C1091

C1091-ABS BRAKE LAMP CONTROL CIRCUIT HIGH

For a complete wiring diagram consult Diagrams/Electrical






- When Monitored:
With the ignition on.

When Set:
When monitoring the Brake Lamp Activation Relay Control circuit the module detects a short to B+.







Diagnostic Test


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.

Turn the ignition on.
With the scan tool, record and erase DTCs.
Start Engine.
Apply brake pedal firmly with at least 80 bar (1160 psi.).
With the scan tool, read DTCs.
Does the scan tool display: C1091-ABS BRAKE LAMP CONTROL CIRCUIT HIGH?

Yes


- Go To 2


No



- Refer to the ABS-INTERMITTENT CONDITION TEST. Testing and Inspection




2. CHECK CONNECTOR/TERMINAL FOR DAMAGE

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

Turn the ignition off.
Inspect the Anti-Lock Brake 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 ABS VERIFICATION TEST. ABS Verification Test


No


- Go To 3




3. CHECK (B221) BRAKE LAMP ACTIVATION RELAY CONTROL SHORTED TO VOLTAGE




Turn the ignition off.
Disconnect the Anti-Lock Brake Module
Disconnect the Brake Lamp Activation Relay.
Turn the ignition on.
Using a 12-volt test light connected to ground, probe the (B221) 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 (B221) Brake Lamp Inhibit Relay Control circuit.
- Perform ABS VERIFICATION TEST. ABS Verification Test


No


- Go To 4




4. BRAKE LAMP ACTIVATION RELAY




Turn the ignition off.
Measure the resistance across the relay between the (B221) Brake Lamp Activation Relay Control Circuit and the (A103) Fused Ignition switch Output.
Is the resistance 75 ohms ±5 ohms?

Yes


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


No


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