C1091

C1091-ABS BRAKE LAMP CONTROL CIRCUIT HIGH





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

NOTE: The Electronic Stability Control (ESC) may also be referred to as Electronic Stability Program (ESP) depending on the vehicle model year and configuration. Certain components may also reference ESP, ESC, or use the traction control symbol.

- When Monitored:
With the ignition on and no system under voltage or over voltage condition present.

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





1. CHECK FOR DTC C1091-ABS BRAKE LAMP CONTROL CIRCUIT HIGH

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: C1091-ABS BRAKE LAMP CONTROL CIRCUIT HIGH?

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 System (ABS) 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 CONTROL SHORTED TO VOLTAGE




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

Does the test light illuminate brightly?

Yes

- Repair the short to voltage in the (B401) Brake Lamp Inhibit Relay Control circuit.
- Perform the ABS VERIFICATION TEST. ABS Verification Test.

No

- Go To 4

4. BRAKE LAMP ACTIVATION RELAY




1. Turn ignition off to the lock position.
2. Measure the resistance across the relay between the (B401) Brake Lamp Activation Relay Control Circuit and the (A108) Fused B(+) at the Brake Lamp Activation Relay harness connector.

Is the resistance 75 Ohms ±5 Ohms?

Yes

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

No

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