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 B1527: High Parasitic Load Detected

### Circuit/System Description

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

### Conditions for Running the DTC

The ignition must be in Accessory or Run mode for this code to set.

### Conditions for Setting the DTC

The SOC at key-on is 30 percent lower than when the engine was running and battery drain is more than 2 amps.

### Action Taken When the DTC Sets

There is no battery telltale illuminated or DIC message displayed.

### Conditions for Clearing the DTC

• | The DTC will clear if the fault does not return after 50 consecutive ignition cycles.

• | The DTC will clear when run SOC is greater than or equal to 80 percent.

### Reference Information

#### Schematic Reference

Starting and Charging Schematics

#### Connector End View Reference

Engine Electrical 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

### Circuit/System Verification

Ignition ON, compare the scan tool Prev. State of Charge and Start Up State of Charge parameters. The readings should not differ by more than 30%.

⇒ | If the readings differ by more than 30%, refer to Battery Electrical Drain/Parasitic Load Test .