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 B1517 5A: Battery Voltage Plausibility Failure

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
BCM 2 B+ | B1517 5A | B1325 03, B1517 5A | -- | --
SDM or XM/ONSTAR B+ | B1517 5A | B1517 5A | -- | --
Ground | -- | B1517 5A | -- | --

### Typical Scan Tool Data

#### Battery Voltage Signal - BCM

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Key On, Engine Off. Parameter Normal Value: 12.60 Volts
BCM 2 B+ | 0.00 Volts* | 0.00 Volts* | 12.60 Volts
*The BCM, EBCM, ECM, IPC, PSCM, TCM and TDM will not communicate if there is 0 volts on this circuit.

#### Battery Voltage High Res. - BCM

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Key On, Engine Off. Parameter Normal Value: 12.600 Volts
SDM or XM/ONSTAR B+ | 0.000 Volts* | 0.000 Volts* | 12.600 Volts
*The DRR and VCIM will not communicate if there is 0 volts on this circuit.

### Circuit/System Description

The body control module (BCM) has designated B+ circuits for monitoring vehicle system voltage, fed by the BCM 2 fuse and the SDM or XM/ONSTAR fuse. Fuse 24 in the BCM will either be labeled SDM or XM/ONSTAR, depending on vehicle content. 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 3 volts, DTC B1517 5A will set. Other modules also monitor system voltage. The system voltage message is sent to the other modules and will default to 12.9 volts if DTC B1517 5A sets.

### Conditions for Running the DTC

• | The BCM has power and ground

• | The ignition switch is not in the start position

### Conditions for Setting the DTC

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

### Action Taken When the DTC Sets

The regulated voltage control (RVC) is disabled.

### Conditions for Clearing the DTC

• | The DTC will pass when the condition for setting the DTC is no longer present.

• | A history DTC will clear after 50 consecutive ignition cycles have occurred without a malfunction.

### Diagnostic Aids

• | A low voltage DTC in multiple modules indicates a concern in the charging system.

• | Inspect the SDM or XM/ONSTAR fuse for an open.

### Reference Information

#### Schematic Reference

• | Starting and Charging Schematics

• | Body Control System Schematics

• | Power 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, and should be within 2 volts of each other.

### Circuit/System Testing

1. Verify that a test lamp illuminates between the SDM or XM/ONSTAR fuse 24 in the BCM and ground.

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

2. Ignition OFF, disconnect the harness connectors at the BCM.
3. Test for less than 5 ohms between the ground circuit terminal E12 X4 and ground.

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

4. Verify that a test lamp illuminates between the B+ circuit terminals listed below and ground.

• | Terminal D1 X3

• | Terminal D12 X3

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

5. Test for less than 5 ohms between the B+ circuit terminal 62 X1 and terminal B3 X3.

⇒ | If greater than the specified range, test the B+ circuit for an open/high resistance.

6. If all circuits test normal, replace the BCM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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