P0572
P0572-LOW VOLTAGE DETECTED AT THE BRAKE SWITCHP0572 - Low Voltage Detected At The Brake Switch:
WHEN MONITORED
While the ignition is on
SET CONDITION
The brake switch status is = to OFF and the not brake switch status is = to ON for a calibrated amount of time.
POSSIBLE CAUSES
- Damaged wiring harness or connectors
- Brake switch circuit shorted to ground (brake switch will always be off)
- Brake switch
- ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
1. BRAKE SWITCH CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the brake switch connection. Inspect the pins and connector for damage, corrosion, etc.
Disconnect the ECM connectors. Inspect the pins and connector for damage, corrosion, etc.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the brake switch circuit in the ECM connector and battery negative.
Q: Is the resistance less than 10 ohms?
YES: Repair the Brake switch circuit shorted to ground. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 2
2. BRAKE SWITCH CIRCUIT SHORTED TO OTHER CIRCUITS IN HARNESS
Measure the resistance between the brake switch wire in the ECM connector and all other pins in the ECM connector.
Q; Is the resistance less than 10 ohms?
YES: Repair or replace the harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 3
3. ECM
Reconnect the ECM connectors.
Measure the resistance between the brake switch circuit at the switch connector and battery negative.
Q: Is the resistance less than 10 ohms?
YES: Replace the ECM. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 4
4.
Reconnect the brake switch connector.
Using the scan tool, clear the DTC's.
Turn the ignition on.
Cycle the brake pedal several times.
Using the scan tool, read the DTC's.
Q: Has the brake switch low DTC returned?
YES: Replace the brake switch. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Perform Intermittent condition test.