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 relay control 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 zero voltage signal input at the stop lamp relay control 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 brake switch circuit, 0 volts, low input, during accelerations, DTC P0719 will set. 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
| • | DTCs P0722 or P0723 must not be set as current. |
| • | DTC P0724 must not be set as current. |
| • | With the brake switch high and vehicle speed less than 8 km/h (5 mph) then vehicle speed is greater than 8 km/h (5 mph), but less than 40 km/h (25 mph) for less than or equal to 6 seconds, then vehicle speed is greater than 40 km/h (25 mph) for 7 seconds. |
Conditions for Setting the DTC
The TCM detects an open or short to ground on the stop lamp switch signal circuit when the circuit should have battery voltage present.
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 present when the Conditions for Setting the DTC are met. The TCM records this information as a failure record. |
| • | The TCM stores DTC P0719 to memory. |
Conditions for Clearing the DTC
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 40 malfunction-free ignition cycles have occurred. |
Diagnostic Aids
| • | Verify that the brake pedal position sensor is properly calibrated. Refer to Brake Pedal Position Sensor Calibration . |
| • | Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List in Wiring Systems | |||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||
2 |
Does the Stop Lamp Pedal Switch parameter indicate Closed? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | ||||||
3 |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 4 | ||||||
4 | Locate and repair an open or short to ground in the stop lamp switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 | ||||||
5 | Inspect for poor connections at the harness connector of the TCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 | ||||||
6 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | ||||||
7 | Replace the TCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- | ||||||
8 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- | ||||||
9 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | System OK | Go to Step 2 | ||||||
