Diagnostic Instructions
DTC Descriptors
DTC P0719: Brake Switch Circuit Low Voltage
DTC P0724: Brake Switch Circuit High Voltage
Circuit/System Description
The stop lamp switch indicates the brake pedal status to the transmission control module (TCM). The stop lamp switch that supplies voltage to the TCM is a normally open switch. Applying the brake pedal closes the stop lamp switch, supplying a 12
volt signal to the TCM. When the brake pedal is released, the stop lamp switch opens, which results in zero voltage on the signal circuit to the TCM. If the TCM receives a B+ voltage on the signal circuit, and the torque converter clutch (TCC) is engaged,
the TCM de-energizes the TCC solenoid valve and converter clutch operation.
Conditions for Running the DTC
P0719
| • | No brake switch DTC P0719. |
| • | No output speed sensor (OSS) DTCs P0722 or P0723. |
| • | Ignition voltage is between 8-18 volts. |
| • | The TCM detects the brake switch is OFF. |
| • | The vehicle speed is 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. |
P0724
| • | No OSS DTCs P0722 or P0723. |
| • | The vehicle speed is less than 8 km/h (5 mph), then the vehicle speed is between 8 km/h (5 mph) and 40 km/h (25 mph) for 4.75 seconds or less, then the vehicle speed is greater than 40 km/h
(25 mph) for greater than 5 seconds. |
Conditions for Setting the DTC
P0719
The TCM detects an open or short to ground on the stop lamp switch signal circuit for 8 times during vehicle decelerations.
P0724
The TCM detects the brake switch circuit is open 8 times during acceleration cycles and the brake switch voltage is high for 900 seconds (15 minutes) or greater.
Action Taken When the DTC Sets
DTCs P0719 and P0724 are Type C DTCs.
Conditions for Clearing the DTC
DTCs P0719 and P0724 are Type C DTCs.
Diagnostic Aids
| • | Although unlikely, a short to voltage or a short to ground could exist on the signal circuit internal to the engine control module (ECM) or body control module (BCM). |
| • | Inspect the brake switch assembly for proper mounting and operation. |
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Transmission Control Module Scan Tool Information
Special Tools
J 45681
Jumper Harness
Circuit/System Verification
- Ignition ON, verify with a scan tool, the brake switch parameter displays Released with the brake pedal in the released position and the parameter displays Applied, with the brake pedal in the applied position.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, disconnect the stop lamp switch harness connector.
- Ignition ON, test for 11-13 volts on the signal circuit terminal B and ground.
| ⇒ | If not within the specified range, test the signal circuit for a short to ground or an open/high resistance. |
- Ignition OFF, test for infinite resistance between terminal A and terminal B of the stop lamp switch.
| ⇒ | If less than specified value, replace the stop lamp switch. |
- Ignition OFF, test for less than 5 ohms of resistance between terminal A and terminal B of the stop lamp switch, with the brake pedal applied.
| ⇒ | If greater than the specified value, replace the stop lamp switch. |
- Ignition OFF, disconnect the TCM connector.
- Test the 12 volt signal circuit for a short to voltage, short to ground, or an open/high resistance from terminal A of the stop lamp switch to terminal 42 at the TCM.
| ⇒ | If the circuits and connections test normal, replace the TCM. |
Repair Instructions
