Circuit Description
The stop lamp switch indicates the brake pedal status to the transmission control module (TCM). The brake switch is a normally-closed switch that supplies battery voltage on the stop lamp supply voltage circuit to the TCM. Applying the brake opens the stop lamp switch, interrupting voltage to the TCM. When the brake is released, the TCM receives a constant voltage signal input. If the TCM receives a 0 voltage signal input at the stop lamp supply voltage circuit, and the torque converter clutch (TCC) is engaged, the TCM de-energizes the TCC solenoid valve. The TCM disregards the brake switch input for TCC scheduling if there is a brake switch circuit fault.
When the TCM detects an open circuit in the brake switch or brake switch wiring during decelerations, then DTC P0719 sets. DTC P0719 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0719 Brake Switch Circuit Low Voltage
Conditions for Running the DTC
| • | No Brake Switch DTC P0719. |
| • | No OSS DTCs P0722 or P0723. |
| • | The system voltage is 8-18 volts. |
| • | The TCM detects the brake switch is OFF. |
| • | The vehicle speed 32 km/h (20 mph) or greater for 6 seconds, then is between 40 km/h (25 mph) and 8 km/h (5 mph) for 4.75 seconds, then the vehicle speed is less than 8 km/h (5 mph) for 2 seconds, continuously 8 times once the previous criteria have been met. |
Conditions for Setting the DTC
The TCM detects an open or short to ground on the stop lamp switch signal circuit 8 times during decelerations.
Action Taken When the DTC Sets
| • | The TCM does not request the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
| • | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM records this information as a Failure Record. |
| • | The TCM stores DTC P0719 in TCM history. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
Diagnostic Aids
| • | Inspect the brake switch for proper mounting and operation. |
| • | Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0719. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Important: Before clearing the DTC, use the scan tool in order to record the ECM and TCM Failure Records. Using the Clear Info function erases the Failure Records from the ECM and TCM. Caution: Refer to SIR Caution in the Preface section. Does the test lamp illuminate? | Go to Step 3 | Go to Step 4 |
Connect a fused jumper wire between the battery positive voltage supply and stop lamp supply voltage signal circuits of the stop lamp switch connector. Did the TCC Brake Switch status on the scan tool change from Open to Closed? | Go to Step 9 | Go to Step 7 | |
4 | Inspect the MISC IGN fuse for an open. Refer to Circuit Protection - Fuses . Is the fuse open? | Go to Step 5 | Go to Step 10 |
5 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the battery positive voltage circuit of the brake switch for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 6 |
6 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the stop lamp supply voltage signal circuit of the brake switch for a short to ground between the stop lamp switch and the fuse block-body. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
7 | Inspect the STOP/CHMSL fuse for an open. Refer to Circuit Protection - Fuses . Is the fuse open? | Go to Step 8 | Go to Step 11 |
8 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the stop lamp supply voltage signal circuit for a short to ground between the fuse block-body and TCM. Did you find and correct the condition? | Go to Step 13 | -- |
9 | Replace the brake switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 13 | -- |
10 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the battery positive voltage circuit of the brake switch for an open. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | -- |
11 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the stop lamp supply voltage signal circuit of the brake switch for an open between the stop lamp switch and the fuse block-body or between the fuse block-body and TCM. Refer to Testing for Continuity and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
12 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 13 | -- |
13 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | Go to Step 14 | Go to Step 2 |
14 | With the scan tool, observe the stored information, capture info, and DTC Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK |
