Chevrolet Silverado / GMC Sierra. Service manual — part 1691

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 Descriptors

DTC B1517 03

Battery Voltage Below Threshold - BCM

DTC B1517 07

Battery Voltage Above Threshold - BCM

DTC B1517 5A

Battery Voltage Plausibility Failure - BCM

Diagnostic Fault Information

Circuit/System Description

The body control module (BCM) has circuits for monitoring vehicle system voltage. The BCM
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. The BCM monitors
the system voltage over an extended length of time. If the BCM detects the system voltage is
outside an expected range for the calibrated length of time, or the BCM battery sense circuits
differ by 2 volts, DTC B1517 will set. The system voltage message is sent to the other modules.
The message will default to 12.9 volts if there is a plausibility failure.

Conditions for Running the DTC

The BCM has power and ground.

Circuit

Short to

Ground

Open/High

Resistance

Short to

Voltage

Signal

Performance

B+

B1517 03,

B1517 5A

B1517 03,

B1517 5A

-

-

Ground

-

B1517 03,

B1517 5A

-

-

2008 Chevrolet Silverado 1500

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

The ignition is not in the START position.

Conditions for Setting the DTC

B1517 03

The battery voltage is less than 11 volts.

The engine speed is greater than 1,100 RPM.

The above conditions are met for 15 seconds.

B1517 07

The battery voltage is greater than 16 volts.

The engine speed is greater than 1,100 RPM.

The above conditions are met for 15 seconds.

B1517 5A

The voltage of the two BCM battery sense circuits differs by 2 volts for 10 seconds.

Action Taken When the DTC Sets

The instrument panel cluster (IPC) illuminates the charge indicator.

The driver information center (DIC) displays the SERVICE BATTERY CHARGING
SYSTEM message.

Conditions for Clearing the DTC

The DTC will clear current status when fault is no longer present.

The history DTC will clear after 50 consecutive ignition cycles have occurred without a
malfunction.

Diagnostic Aids

A high or low voltage DTC in multiple modules indicates a concern in the charging system.
Refer to Charging System Test.

Inspect the ground connections G103 and G201, and insure that they are clean and tight.

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

Reference Information

2008 Chevrolet Silverado 1500

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

Schematic Reference

Body Control System Schematics

Power Distribution Schematics

Ground Distribution Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Charging System Description and Operation

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. Engine running, accessories OFF, measure and record the battery voltage at the battery

terminals. The voltage should be between 12.6 and 15.0 volts.

If not within the specified range, refer to Charging System Test.

2. Observe the scan tool BCM Battery Voltage Signal parameter and the Batt. Voltage High

Res. parameter. The reading for both parameters should be between 12.6 and 15.0 volts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connectors at the BCM.

2. Ignition OFF, test for less than 5 ohms between the ground circuit terminals listed below

and ground.

Terminal 1 X3

Terminal 5 X3

2008 Chevrolet Silverado 1500

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

Terminal 9 X4

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 listed below and ground.

Terminal 3 X3

Terminal 10 X4

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

4. If all circuits tests normal, replace the BCM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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

DTC B1527

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 B1527 00

High Parasitic Load

Circuit/System Description

The body control module (BCM) monitors the state of charge (SOC) of the electrical system. If
the BCM senses that the current draw was greater than 2 amps and the SOC at key-on is 30
percent lower than it was when the engine was last running, DTC B1527 00 will set.

Conditions for Running the DTC

The ignition is turned from Off to Accessory or Run.

Conditions for Setting the DTC

2008 Chevrolet Silverado 1500

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