Diagnostic Test

CHECK THE BRAKE SWITCH SIGNALS
1. Turn the ignition on.
2. With the scan tool, monitor both Brake Signals with the brake pedal not pressed.
3. Press and release the Brake Pedal while monitoring the state of both signals.
  NOTE:
  Either Brake Signal 1 stuck on or Brake Signal 2 stuck off can cause this DTC.
  
  Is Brake Signal 1 stuck on (PRESSED) or Brake Signal 2 stuck off (NOT PRESSED)?
  
  Yes, Brake Signal 1 is stuck on
  - Go To 2
  Yes, Brake Signal 2 is stuck off
  - Go To 6
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK THE BRAKE SWITCH FOR PROPER ADJUSTMENT
1. Visually inspect the Brake Switch for proper adjustment.
  NOTE:
  A Brake Switch that is not adjusted properly could cause Brake Switch 1 to read as PRESSED when the pedal is not being pressed.
  
  Is the switch adjusted properly?
  
  Yes
  - Go To 3
  No
  - Properly adjust the Brake Switch and retest.
CHECK THE BRAKE SWITCH FOR PROPER OPERATION
NOTE:
Brake Signal 1 is normally open inside the switch. The switch can be checked one of two ways below.
1. Disconnect the Brake Switch harness connector and measure the resistance between terminals 1 and 4 of the Brake Switch while pressing and releasing the Brake Pedal and monitor for continuity through the switch in each state (should be open when NOT PRESSED and continuity when PRESSED).
2. Back probe and measure the voltage on the Brake Switch (B135) Signal 1 circuit at the Brake Switch harness connector while pressing and releasing the Brake Pedal (should have 0 volts when NOT PRESSED and 12 volts when PRESSED).
  Is the Brake Switch functioning properly?
  
  Yes
  - Go To 5
  No
  - Go To 4
CHECK THE BRAKE SWITCH (B135) SIGNAL 1 CIRCUIT FOR A SHORT TO VOLTAGE
1. Disconnect the Brake Switch harness connector.
2. Turn the ignition on.
3. Measure the voltage on the Brake Switch (B135) Signal 1 circuit at the Brake Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the Brake Switch (B135) Signal 1 circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace the Brake Switch in accordance with the Service Information. Refer to SWITCH, STOP LAMP, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK RELATED PCM AND COMPONENT CONNECTIONS
1. Perform any Service Bulletins that apply.
2. Disconnect all PCM harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
11. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Powertrain Control Module (PCM) in accordance with the Service Information. Refer to MODULE, POWERTRAIN CONTROL (PCM), REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE BRAKE SWITCH FOR PROPER OPERATION
NOTE:
Brake Signal 2 is normally closed inside the switch. The switch can be checked one of two ways below.
1. Disconnect the Brake Switch harness connector and measure the resistance between terminals 2 and 3 of the Brake Switch while pressing and releasing the Brake Pedal and monitor for continuity through the switch in each state (should have continuity when NOT PRESSED and be open when PRESSED).
2. Reconnect the Brake Switch harness connector. Back probe and measure the voltage on the Brake Switch (B134) Signal 2 circuit at the Brake Switch harness connector while pressing and releasing the Brake Pedal (should have 12 volts when NOT PRESSED and 0 volts when PRESSED).
  Is the Brake Switch functioning properly?
  
  Yes
  - Go To 8
  No
  - Go To 7
CHECK THE BRAKE SWITCH (B134) SIGNAL 2 CIRCUIT FOR A SHORT TO VOLTAGE
1. Disconnect the Brake Switch harness connector.
2. Turn the ignition on.
3. Measure the voltage on the Brake Switch (B134) Signal 2 circuit at the Brake Switch harness connector.
  Is there any voltage present?
  
  Yes
  - Repair the Brake Switch (B134) Signal 2 circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace the Brake Switch in accordance with the Service Information. Refer to SWITCH, STOP LAMP, REMOVAL AND INSTALLATION .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK RELATED BCM AND COMPONENT CONNECTIONS
1. Disconnect all BCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Check for spread terminals and verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
10. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL AND INSTALLATION .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - The wiring or poor connection problem has been repaired.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .