin to module ground with known specifications.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ABS module has detected that the brake warning lamp output circuit is shorted to ground. The module's lamp driver output is being pulled low when it should not be, or the circuit has an unintended ground path. This may cause the brake warning light to behave erratically or stay off when it shoul...
The most common cause of C1226 (Lamp Brake Warning Output Circuit Short To Ground) is: Chafed or pinched wiring grounding the brake warning lamp output wire
Typical repair costs for C1226 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the brake warning lamp cannot illuminate when needed, the driver will not be alerted to genuine brake system faults such as low fluid or a hydraulic imbalance. Manually verify brake fluid level and pad condition. The vehicle can be driven short distances, but the inability to see real brake warnings makes this a priority repair.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1226 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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