GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 Vibe - AWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0724

Circuit Description

The purpose of this circuit it to prevent the engine from stalling while driving in lock-up condition when brakes are suddenly applied. When the brake pedal is depressed, this switch sends a signal to the engine control module (ECM). The ECM then cancels the operation of the lock-up clutch while braking is in progress.

This DTC indicates that the stop light switch remains ON. When the stop light remains ON during "stop and go" driving, the engine control module (ECM) interprets this as a fault in the stop light switch and the MIL comes on and the ECM stores the DTC.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0724 Brake Switch"B" Circuit High

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The ECM will set the DTC if the stops at less than 3 km/h (2 mph) and goes 30 km/h (19 mph) or more 5 times for two driving cycles.

Action Taken When the DTC Sets
    • DTC P0724 is a type C DTC.
    • The malfunction indicator lamp (MIL) illuminates the first time the diagnostic runs with the fault active.

Conditions for Clearing the MIL/DTC

The DTC will clear when conditions for setting the DTC have been repaired.

Step

Action

Values

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install a scan tool.
  2. Turn ON the engine.
  3. Select the brake switch parameter on the scan tool.

Does the brake switch parameter change from depressed to released as the brake pedal is depressed and released?

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Refer to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  1. Turn the ignition to OFF.
  2. Remove the stop light switch assembly.
  3. Measure the resistance as follows:
    4. • Between terminals 1 and 2 with switch pin free.
    • Between terminals 1 and 2 with switch pin pushed in.
    • Between terminals 3 and 4 with switch pin free.
    • Between terminals 3 and 4 with switch pin pushed in.

Is the resistance measured within specified value?

Between terminals 1 and 2 or 3 and 4 with switch pin free = Below 1 Ohm

Between terminals 1 and 2 or 3 and 4 with switch pin pushed in = 10 Kohms or higher

Go to Step 4

Go to Step 6

4
  1. Install the stop light switch assembly.
  2. Disconnect the ECM connector A21.
  3. Turn the ignition ON, with the engine OFF.
  4. Measure the voltage as follows:
    5. • Between connector A21 terminal 36 and body ground with brake pedal depressed.
    • Between connector A21 terminal 36 and body ground with brake pedal released.

Is the voltage measured within specified value?

With brake pedal depressed = 11 to 14 Volts

With brake pedal released = Below 10 Kohms

Go to Step 7

Go to Step 5

5

Repair or replace harness or connector of the ECM. Refer to Wiring Repairs and Connector Repairs .

Did you complete the repair or replacement?

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Go to Step 8

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6

Replace the stop light switch assembly. Refer to Stop Lamp Switch Replacement .

Did you complete the replacement?

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Go to Step 8

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7

Replace the ECM. Refer to Control Module References .

Did you complete the replacement?

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Go to Step 8

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8
  1. Use the scan tool in order to clear the DTC.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

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Go to Step 2

System OK