Diagnostic Test

ACTIVE DTC
NOTE:
Verify battery voltage is greater than 10 volts.

NOTE:
Make sure the Stop Lamp Switch is properly adjusted before continuing.
1. Start the engine.
2. Test drive the vehicle bringing the vehicle speed above 48 kph (30 mph) and back to a stop several times.
3. With the scan tool, select View DTCs.
  Is the DTC Active or Pending at this time?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
STOP LAMP SWITCH
1. Turn the ignition off.
2. Disconnect the Stop Lamp Switch harness connector.
3. Measure the resistance between the (Z908) Ground circuit terminal and the (B15) Brake Switch 1 Signal terminal in the Stop Lamp Switch.
4. Apply and release the brake pedal while monitoring the Ohmmeter.
  Does the resistance change from below 5.0 Ohms to an open circuit when pressing and releasing the brake pedal?
  
  Yes
  - Go To 3
  No
  - Verify that there is good pin to terminal contact in the Switch and Control Module connectors. Replace the Stop Lamp Switch if no problems were found in the connectors.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (B15) BRAKE SWITCH 1 SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C1 harness connector.
3. Measure the resistance between ground and the (B15) Brake Switch 1 Signal circuit at the Stop Lamp Switch harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (B15) Brake Switch 1 Signal circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .