Circuit Description
The brake switch indicates brake pedal status to the Powertrain Control Module (PCM). The brake switch is a normally-closed switch that supplies battery voltage on circuit 420 to the PCM. Applying the brake pedal opens the switch, interrupting voltage to the PCM. When the brake pedal is released, the PCM receives a constant voltage signal. If the PCM receives a zero voltage signal at the brake switch input, and the Torque Converter Clutch (TCC) is engaged, the PCM de-energizes the Torque Converter Clutch Solenoid Valve (TCC Sol. Valve).
When the PCM detects an open brake switch circuit (0 volts, low input) during accelerations, then DTC P0719 sets. DTC P0719 is a type D DTC.
Conditions for Setting the DTC
| • | No VSS Assy. DTCs P0502 or P0503. |
| • | The PCM detects an open brake switch circuit (0 volts) for 15 minutes without changing for 2 seconds, and the following events occur seven consecutive times: |
| - | The vehicle speed is less than 8 km/h (5 mph); |
| - | then the vehicle speed is 8-32 km/h (5-20 mph) for 4 seconds; |
| - | then the vehicle speed is greater than 32 km/h (20 mph) for 6 seconds. |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the Malfunction Indicator Lamp (MIL). |
| Important: The following action item will occur before the DTC sets. |
| • | If the PCM detects a continuous open brake switch circuit (0 volts) and does not see it close (12 volts) for 2 seconds, then the brake switch input will be disregarded for TCC scheduling. The following conditions will then dictate TCC scheduling: |
| - | If the TP angle is less than 6% and the vehicle speed is less than 56 km/h (35 mph), then the TCC will not apply. |
| - | If the TP angle is greater than 10% and the vehicle speed is greater than 64 km/h (40 mph), then the TCC may apply and may remain applied until the TP angle falls below 6% or the vehicle speed falls below 56 km/h (35 mph). |
| - | The above conditions may not always be accurate as TCC scheduling may be affected by other factors. |
| • | DTC P0719 stores in PCM history. |
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 condition, massage the wiring harness while watching the test equipment for a change. |
| • | Ask about the customer's driving habits. Ask about unusual driving conditions (e.g. stop and go, expressway, etc.). |
| • | Inspect the brake switch for proper mounting and adjustment. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain OBD System Check | |
2 |
Important: Before clearing the DTC(s), use the scan tool in order to record the Failure Records for reference. Using the Clear Info function will erase the stored Failure Records from the PCM. Is the test lamp ON? | -- | ||
Install a fused jumper from terminal A to terminal B of the brake switch connector. Did the TCC Brake Switch status change from Open to Closed? | -- | |||
4 | Remove the ENG IGN1 fuse. Inspect the fuse for an open. Refer to General Electrical Diagnosis Procedures. Is the fuse open? | -- | ||
5 | Inspect circuit 339 (PNK) for a short to ground. Refer to General Electrical Diagnosis Procedures. Did you find and correct a short to ground condition? | -- | ||
6 | Inspect circuit 420 (PPL) for a short to ground. Refer to General Electrical Diagnosis Procedures. Did you find and correct a short to ground condition? | -- | ||
7 | Replace the brake switch. Refer to Stoplamp Switch Replacement. Is the replacement complete? | -- | -- | |
8 | Inspect circuit 339 (PNK) for an open. Refer to General Electrical Diagnosis Procedures. Did you find and correct an open condition? | -- | -- | |
9 | Inspect circuit 420 (PPL) for an open. Refer to General Electrical Diagnosis Procedures. Did you find and correct an open condition? | -- | ||
10 | Replace the PCM. Refer to PCM/TAC Module Replacement. Is the replacement complete? | -- | -- | |
11 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
