Pinpoint Test J: The Brake Warning Indicator Is Always On
Instrumentation and Warning Chimes
Pinpoint Tests
Pinpoint Test J: The Brake Warning Indicator Is Always On
Refer to wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number
Normal Operation
The brake warning light is used to indicate low fluid level (base brake system concern) or a parking brake that is not fully released. The Instrument Cluster (IC) is hardwired to the parking brake switch through circuit CCB09 (GY/BU) for parking brake status. The IC is hardwired to the ABS module through the electronic brake distribution (EBD) line, circuit CCA02 (BK/BU), for brake fluid level concerns. When the parking brake is applied, the IC receives a ground and turns on the brake warning indicator. When brake fluid is low or the ABS module detects a base brake system concern, the ABS module sends the IC a signal through the EBD line and the IC turns on the brake warning indicator. If the IC detects a fault condition in either the base brake system (low brake fluid level) or ABS, both the brake and ABS warning indicators are turned on.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Parking brake switch
- ABS module
- IC
PINPOINT TEST J: THE BRAKE WARNING INDICATOR IS ALWAYS ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Verify that the brake fluid level is full and the parking brake is fully released before continuing with diagnostics.
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J1 CARRY OUT THE IC INDICATOR LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC brake warning indicator (BRK_LAMP) active command. Command the brake warning indicator on then off again. Observe the brake warning indicator.
- Does the brake warning indicator turn off when commanded off?
Yes
GO to J2.
No
GO to J11.
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J2 RETRIEVE THE RECORDED DTCs FROM THE ABS MODULE SELF-TEST
- Use the recorded ABS module DTCs from the self-test.
- Are any DTCs retrieved?
Yes
REFER to Antilock Brakes / Traction Control Systems. Testing and Inspection
No
GO to J3.
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J3 DETERMINE THE CONDITION
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC parking brake PID (PRKSWAPPL). Apply and release the parking brake while monitoring the IC parking brake switch PID.
- Does the PID agree with the parking brake position?
Yes
GO to J6.
No
GO to J4.
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J4 CHECK THE PARKING BRAKE SWITCH
- Ignition OFF.
- Disconnect: Parking Brake Switch C2015.
- Ignition ON.
- Observe the brake warning indicator.
- Did the brake warning indicator turn off?
Yes
INSTALL a new parking brake switch. TEST the system for normal operation.
No
GO to J5.
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J5 CHECK CIRCUIT CCB09 (GY/BU) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC C220b.
- Measure the resistance between the parking brake switch C2015-1, circuit CCB09 (GY/BU), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to J11.
No
REPAIR the circuit. TEST the system for normal operation.
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J6 CHECK THE BRAKE FLUID LEVEL SWITCH
- Ignition OFF.
- Disconnect: Brake Fluid Level Switch C124.
- Connect a fused jumper wire between the brake fluid level switch C124-2, circuit CMC19 (GY/VT), harness side and the brake fluid level switch C124-3, circuit RMC19 (YE/GY), harness side.
- Ignition ON.
- Monitor the brake warning indicator.
- Does the brake warning indicator turn off?
Yes
REMOVE the jumper wire. INSTALL a new brake fluid level switch. TEST the system for normal operation.
No
REMOVE the jumper wire. GO to J7.
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J7 CHECK THE ABS MODULE OPERATION
- Ignition OFF.
- Disconnect: ABS Module C135.
- Connect a fused jumper wire between the ABS module C135-27, circuit CCA02 (GN/VT), harness side and ground.
- Ignition ON.
- Does the brake warning indicator turn off?
Yes
REMOVE the jumper wire. GO to J9.
No
REMOVE the jumper wire. GO to J8.
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J8 CHECK CIRCUIT CCA02 (GN/VT) FOR AN OPEN
- Ignition OFF.
- Disconnect: IC C220b.
- Measure the resistance between the ABS module C135-27, circuit CCA02 (GN/VT), harness side and the IC C220b-16, circuit CCA02 (GN/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to J11.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the on-demand self-test.
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J9 CHECK CIRCUITS CMC19 (GY/VT) AND RMC19 (YE/GY) FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the ABS module C135-25, circuit CMC19 (GY/VT), harness side and ground; and between the ABS module C135-23, circuit RMC19 (YE/GY), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to J10.
No
REPAIR the circuit in question. TEST the system for normal operation.
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J10 CHECK FOR CORRECT ABS MODULE OPERATION
- Disconnect the ABS module connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the ABS module connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ABS module. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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J11 CHECK FOR CORRECT IC OPERATION
- Disconnect all the IC connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the IC connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation.
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