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. |
DTC Descriptor
DTC 049: System Voltage HighCircuit Description
The engine control module (ECM) uses the ignition 1 voltage circuit to monitor system voltage. Voltage that is excessively high can cause damage to components and incorrect input readings.
Conditions for Setting the DTC
The ECM detects a system voltage above 16 volts for more than 5 minutes.
Circuit/System Verification
Engine idling, raise the engine speed to more than 1,500 RPM. Observe the battery voltage parameter with a scan tool. The voltage should be less than 16 volts.
Circuit/System Testing
- Measure the voltage across the negative terminal and the positive terminal of the battery with a DMM.
- Verify that the battery voltage is within 0.5 volt of the battery voltage parameter.
- If all circuits/connections test normal, replace the ECM.
| ⇒ | If the voltage is more then the specified range, repair the generator circuit. If circuit/connections test normal, replace the generator. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming. |
