P0572

P0572-BRAKE SWITCH 1 STUCK ON

P0572-Brake Switch 1 Stuck On:

WHEN MONITORED
Ignition on.

SET CONDITION
When the PCM recognizes Brake Switch No.1 is mechanically stuck in the low/on position. Two Trip Fault. Three Global Good Trips to Clear.

POSSIBLE CAUSES
- (B15) Brake switch no.1 signal circuit shorted to ground
- (B16) Brake switch no.2 signal circuit open
- Stop lamp switch
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. ACTIVE DTC

NOTE: Verify battery voltage is greater than 10 volts.

With a scan tool, read DTCs.

Q: Is the DTC active at this time?

YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

2. STOP LAMP SWITCH

Turn the ignition off.
Remove the Stop Lamp Switch and disconnect the harness connector.
Measure the resistance between the (Z940) Ground circuit terminal and the (B15) Brake Switch No.1 Signal terminal in the Stop Lamp Switch.
Measure the resistance between the (F942) Fused Ignition Switch Output circuit terminal and the (B16) Brake Switch No.2 Signal circuit terminal in the Stop Lamp Switch.
Apply and release the Stop Lamp Switch plunger while monitoring the ohmmeter.

Q: Does the resistance change from below 5.0 ohms to an open circuit?

YES: Go To 3
NO: Replace the Stop Lamp Switch. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




3. (B15) BRAKE SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance between ground and the (B15) Brake Switch No.1 Signal circuit in the Stop Lamp Switch harness connector.

Q: 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 4




4. (B16) BRAKE SWITCH NO.2 SIGNAL CIRCUIT OPEN

Measure the resistance of the (B16) Brake Switch No.2 Signal circuit from the Stop Lamp Switch harness connector to the appropriate terminal of special tool #8815.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the open in the (B16) Brake Switch No.2 Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Q: 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. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test