For 1990-2009 cars
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The brake switch reports brake pedal status to the Powertrain Control Module (PCM). The brake switch indicates that the brake pedal is either applied or released. The normally-closed switch supplies battery voltage on circuit 420 to the PCM. Applying the brake pedal opens the brake switch, interrupting voltage to the PCM. When the PCM receives 0 volts at the brake switch input, the PCM turns OFF the TCC Solenoid Valve.

If the PCM detects a closed brake switch (pedal released) during deceleration, then DTC P0724 sets. DTC P0724 is a type D DTC.

### Conditions for Setting the DTC

• | No VSS DTCs P0502 or P0503.

• | The vehicle speed is greater than 32 km/h (20 mph) for 6 seconds;

• | Then the vehicle speed decreases to 8 km/h (5 mph) and takes 4 seconds;

• | Finally, the vehicle speed is less than 8 km/h (5 mph).

• | The above conditions must occur 7 times with the brake switch continuously closed.

### Action Taken When the DTC Sets

The PCM does not illuminate the Malfunction Indicator Lamp (MIL).

### Conditions for Clearing the DTC

• | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

• | The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

### Diagnostic Aids

• | Inspect the wiring at the PCM, the brake switch connector and all other circuit connecting points for the following conditions:

- | A bent terminal

- | A backed out terminal

- | A damaged terminal

- | Poor terminal tension

- | A chafed wire

- | A broken wire inside the insulation

- | Moisture Intrusion

- | Corrosion

• | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

### Test Description

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

1. A Scan Tool display that changes from Applied to Released, when the brake switch is disconnected, indicates a faulty brake switch.

#### DTC P0724 Brake Switch Circuit -- High Input

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls
2 |

1. Install the Scan Tool .
2. With the engine OFF, turn the ignition switch to the RUN position.

Important: Before clearing the DTCs, use the Scan Tool in order to record the Failure Records for reference. The Clear Info function will erase the data.

3. Record the DTC Failure Records, then clear the DTC(s).
4. Select Brake Switch on the Scan Tool .
5. Disconnect the brake switch connector.

Did the brake switch status change from Released to Applied?

--

Go to Step 3

Go to Step 4

3 | Replace the brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Is the replacement complete? | -- | Go to Step 6 | --
4 |

1. Inspect circuit 420 (PPL) for a short to power.

Refer to General Electrical Diagnosis in Wiring Systems.

2. Repair the circuit if necessary.

Refer to Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 6

Go to Step 5

5 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | Go to Step 6 | --
6 | In order to verify your repair, using the Scan Tool , perform the following procedure:

1. Select DTC.
2. Select Clear Info, then clear the DTC(s).
3. Operate the vehicle under the following conditions:

• | Turn the ignition switch to the RUN position.

• | The TCC brake switch must be ON for more than 2 seconds.

4. Select Specific DTC.
5. Enter DTC P0724.

Has the test run and passed?

--

System OK

Go to Step 1