Diagnostic Test
- CHECK IF THE DTC IS ACTIVE NOTE:
Make sure the Stop Lamp Switch is properly adjusted before continuing.
- Turn the ignition on.
- Press and release the Brake Pedal.
- With the scan tool, read Electric Vehicle Control Unit (EVCU) DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to STANDARD PROCEDURE .
- CHECK THE (B135) BRAKE SIGNAL 1 CIRCUIT FOR A SHORT TO GROUND
- Turn the ignition off. Remove the key from the Ignition Switch, close doors and allow the EVCU to shut down.NOTE:
Allow up to two minutes for the EVCU to shut down. Opening the vehicle door will interrupt the shut down process.
- Disconnect the Stop Lamp Switch harness connector.
- Disconnect the EVCU C1 harness connector.
- Measure the resistance between ground and the (B135) Brake Signal 1 circuit at the Stop Lamp Switch harness connector.
Is the resistance below 100k Ohms?
Yes
- Repair the (B135) Brake Signal 1 circuit for a short to ground.
- Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Go To 3
- Turn the ignition off. Remove the key from the Ignition Switch, close doors and allow the EVCU to shut down.
- CHECK THE (B135) BRAKE SIGNAL 1 CIRCUIT FOR AN OPEN
- Measure the resistance of the (B135) Brake Signal 1 circuit between the Stop Lamp Switch harness connector and the EVCU C1 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the (B135) Brake Signal 1 circuit for an open.
- Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- Measure the resistance of the (B135) Brake Signal 1 circuit between the Stop Lamp Switch harness connector and the EVCU C1 harness connector.
- CHECK THE FUSED B(+) CIRCUIT FOR AN OPEN
- Using a 12-volt test light connected to ground, check the Fused B(+) circuit at the at the Stop Lamp Switch harness connector.NOTE:
The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
Does the test light illuminate brightly?
Yes
- Go To 5
No
- Repair the Fused B(+) circuit for an open.
- Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
- Using a 12-volt test light connected to ground, check the Fused B(+) circuit at the at the Stop Lamp Switch harness connector.
- STOP LAMP SWITCH
- Reconnect the EVCU C1 harness connector.
- Connect a jumper wire between the (B135) Brake Signal 1 circuit and the Fused B(+) circuit in the Stop Lamp Switch harness connector.
- Turn the ignition on.
- With the scan tool, read the Brake Switch Normally Open State.
Does the Brake Switch Normally Open State read Closed?
Yes
- Replace the Stop Lamp Switch in accordance with the Service Information. Refer to SWITCH, STOP LAMP, REMOVAL .
- Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Go To 6
- ELECTRIC VEHICLE CONTROL UNIT (EVCU)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Brake Lamp Switch and the Electric Vehicle Control Unit (EVCU).
- Look for any chafed, pierced, pinched or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals.
- Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .
No
- Replace and program the Electric Vehicle Control Module (EVCU) in accordance with the Service Information. Refer to UNIT, ELECTRIC VEHICLE CONTROL (EVCU), REMOVAL .
- Perform the EVCU VERIFICATION TEST. Refer to STANDARD PROCEDURE .