ECM

DTC P0562 (ECM)

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC P0562
- System Voltage Low - ECM




Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The engine control module (ECM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.


Conditions for Running the DTC

* The vehicle speed is greater than 8 km/h (5 mph).
* The system voltage is between 9.5-18 volts.



Conditions for Setting the DTC

The ECM detects that the system voltage is less than 10 volts for 5 seconds.


Action Taken When the DTC Sets

* The ECM will command the charge indicator to be illuminated on the instrument panel cluster (IPC).
* The ECM will not illuminate the malfunction indicator lamp (MIL).
* The ECM will store conditions, which were present when the DTC set as Fail Records data only.



Conditions for Clearing the DTC

* The ECM will command the message OFF after one trip in which the diagnostic test has been run and passed.
* The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.



Diagnostic Aids

* A low voltage DTC in multiple modules indicates a concern in the charging system.
* Inspect the ECM gound connection G106 (4.3L LU3) or G103 (all other engines) to ensure that they are clean and tight.



Reference Information
Schematic Reference

* Starting and Charging Schematics (Starting and Charging Schematics)
* Engine Controls Schematics (Electrical Diagrams) 4.3L (LU3)
* Engine Controls Schematics (Electrical Diagrams) 6.6L (LMM)
* Engine Controls Schematics (Electrical Diagrams) all other engines (w/o LU3 or LMM)

Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Engine running, accessories OFF, measure and record the battery voltage at the 12V battery terminals. The voltage should be between 12.6 and 15.0 volts.

• If not within the specified range, refer toCharging System Test (Charging System Test) .

2. Observe the scan tool ECM Ignition 1 Signal parameter. The reading should be between 12.6 and 15.0 volts.



Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the ECM.
2. 2. Ignition OFF and scan tool disconnected, open and close the drivers door, and wait 1 minute. Test for less than 5 ohms between the ground circuit terminals and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the B+ circuit terminals and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminals and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

5. If all circuits test normal, replace the ECM.



Repair Instructions

Perform theDiagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.


Control Module References (Programming and Relearning) for ECM replacement, setup, and programming.