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Possible Causes

Circuit open
Circuit shorted
Brake fluid level switch (integral to the brake fluid reservoir)
ABS module

CAUTION:

Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

PINPOINT TEST 8 CHART - DTC C1187: BRAKE FLUID LEVEL INPUT CIRCUIT OPEN

PINPOINT TEST 8		DTC C1187 - BRAKE FLUID LEVEL INPUT CIRCUIT OPEN
STEP	INSPECTION		ACTION
1	CHECK ABS MODULE OPERATION Disconnect: Brake fluid level switch 0413-106. Connect a fused (10A) jumper wire between the brake fluid level switch 0413-106 pin 2, circuit (T/LG), harness side and the brake fluid level switch 0413-106 pin 3, circuit (DG/Y), harness side. Connect: WDS or equivalent tester. Key ON. Using the WDS or equivalent tester, clear the DTCS and repeat the self-test with the brake pedal not applied. Retrieve the DTCs. Is DTC C1187 retrieved again?	Yes	Go to next step.
1		No	Install a new brake fluid reservoir. See BRAKE FLUID RESERVOIR . Clear the DTCs. Repeat the self-test with the brake pedal not applied.
2	CHECK CIRCUIT (T/LG) AND 531 (DG/Y) FOR AN OPEN Key OFF. Disconnect: ABS control module 0413-102. Measure the resistance between: ABS module 0413-102 pin 25, circuit (T/LG), harness side and brake fluid level switch 0413-106 pin 2, circuit (T/LG), harness side. ABS module 0413-102 pin 23, circuit (DG/Y), harness side and brake fluid level switch 0413-106 pin 3, circuit (DG/Y), harness side. Are the resistances less than 5 ohms?	Yes	Go to next step.
2		No	Repair the affected circuit(s) for an open. Clear the DTCs. Repeat the self-test with the brake pedal not applied.
3	CHECK CIRCUIT (T/LG) AND 531 (DG/Y) FOR A SHORT TO GROUND Measure the resistance between ground and: ABS module 0413-102 pin 25, circuit (T/LG), harness side. ABS module 0413-102 pin 23, circuit (DG/Y), harness side. Is the resistance greater than 10,000 ohms?	Yes	Go to next step.
3		No	Repair the affected circuit(s) for a short to ground. Clear the DTCs. Repeat the self-test with the brake pedal not applied.
4	CHECK FOR CORRECT ABS MODULE OPERATION Disconnect all ABS connectors. Check for: corrosion. pushed-out pins. spread terminals. Connect all ABS 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 ABS module. See ANTI-LOCK BRAKE SYSTEM (ABS) MODULE , . Test the system for normal operation.
4		No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. Clear the DTCs. Repeat the self-test with the brake pedal not applied.