Diagnostic Test

WARNING: This page is about a different car, the 2010 Dodge Charger and 2010 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

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. Turn the ignition on.
2. With the scan tool, record and erase DTCs.
3. Start the engine.
4. Apply pressure to the brake pedal firmly with at least 80 bar (1160 psi.).
5. With the scan tool, read the DTCs.
  Does the scan tool display: C1090-ABS BRAKE LAMP CONTROL CIRCUIT LOW?
  
  Yes
  - Go to step 2
  No
  - Perform the ABS-INTERMITTENT CONDITION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
CHECK CONNECTOR/TERMINAL FOR DAMAGE
NOTE: Check all terminals for broken, bent, pushed out or corroded terminals.
1. Turn the ignition off.
2. Inspect the Anti-Lock Brake Module harness connector and the Brake Lamp 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. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
  No
  - Go to step 3
CHECK (B221) STOP LAMP RELAY OVERRIDE SIGNAL SHORTED TO GROUND

Fig 1: Checking Stop Lamp Relay Override Signal For Short To Ground
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module
3. Turn the key on.
4. Using a 12-volt test light connected to ground, probe the (B221) Stop Lamp Relay Override Signal circuit at the Anti-Lock Brake Module harness connector.
  Does the test light illuminate?
  
  Yes
  - Replace the Anti-Lock Brake Module in accordance with the service information.
  - Perform the ABS VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
  No
  - Go to step 4
CHECK (A103) FUSED B+

Fig 2: Checking Fused B+ Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Brake Lamp Relay.
3. Turn the key on.
4. Using a 12-volt test light connected to ground, probe the (A103) Fused B+ circuit at the Brake Lamp Relay harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go to step 5
  No
  - Check for open fuse, if ok repair open or short to ground in the (A103) Fused B+ circuit.
  - Perform the ABS VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
BRAKE LAMP RELAY

Fig 3: Checking Stop Lamp Relay Override Signal Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Measure the resistance of the (B221) Stop Lamp Relay Override Signal Circuit between the Brake Lamp Relay and the Anti-Lock Brake Module.
  Is the resistance below 5 Ohms?
  
  Yes
  - Replace the Brake Lamp Relay in accordance with the Service Information.
  - Perform the ABS VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
  No
  - Repair open in the (B221) Brake Lamp Inhibit Relay Control circuit.
  - Perform the ABS VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .