P0572-BRAKE SWITCH 1 STUCK ON





For a complete wiring diagram Refer to Section 8W.



Possible Causes
(B15) BRAKE SIGNAL 1 CIRCUIT SHORTED TO GROUND
(B16) BRAKE SIGNAL 2 CIRCUIT OPEN
STOP LAMP SWITCH
PCM


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1. ACTIVE DTC

NOTE: Verify battery voltage is greater than 10 volts.


Start the engine.
Allow the engine to reach normal operating temperature.
With a scan tool, select View DTCs.

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.



Is the DTC Active or Pending at this time?

Yes


No

2. STOP LAMP SWITCH

Turn the ignition off.
Remove the Stop Lamp Switch and disconnect the harness connector.
Measure the resistance between the (Z914) Ground circuit terminal and the (B15) Brake Signal 1 circuit terminal in the Stop Lamp Switch.
Measure the resistance between the (F941) Fused Ignition Switch Output circuit terminal and the (B16) Brake Signal 2 circuit terminal in the Stop Lamp Switch.
Apply and release the Stop Lamp Switch plunger while monitoring the ohmmeter.

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

Yes


No

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



Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance between ground and the (B15) Brake Signal 1 circuit in the Stop Lamp Switch harness connector.

Is the resistance below 100 ohms?

Yes


No

4. (B16) BRAKE SIGNAL 2 CIRCUIT OPEN


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 from the Stop Lamp Switch harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

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.

Were there any problems found?

Yes


No