GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) receives a signal from the brake pedal position sensor through the brake pedal sensor signal circuit. The BCM then applies voltage through the stop lamp switch signal circuit to the powertrain control module (PCM).

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0573 Cruise Control Brake Switch Circuit High Voltage

Conditions for Running the DTC

    • Vehicle has cycled from 0-60 km/h (0-37 mph) 3 times in 1 ignition cycle.
    • Continuous once the previous criteria have been met.

Conditions for Setting the DTC

The PCM detects an open or short to ground on the stop lamp switch signal circuit when the voltage should be present.

Action Taken When the DTC Sets

    • The PCM stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

Conditions for Clearing the DTC

    • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Use a scan tool in order to clear the DTC.

Diagnostic Aids

Important: 

   • Verify that the brake pedal position sensor switch is adjusted properly. Refer to Brake Pedal Position Sensor Calibration .
   • Test drive the vehicle if a switch or circuit condition cannot be located. An intermittent condition may be duplicated during a test drive.
   • For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step determines if the fault is present.

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Connect a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Stop Lamp Pedal Switch parameter in the Cruise Control powertrain control module (PCM) Data Display.
  4. Do not press the brake pedal.

Does the Stop Lamp Pedal Switch parameter indicate Unapplied?

Go to Step 3

Go to Diagnostic Aids

3

  1. Disconnect the CHMSL.
  2. Connect a test lamp between the ground circuit of the CHMSL and B+.

Does the test lamp illuminate?

Go to Step 4

Go to Step 6

4

  1. Disconnect the body control module (BCM) connector C1.
  2. Using a test lamp connected to battery positive voltage, probe the stop lamp switch signal circuit.

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5

Test for a short to ground, an open or a poor connection in the stop lamp switch signal circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 8

6

Repair an open or high resistance in the ground circuit of the CHMSL. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 9

--

7

Replace the PCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the repair?

Go to Step 9

--

8

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

9

  1. Use a scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK