Diagnostic Instructions
DTC Descriptor
DTC P0719 00: Brake Switch Circuit Low Voltage
Circuit/System Description
The cruise release switch is a normally closed switch. The stop lamp switch signal circuit is a normally open switch. When the brake pedal is released, the engine control module (ECM) detects a high voltage signal on the torque converter clutch (TCC) brake
switch/cruise control release signal circuit and a low signal voltage signal on the stop lamp switch signal circuit.
Conditions for Running the DTC
| • | The traction control system or the antilock brake system are not active and have not failed. |
| • | The vehicle has accelerated from 0 km/h (0 mph) to 60 km/h (37 mph) 3 times in one ignition cycle. |
| • | This diagnostic runs continuously once the conditions for running the DTC has been achieved. |
Conditions for Setting the DTC
When the brake pedal is released, the ECM detects a low voltage signal on the stop lamp switch signal circuit and a low voltage signal on the TCC brake switch/cruise control release signal circuit.
Action Taken When the DTC Sets
| • | The ECM stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
| • | The Cruise Control System is disabled. |
Conditions for Clearing the DTC
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Use a scan tool in order to clear the DTC. |
Diagnostic Aids
In order to avoid a misdiagnosis, inspect for proper adjustment of the cruise control release switch. Refer to
Cruise Release Switch Adjustment
.
For an intermittent condition, refer to
Testing for Intermittent Conditions and Poor Connections
.
Reference Information
Schematic Reference
Cruise Control Schematics
Connector End View Reference
Lighting Systems Connector End Views
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the Stop Lamp/TCC Cruise Release Switch.
- Ignition ON, test for B+ between the HVAC I/P IGN voltage circuit terminal A and ground.
| ⇒ | If less than the specified voltage, test the voltage circuit for an open/high resistance, or a short to ground. |
- Ignition OFF, connect the harness connector at the Stop Lamp/TCC Switch. Disconnect the harness connector C1 at the ECM.
- With the Stop Lamp/TCC Switch closed, test for B+ between the TCC Brake Switch/Cruise Control Release Signal circuit and ground.
| ⇒ | If less than the specified voltage, test the signal circuit for an open/high resistance, or a short to ground. If the circuit tests normal, replace the Stop Lamp/TCC Switch. |
- If all circuits test normal, test or replace the ECM.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
