Circuit Description
The body control module (BCM) monitors the brake pedal position sensor. When the brake pedal is applied, the BCM detects a predetermined voltage signal. The BCM sends a GMLAN serial data message to the powertrain control module (PCM) indicating the status of the stop lamps.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The PCM receives an invalid brake pedal status GMLAN serial data message from the BCM. |
| • | This diagnostic runs continuously. |
Action Taken When the DTC Sets
| • | The cruise control system is disabled. |
| • | The PCM stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
| • | Use the scan tool in order to clear the DTC. |
Diagnostic Aids
| • | If an BCM has been replaced, the brake pedal position (BPP) sensor must be calibrated. Refer to Brake Pedal Position Sensor Calibration Description and Operation in Lighting System. |
| • | This DTC may be stored as a history DTC without affecting the operation of the module. If stored only as a history DTC and not retrieved as a current DTC, do not replace the module. |
| • | For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Test Description
The numbers below refer to the step numbers located in the diagnostic table.
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This step is performed in order to confirm that DTC P0703 is current within the ECM.
-
This step is performed in order to correct a BPP sensor that must be calibrated, possibly due to a BCM replacement or for a BPP sensor that is out of adjustment.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Computer/Integrating Systems Connector End Views in Computer/Integrating Systems | |||
1 |
Important: Repair all DTCs related to the stop lamps and to the brake system before performing this table. Did you perform the Vehicle Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Is DTC P0703 current in the powertrain control module (PCM)? | Go to Step 3 | Go to Diagnostic Aids | |
Does the DTC reset? | Go to Step 4 | System OK | |
4 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 6 | Go to Step 5 |
5 |
Important: Program the replacement BCM. The BPP sensor must be calibrated after replacement. Replace the BCM. Refer to Body Control Module Replacement in Computer/Integrating Systems. Did you complete the replacement? | Go to Step 6 | -- |
6 |
Does the DTC reset? | Go to Step 2 | System OK |
