Pinpoint Test O : The Brake Warning Indicator Is Never On
- Instrument Cluster for schematic and connector information.
Normal Operation and Fault Conditions
See Brake Warning Indicator and see Brake Fluid Level Switch component description. REFER to: Instrument Panel Cluster (IPC) - System Operation and Component Description .
If the brake (red) warning indicator request or brake warning indicator request messages are missing or invalid for less than 5 seconds, the IPC defaults the ABS warning indicator to the last indication state (on or off), based upon the last message received.
Possible Sources
- Brake fluid level switch
- Parking brake switch
- BCM
- IPC
Visual Inspection and Pre-checks
- Inspect the brake fluid level switch for signs of any external damage.
- Inspect the wiring harness for signs of a pinched harness causing a shorted circuit.
- O1 PERFORM THE IPC (INSTRUMENT PANEL CLUSTER) INDICATOR LAMP CONTROL ACTIVE COMMAND USING A DIAGNOSTIC SCAN TOOL
- Ignition ON.
- Using a diagnostic scan tool, view the IPC Parameter Identifications (PIDs).
- Select the IPC brake warning indicator (PBA_LMP) PID.
- Command the brake warning indicator on then off. Observe the brake warning indicator.
Does the brake warning indicator turn on when commanded on and turn off when commanded off?
Yes GO to O2 No INSTALL a new IPC. REFER to: Instrument Panel Cluster (IPC) . - O2 DETERMINE IF THE BRAKE WARNING INDICATOR OPERATES WITH THE PARKING BRAKE APPLIED
- Apply the parking brake while monitoring the brake warning indicator.
Does the brake warning indicator illuminate?
Yes GO to O5 No GO to O3 - O3 CHECK THE PARKING BRAKE POSITION SWITCH
- Ignition OFF.
- Disconnect Parking Brake Position Switch C306.
- Connect a fused jumper wire:
Lead 1 Measurement / Action Lead 2 Refer to C306-1 Ground
- Ignition ON.
Does the brake warning indicator illuminate?
Yes REMOVE the fused jumper wire. INSTALL a new parking brake position switch. No REMOVE the fused jumper wire. GO to O4 - O4 CHECK THE PARKING BRAKE WARNING INDICATOR SIGNAL CIRCUIT FOR AN OPEN
- Disconnect BCM C2280F.
Is the resistance less than 3 ohms?
Yes GO to O6 No REPAIR the circuit. - O5 CHECK THE BRAKE FLUID LEVEL SWITCH OPERATION
- Ignition OFF.
- Disconnect Brake Fluid Level Switch C124.
- Ignition ON.
- Wait one minute.
Does the brake warning indicator illuminate?
Yes VERIFY the brake fluid level is low enough to turn on the brake warning indicator or has been reported low enough to turn on the brake warning indicator. If the brake fluid level is currently low or has been reported low, INSTALL a new brake fluid level switch. If the brake fluid level is not currently low or has not been reported low, the system is operating correctly at this time. No GO to O6 - O6 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION
- Ignition OFF.
- Disconnect and inspect the BCM and all related in-line connectors.
- 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
- Reconnect the BCM and all related in-line connectors. Make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new BCM. REFER to: Body Control Module (BCM) . No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.