Diagnostic Routine A

Diagnostic Routine A

Diagnostic Overview

No Power in All Ignition Switch Positions - Vehicles with an Ignition Switch

Refer to Wiring Diagram Set 13 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

The ignition switch receives fused battery voltage from BCM (Body Control Module) fuse 28 (15A). In the ACC or RUN position, this voltage is sent to the BCM (Body Control Module). In the START position, this voltage is sent to both the BCM (Body Control Module) and the PCM (Powertrain Control Module).

When the ignition switch is cycled to the OFF/LOCK position from any other position the BCM (Body Control Module) begins a monitoring cycle. The monitoring cycle checks that the voltage supplied to the BCM (Body Control Module) from the ignition switch through the RUN/ACC, RUN/START and START circuits is delivered correctly for each ignition switch position.

DTC Fault Trigger Conditions






Visual Inspection and Diagnostic Pre-checks

Make sure the battery and battery cables are OK.

Make sure high current BJB (Battery Junction Box) fuse B (100A) is OK.

Make sure BCM (Body Control Module) fuse 28 (15A) is OK.

Pinpoint Test

1. CHECK THE IGNITION SWITCH

1. Ignition OFF.

2. Disconnect: Ignition Switch.

3. Carry out the Ignition Switch Component Test.

Is the ignition switch OK?








2. CHECK FOR POWER TO THE IGNITION SWITCH

1. Measure:





Is the voltage greater than 11 volts?








3. CHECK FOR POWER TO BCM (Body Control Module) FUSE 28 (15A)

1. Measure:





Is the voltage greater than 11 volts?








4. CHECK FOR CORRECT BCM (Body Control Module) OPERATION

1. Disconnect and inspect all BCM (Body Control Module) connectors.

2. Repair:

- corrosion (install new connector or terminals - clean module pins)
- damaged or bent pins - install new terminals/pins
- pushed-out pins - install new pins as necessary

3. Reconnect the BCM (Body Control Module) connectors and all previously disconnected exterior system connectors. Make sure they seat and latch correctly.

4. Operate the system and determine if the concern is still present.

Is the concern still present?