Diagnostic Test

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. Turn the ignition on.
2. With the scan tool, record and erase the DTCs.
3. Start the Engine.
4. Apply brake pedal firmly with at least 80 bar (1160 psi.).
5. With the scan tool, read the DTCs.
  Does the scan tool display: C1091-ABS BRAKE LAMP CONTROL CIRCUIT HIGH?
  
  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 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. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
  No
  - Go to step 3
CHECK (B221) BRAKE LAMP ACTIVATION RELAY CONTROL SHORTED TO VOLTAGE

Fig 1: Checking Brake Lamp Activation Relay Control Shorted To Voltage
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module
3. Disconnect the Brake Lamp Activation Relay.
4. Turn the ignition on.
5. 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 Activation Relay Control circuit.
  - Perform the ABS VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .
  No
  - Go to step 4
BRAKE LAMP ACTIVATION RELAY

Fig 2: Checking Brake Lamp Activation Relay
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Measure the resistance across the relay between the (B221) Brake Lamp Activation Relay Control Circuit and the (F943) Fused Ignition switch Output.
  Is the resistance 75 - 95 Ohms?
  
  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
  - Replace the Brake Lamp Activation Relay in accordance with the Service Information.
  - Perform the ABS VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Antilock Brake (ABS) - Standard Procedure .