P0572

P0572-BRAKE SWITCH 1 STUCK ON





For a complete wiring diagram consult Diagrams/Electrical


- When Monitored:
With the gear selector in drive, vehicle speed above a minimum value, and battery voltage greater than 10.4 volts.

- Set Condition:
The PCM detects that the actual state of Brake Signal 1 or Brake Signal 2 does not match the desired state during monitoring.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview


Diagnostic Test


1. DTC IS ACTIVE
Turn the ignition on.
With the scan tool, monitor the Brake Signal 1 and Brake Signal 2 states while pressing and releasing the brake pedal several times.
Do the Brake Signal states change appropriately as the pedal is pressed and released?

Yes


- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking For An Intermittent DTC


No


- Go to 2




2. (B15) BRAKE SIGNAL 1 CIRCUIT




Turn the ignition off.
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 #8815 to perform diagnosis.

Using a 12 volt test light connected to 12 volts, check the (B15) Brake Signal 1 circuit at the appropriate terminal of special tool #8815 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




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 #8815 to perform diagnosis.

Using a 12 volt test light connected to ground, check the (B16) Brake Signal 2 circuit at the appropriate terminal of special tool #8815 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. (Z912) GROUND CIRCUIT OPEN OR HIGH RESISTANCE




Turn the ignition off.
Disconnect the Stop Lamp Switch connector.
Using a 12 volt test light connected to 12 volts, check the (Z912) 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 (Z912) Ground circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test




5. (B15) BRAKE SIGNAL 1 CIRCUIT SHORTED TO GROUND




Measure the resistance between ground and the (B15) Brake Signal 1 circuit in the Stop Lamp Switch harness connector.
Is the resistance above 100 ohms?

Yes


- Go to 6


No


- Repair the (B15) Brake Signal 1 circuit for a short to ground.
- Perform the PCM Verification Test.Powertrain Verification Test




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 #8815 to perform diagnosis.

Measure the resistance of the (B15) Brake Signal 1 circuit between the Stop Lamp Switch harness connector and the appropriate terminal of special tool #8815.
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.Powertrain Verification Test




7. (F202) FUSED IGNITION SWITCH OUTPUT (RUN-START) CIRCUIT OPEN OR HIGH RESISTANCE




Turn the ignition off.
Disconnect the Stop Lamp Switch connector.
Turn the ignition on.
Using a 12 volt test light connected to ground, check the (F202) 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 (F202) Fused Ignition Switch Output (Run-Start) circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test




8. (B16) BRAKE SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE




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.Powertrain Verification Test


No


- Go to 9




9. (B16) BRAKE SIGNAL 2 CIRCUIT OPEN OR HIGH RESISTANCE




Turn the ignition off.

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 #8815 to perform diagnosis.

Measure the resistance of the (B16) Brake Signal 2 circuit between the Stop Lamp Switch harness connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?

Yes


- Go to 10


No


- Repair the (B16) Brake Signal 2 circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test




10. STOP LAMP SWITCH
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes


- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Replace the Stop Lamp Switch.
- Perform the PCM Verification Test.Powertrain Verification Test




11. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Stop Lamp Switch and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes


- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test


No


- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test.Powertrain Verification Test