For 1990-2009 cars

### 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 P0562: System Voltage Low

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Signal | P0562 | P0562 | -- | --

### Circuit/System Description

The engine control module (ECM) monitors the ignition voltage on the ignition feed circuit to terminal 39 at the ECM. A system voltage DTC will set whenever the voltage is below a calibrated value.

### Conditions for Running the DTC

Engine running time is greater than 120 seconds.

### Conditions for Setting the DTC

System voltage is between 2.48-10.01 volts.

### Action Taken When the DTC Sets

• | The malfunction indicator lamp MIL will be illuminated after 3 valid driving cycles.

• | The ECM will record operating conditions at the time of the diagnostic failure. This information will be stored in the Freeze Frame and Failure Records buffers.

• | A history DTC is stored.

### Conditions for Clearing The MIL/DTC

• | The MIL will turn OFF after 3 or 4 consecutive driving cycles in which the diagnostic runs without a fault.

• | A history DTC will clear after 40 consecutive warm up cycles without a fault.

• | DTCs can be cleared by using the scan tool.

• | Disconnecting the ECM battery feed for 10 seconds

### Circuit/System Verification

With the scan tool installed, ignition ON and the engine OFF, observe the Ignition 1 Signal parameter in the ECM data list. The Ignition 1 Signal parameter should read 10.5 volts or greater.

### Circuit/System Testing

1. Measure the voltage at the battery terminals and compare it with the Ignition 1 Signal parameter in the ECM data list. Verify that battery and Ignition 1 signal readings do not differ more than 1 volt.

⇒ | If greater than 1 volt test the ignition 1, ground circuits of the ECM for open/high resistance or replace the ECM.

2. Refer to Charging System Test .

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming