C1090

C1090-ABS BRAKE LAMP CONTROL CIRCUIT LOW





For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With the ignition on.

- Set Condition:
When monitoring the Brake Lamp Activation Relay Control circuit the module detects a short to ground.





1. CHECK FOR DTC C1090-ABS BRAKE LAMP CONTROL CIRCUIT LOW

NOTE: This DTC must be active for the results of this test to be valid.

1. Ignition on, engine not running.
2. With the scan tool, record and erase DTCs.
3. Start the engine.
4. Apply brake pedal firmly with at least 80 bar (1160 psi.).
5. With the scan tool, read DTCs.

Does the scan tool display: C1090-ABS BRAKE LAMP CONTROL CIRCUIT LOW?

Yes

- Go To 2

No

- Perform the ABS-INTERMITTENT CONDITION TEST. ABS Intermittent Condition Test.

2. CHECK CONNECTOR/TERMINAL FOR DAMAGE

NOTE: Check all terminals for broken, bent, pushed out, or corroded terminals.

1. Turn ignition off to the lock position.
2. Inspect the Anti-Lock Brake System (ABS) Module harness connector and the Brake Lamp Activation Relay harness connector.

Is the Anti-Lock Brake Module or any of the connectors/terminals damaged?

Yes

- Repair as necessary.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

No

- Go To 3

3. CHECK (B401) BRAKE LAMP ACTIVATION RELAY SHORTED TO GROUND




1. Turn the ignition off to the lock position.
2. Disconnect the ABS Module harness connector.
3. Ignition on, engine not running.
4. Using a 12-volt test light connected to ground, probe the (B401) Brake Lamp Activation Relay circuit at the ABS Module harness connector.

Does the test light illuminate brightly?

Yes

- Replace the Anti-Lock Brake System (ABS) Module.
- Perform ABS VERIFICATION TEST. ABS Verification Test.

No

- Go To 4

4. CHECK (A108) FUSED B(+)




1. Turn the ignition off to the lock position.
2. Disconnect the Brake Lamp Activation Relay.
3. Ignition on engine not running.
4. Using a 12-volt test light connected to ground, probe the (A108) Fused B(+) circuit at the Brake Lamp Activation Relay harness connector.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair open in the (A108) Fused B(+) circuit. Inspect the related fuse. If the fuse is open check the circuit for a short to ground.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

5. BRAKE LAMP ACTIVATION RELAY




1. Turn ignition off to the lock position.
2. Measure the resistance of the (B401) Brake Lamp Activation Relay circuit between the Brake Lamp Activation Relay and the ABS Module harness connector.

Is the resistance below 5.0 Ohms ?

Yes

- Replace the Brake Lamp Activation Relay.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

No

- Repair open in the (B401) Brake Lamp Inhibit Relay circuit.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.