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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2006 🢒 Savana - AWD 🢒 Restraints 🢒 SIR 🢒 DTC P0571

Circuit Description

The cruise/brake switch is a normally closed switch and the stop lamp switch is a normally open switch. When the brake pedal is released, the engine control module (ECM) detects a high voltage signal on the cruise/brake switch signal circuit and a low signal voltage signal on the stop lamp switch signal circuit. When the brake pedal is applied, the cruise/brake switch opens and the stop lamp switch closes. The ECM detects a low voltage signal on the cruise brake switch signal circuit and a high voltage signal on the stop lamp switch signal circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0571 Cruise Control Brake Switch Circuit

Conditions for Running the DTC
    •  DTCs P0717, P0722, and C0161 are not set.
    • The engine speed is greater than 700 RPM.
    • The Traction Control System (TCS) or the Antilock Brake System (ABS) are not active or have not failed.

Conditions for Setting the DTC
    • The ECM detects a transition of the stop lamp switch without detecting a transition of the cruise/brake switch during a deceleration event.
    • This diagnostic run continuously with the ignition ON.

Action Taken When the DTC Sets
    • The ECM stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The ECM records the operating conditions at the time the diagnostic fails. The ECM 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

In order to avoid a misdiagnosis, perform the following:

    • Inspect for proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation .
    • For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections .

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

Connector End View Reference: Lighting Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Stoplamp Pedal Switch parameter in the Cruise Control Data list.

Does the Stoplamp Switch parameter display Released?

Go to Step 3

Go to Step 4

3
  1. Press and hold the brake pedal.
  2. With the scan tool, observe the Stoplamp Pedal Switch parameter.

Does the Stoplamp Pedal Switch parameter display Applied?

Go To Diagnostic Aids

Go to Step 6

4
  1. Turn OFF the ignition.
  2. Disconnect the cruise/brake switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the ignition 1 voltage circuit and a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 11

5
  1. Turn OFF the ignition.
  2. Connect a 3 ampere fused jumper between the ignition 1 voltage circuit and the cruise/brake switch signal circuit.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Stoplamp Pedal Switch parameter.

Does the Stoplamp Pedal Switch parameter display Released?

Go to Step 9

Go to Step 8

6
  1. Turn OFF the ignition.
  2. Disconnect the cruise/brake switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, observe the Stoplamp Pedal Switch parameter.

Does the Stoplamp Pedal Switch parameter display Applied?

Go to Step 9

Go to Step 7

7

Test the cruise/brake switch signal circuit for a short to voltage. Refer Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 10

8

Test the cruise/brake switch signal circuit for the following:

    • Open
    • High resistance
    • Short to ground

Refer Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 10

9

Inspect for poor connections at the harness connector of the cruise/brake switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10

Inspect for poor connections at the harness connector of the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 14

Go to Step 13

11

Repair the following in the ignition 1 voltage circuit.

    • An open
    • A high resistance
    • A short to ground

Refer Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 14

--

12

Replace the cruise/brake switch.

Did you complete the replacement?

Go to Step 14

--

13

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

Did you complete the replacement?

Go to Step 14

--

14
  1. Use a scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

Go to Step 2

System OK