Pinpoint Test I: The Brake Warning Indicator Is Never On
Instrumentation and Warning Chimes
Pinpoint Tests
Pinpoint Test I: The Brake Warning Indicator Is Never 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 (GN/VT), for brake fluid level concerns. When the parking brake is applied, the IC receives a ground and turns on the brake warning indicator. When the 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.
- DTC C1226 (ABS Warning Lamp Output Circuit Short to Ground) - sets if the IC detects a short to ground on circuit CCA02 (GN/VT) during the IC initiation and bulb check.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Brake fluid level switch
- Parking brake switch
- ABS module
- IC
PINPOINT TEST I: THE BRAKE WARNING INDICATOR IS NEVER ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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I1 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. Observe the brake warning indicator.
- Does the brake warning indicator illuminate when commanded on?
Yes
GO to I2.
No
GO to I11.
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I2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Use the recorded IC DTCs from the self-test.
- Are any DTCs retrieved?
Yes
For DTC C1226, GO to I8.
For all other IC DTCs, REFER to DTC Charts. [1][2]Diagnostic Trouble Code Descriptions
No
If the brake warning indicator does not operate with the parking brake, GO to I3.
If the brake warning indicator does not operate with low brake fluid level, GO to I6.
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I3 CHECK THE PARKING BRAKE INPUT
- Ignition OFF.
- Disconnect: Parking Brake Switch C2015.
- Connect a fused jumper wire between the parking brake switch C2015-1, circuit CCB09 (GY/BU), harness side and the parking brake switch C2015-2, circuit GD175 (BK/BU), harness side.
- Ignition ON.
- Does the brake warning indicator illuminate?
Yes
INSTALL a new parking brake switch. TEST the system for normal operation.
No
REMOVE the jumper wire. GO to I4.
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I4 CHECK CIRCUIT GD175 (BK/BU) FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the parking brake switch C2015-2, circuit GD175 (BK/BU), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to I5.
No
REPAIR the circuit. TEST the system for normal operation.
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I5 CHECK CIRCUIT CCB09 (GY/BU) FOR AN OPEN
- Disconnect: IC C220b.
- Measure the resistance between the IC C220b-20, circuit CCB09 (GY/BU), harness side and the parking brake switch C2015-1, circuit CCB09 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to I11.
No
REPAIR the circuit. TEST the system for normal operation.
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I6 CHECK THE BRAKE FLUID LEVEL SWITCH INPUT
- Ignition OFF.
- Disconnect: Brake Fluid Level Switch C124.
- Ignition ON.
- Does the brake warning indicator illuminate?
Yes
GO to I7.
No
GO to I10.
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I7 CHECK CIRCUIT GD121 (BK/YE) FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the brake fluid level switch C124-1, circuit GD121 (BK/YE), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new brake fluid level switch. TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
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I8 CHECK THE ABS MODULE OPERATION
- Ignition OFF.
- Disconnect: ABS Module C135.
- Ignition ON.
- Does the brake warning indicator stay illuminated after prove-out?
Yes
GO to I10.
No
GO to I9.
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I9 CHECK CIRCUIT CCA02 (GN/VT) FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: IC C220b.
- Measure the resistance between the IC C220b-16, circuit CCA02 (GN/VT), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to I11.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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I10 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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I11 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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