C0040-29
C0040-29-BRAKE PEDAL SWITCH-SIGNAL INVALID
Special Tools:
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
When the PCM is sending Signal not available or is not performing the signal Parity or Toggle correctly for the Brake Switch Status signal the ABS module sets DTC C0040-29-BRAKE PEDAL SWITCH-SIGNAL INVALID.
- When Monitored:
Ignition Switch ON.
When Set:
When the Powertrain Control Module (PCM) brake signal is not correct for 300 mSec.
1. CHECK POWERTRAIN CONTROL MODULE (PCM) DTCs
1. With the scan tool, read DTCs in the PCM.
Are there any PCM Stop Lamp Switch related DTCs present?
Yes
- Perform the appropriate diagnostic procedure. Testing and Inspection.
No
- Go To 2
2. (B15) BRAKE SIGNAL 1 CIRCUIT
1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) connector.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool # to perform diagnosis.
3. Using a 12 volt test light connected to 12 volts, check the (B15) Brake Signal 1 circuit at the appropriate terminal of special tool # while pressing and releasing the brake pedal several times.
Does the test light change from illuminated to not illuminated as the brake pedal is pressed and released?
Yes
- Go To 3.
No
- Go To 4
3. (B16) BRAKE SIGNAL 2 CIRCUIT
1. Turn the ignition on.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool # to perform diagnosis.
2. Using a 12 volt test light connected to ground, check the (B16) Brake Signal 2 circuit at the appropriate terminal of special tool # while pressing and releasing the brake pedal several times.
Does the test light change from illuminated to not illuminated as the brake pedal is pressed and released?
Yes
- Go To 11
No
- Go To 7
4. (Z916) GROUND CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the Stop Lamp Switch connector.
3. Using a 12 volt test light connected to 12 volts, check the (Z916) Ground circuit in the Stop Lamp Switch harness connector.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test light illuminated and bright?
Yes
- Go To 5
No
- Repair the (Z916) Ground circuit for an open circuit or high resistance.
- Perform the PCM Verification Test. Powertrain Verification Test
5. (B15) BRAKE SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO GROUND
1. Turn the ignition off.
2. Disconnect the C3 PCM harness connector.
3. Measure the resistance between ground and the (B15) Brake Switch No.1 Signal circuit in the Stop Lamp Switch harness connector.
Is the resistance below 100 Ohms?
Yes
- Repair the short to ground in the (B15) Brake Switch No.1 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 6
6. (B15) BRAKE SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool # to perform diagnosis.
1. Measure the resistance of the (B15) Brake Signal 1 circuit between the Stop Lamp Switch harness connector and the appropriate terminal of special tool #.
Is the resistance below 5.0 ohms?
Yes
- Go To 10
No
- Repair the (B15) Brake Signal 1 circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.
7. (F941) FUSED IGNITION SWITCH OUTPUT (RUN-START) CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the Stop Lamp Switch connector.
3. Turn the ignition on.
4. Using a 12 volt test light connected to ground, check the (F941) Fused Ignition Switch Output (Run-Start) circuit in the Stop Lamp Switch harness connector.
NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.
Is the test light illuminated and bright?
Yes
- Go To 8
No
- Repair the (F941) Fused Ignition Switch Output (Run-Start) circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.
8. (B16) BRAKE SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage of the (B16) Brake Signal 2 circuit in the Stop Lamp Switch harness connector.
Is there any voltage present?
Yes
- Repair the (B16) Brake Signal 2 circuit for a short to voltage.
- Perform the PCM Verification Test.
No
- Go To 9
9. (B16) BRAKE SWITCH NO.2 SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the PCM Pinout Box to perform diagnosis.
1. Measure the resistance of the (B16) Brake Switch No.2 Signal circuit from the Stop Lamp Switch harness connector to the appropriate terminal of PCM Pinout Box.
Is the resistance below 5.0 Ohms?
Yes
- Go To 10
No
- Repair the open in the (B16) Brake Switch No.2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
10. STOP LAMP SWITCH
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.
4. Search for any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test.
No
- Replace the Stop Lamp Switch.
- Perform the PCM Verification Test.
11. 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 Powertrain 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. Powertrain Verification Test.
No
- Replace and program the Powertrain Control Module. Powertrain Control Module - Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.