Diagnostic Routine K

Diagnostic Routine K

Diagnostic Overview

The Brake Warning Indicator is Never On

Refer to Wiring Diagram Set 60 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

REFER to Brake Warning Indicator , REFER to Parking Brake Position Switch and REFER to Brake Fluid Level Switch .

Visual Inspection and Diagnostic Pre-checks

Inspect the brake fluid level switch for signs of any external damage. Inspect the brake fluid level switch wiring for signs of a pinched harness causing the circuits to short together.

Pinpoint Test

1. RETRIEVE THE RECORDED DTCs (Diagnostic Trouble Codes) FROM THE IPC (Instrument Panel Cluster) SELF-TEST

1. Using a scan tool, perform the IPC (Instrument Panel Cluster) self-test.

Are any DTCs (Diagnostic Trouble Codes) recorded?








2. DETERMINE IF THE BRAKE WARNING INDICATOR OPERATES WITH THE PARKING BRAKE

1. Ignition ON.

2. Apply the parking brake while monitoring the brake warning indicator.

Does the brake warning indicator illuminate with the parking brake applied?








3. CARRY OUT THE IPC (Instrument Panel Cluster) INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL

1. Ignition ON.

2. Using a scan tool, view the IPC (Instrument Panel Cluster) PIDs (Parameter Identifications).

3. Select the IPC (Instrument Panel Cluster) brake warning indicator (PBA_LMP) PID (Parameter Identification). Command the brake warning indicator on and observe the brake warning indicator.

Does the brake warning indicator illuminate when commanded on?








4. CHECK THE PARKING BRAKE WARNING INDICATOR SWITCH PID (Parameter Identification)

1. Using a scan tool, view the BCM (Body Control Module) PIDs (Parameter Identifications).

2. Select the BCM (Body Control Module) parking brake (PARK_BRK_SW) PID (Parameter Identification). Monitor the parking brake PID (Parameter Identification) while applying the parking brake.

Does the PID (Parameter Identification) agree with the parking brake position?








5. CHECK THE PARKING BRAKE POSITION SWITCH

1. Disconnect: Parking Brake Position Switch.

2. Connect a fused jumper wire:





Does the brake warning indicator illuminate?








6. CHECK THE PARKING BRAKE POSITION SWITCH GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:





Is the resistance less than 3 ohms?








7. CHECK THE PARKING BRAKE POSITION SWITCH SIGNAL CIRCUIT FOR AN OPEN

1. Disconnect: BCM (Body Control Module) C2280C.

2. Measure:





Is the resistance less than 3 ohms?








8. CHECK THE BRAKE FLUID LEVEL SWITCH OPERATION

1. Ignition OFF.

2. Disconnect: Brake Fluid Level Switch.

3. Ignition ON.

Does the brake warning indicator illuminate?








9. CHECK THE BRAKE FLUID LEVEL SIGNAL AND RETURN CIRCUITS FOR A SHORT TOGETHER

1. Ignition OFF.

2. Disconnect: BCM (Body Control Module) C2280F.

3. Measure:





Is the resistance greater than 10,000 ohms?








10. CHECK THE BRAKE FLUID LEVEL SWITCH GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:





Is the resistance less than 3 ohms?








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

1. Ignition OFF.

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

3. 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

4. Reconnect the BCM (Body Control Module) connectors. Make sure they seat and latch correctly.

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

Is the concern still present?