For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
IPC Ignition 1 Voltage | 1 | 1 | -- | -- |
IPC Telltale Circuit Board Service Brake Soon Indicator Signal | 1 | 1 | 1 | -- |
1. Service Brake Soon Indicator Malfunction | ||||
Circuit/System Description
The electronic brake control module (EBCM) illuminates the instrument panel cluster (IPC) service brake soon indicator by applying ground to the lamp.
Diagnostic Aids
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, use the scan tool IPC special function Lamp Test command On and OFF. Observe the IPC service brake soon indicator should turn ON for 3 seconds.
| ⇒ | If the service brake soon indicator does not turn ON, go to circuit/system testing service brake soon indicator inoperative. |
| ⇒ | If the service brake soon indicator does not turn OFF, go to circuit/system testing service brake soon indicator always on. |
Circuit/System Testing (Service Brake Soon Indicator Always ON)
- Ignition OFF, disconnect the EBCM harness terminal 39, Ignition ON, observe the service brake soon indicator illuminating.
- Ignition OFF, disconnect from the IPC tell tale circuit board the harness connector containing the service brake soon indicator signal circuit.
- Ignition ON, Connect a 3A test lamp between the IPC IGN 1 voltage circuit terminal A12 and the service brake soon indicator signal circuit.
- If all circuits test normal, test or replace the EBCM.
| ⇒ | If the service brake soon lamp does not illuminate, test the ignition 1 circuit for an open/high resistance. If the circuit tests normal, test or replace the EBCM. |
| ⇒ | If the test lamp does not illuminate , test the IPC IGN 1 voltage circuit terminal A12 circuit for a open/high resistance. If the circuit tests normal, test or replace the IPC tell tale circuit board. |
| ⇒ | If the test lamp illuminates, test the brake indicator signal circuit for a short to ground. If the circuit tests normal, test or replace the EBCM. |
Circuit/System Testing (Service Brake Soon Indicator Inoperative)
- Ignition OFF, disconnect the EBCM harness serial data circuit terminal 39.
- Ignition ON, Connect a 3A fused jumper wire between the IPC service brake soon indicator signal circuit and ground. Observe the IPC service brake soon indicator.
- If the IPC service brake soon indicator does not illuminate, connect a test lamp between the IPC tell tale circuit board harness containing the service brake soon indicator signal circuit and the IGN 1 voltage circuit. Connect a 3A fused jumper wire between the EBCM service brake soon indicator signal circuit terminal 39 and ground. Observe the test lamp.
- If all circuits test normal, test or replace the EBCM.
| ⇒ | If the IPC service brake soon indicator illuminates, test or replace the EBCM. |
| ⇒ | If the test lamp illuminates, replace the IPC tell tale circuit board. |
| ⇒ | If the test lamp does not illuminate, test for a short to voltage or open/high resistance in the service brake soon indicator signal circuit. If the circuit tests normal, replace the EBCM. |
Repair Instructions
| • | Control Module References for EBCM replacement, setup, and programming |
Repair Verification
- Ignition OFF for 5 seconds, Ignition ON, observe the IPC service brake soon indicator.
- Ignition ON, with the scan tool command the IPC Lamp Test ON and OFF.
| ⇒ | The IPC service brake soon indicator should illuminate for 3 seconds then turn OFF. |
| ⇒ | Service brake soon indicator should turn ON and OFF, if not check Circuit/System Testing. |
