Chevrolet Silverado / GMC Sierra. Service manual — part 1694

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 a system voltage 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 insure
that they are clean and tight.

Reference Information

Schematic Reference

Starting and Charging Schematics

Engine Controls Schematics 4.3L (LU3)

Engine Controls Schematics 6.6L (LMM)

Engine Controls Schematics all other engines (w/o LU3 or LMM)

Connector End View Reference

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Component Connector End Views

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Verification

1. Ignition On. Measure and record the voltage at the battery terminals. Verify that the battery

voltage is 12-17 volts. Repeat with the engine running.

If the battery voltage is not within the specified range, go to Charging System Test.

2. Engine running. Observe the Ignition 1 Signal parameter in the ECM scan tool data list.

Verify that the scan tool displays a value that is within 1 volt of the battery voltage recorded
in step 1.

If the scan tool parameter is not within the specified range, go to Circuit/System
Testing.

3. Go to Diagnostic Aids.

Circuit/System Testing

1. Ignition OFF. Disconnect the harness connector of the ECM.

2. Probe the ground circuits with a test lamp that is connected to B+. The test lamp should

illuminate.

If the test lamp does not illuminate, then test the ground circuit for an open/high
resistance.

3. Test for 11-14 volts between the battery positive voltage and the ground circuits of the

ECM.

If not within the specified range, test the battery positive voltage circuits for a short to
ground or an open/high resistance.

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

Repair Procedures

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming.

DTC P0563

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 P0563

System Voltage High

Diagnostic Fault Information

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 a system voltage above 16 volts for 1 second.

Action Taken When the DTC Sets

The ECM will command the charge indicator to be illuminated on the instrument panel

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

B+

P0562

P0562

-

-

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

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 indicator OFF after one trip in which the diagnostic test has
been run and passed.

A history DTC will clear after 40 consecutive warm-up cycles have occurred without a
malfunction.

Reference Information

Starting and Charging Schematics

Engine Controls Schematics 4.3L (LU3)

Engine Controls Schematics 6.6L (LMM)

Engine Controls Schematics all other engines (w/o LU3 or LMM)

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Diagnostic Aids

This DTC could be set by overcharging with a battery charger or jump starting.

A high voltage DTC in multiple modules indicates a concern in the charging system.

Circuit/System Verification

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado