Pinpoint Test K: The Brake Warning Indicator Is Never On
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test K: The Brake Warning Indicator Is Never On
Refer to Wiring Diagram Set 60 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Instrument Cluster for schematic and connector information. Diagrams By Number
Normal Operation
The Instrument Cluster (IC) uses 3 basic messaged inputs to control the brake warning indicator. The first 2 are the parking brake warning indicator switch and the brake fluid level switch. The third is for the Electronic Brake Distribution (EBD), controlled by the ABS module. The parking brake warning indicator switch and the brake fluid level switch status are sent from the Smart Junction Box (SJB) over the Medium Speed Controller Area Network (MS-CAN) communication bus. The EBD message is sent from the ABS module over the High Speed Controller Area Network (HS-CAN) communication bus lines. The parking brake warning indicator switch and the brake fluid level switch are hardwired to the SJB through separate signal and return circuits.
The SJB provides a reference voltage to both the parking brake warning indicator switch and the brake fluid level switch. When the parking brake is applied, the parking brake warning indicator switch closes to ground, providing a ground to the SJB and pulling the signal circuit low. When a low brake fluid level condition exists, the low brake fluid level switch closes to ground, pulling the signal circuit low. The SJB monitors the parking brake and the brake fluid level inputs sending the IC a message to turn the brake warning indicator on when the parking brake is applied, when the brake fluid level is low or if the SJB detects an open in the brake fluid level signal or return circuits. When the ABS module detects a base brake system concern or other ABS-related concerns that affect the EBD function, the ABS module sends a message to the IC to illuminate both the ABS warning indicator and the brake warning indicator.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Brake fluid level switch
- Parking brake warning indicator switch
- SJB
- IC
PINPOINT TEST K: 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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K1 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 and observe the brake warning indicator.
- Does the brake warning indicator illuminate when commanded on?
Yes
GO to K2.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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K2 DETERMINE IF THE BRAKE WARNING INDICATOR OPERATES WITH THE PARKING BRAKE
- Apply the parking brake while monitoring the brake warning indicator.
- Does the brake warning indicator illuminate with the parking brake applied?
Yes
GO to K7.
No
GO to K3.
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K3 CHECK THE PARKING BRAKE SWITCH PID
- Enter the following diagnostic mode on the scan tool: SJB DataLogger .
- Select the SJB parking brake (PRK_BRAKE) PID. Monitor the parking brake PID while applying the parking brake.
- Does the PID agree with the parking brake position?
Yes
GO to K9.
No
GO to K4.
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K4 CHECK THE PARKING BRAKE WARNING INDICATOR SWITCH
- Ignition OFF.
- Disconnect: Parking Brake Warning Indicator Switch C2015 .
- Connect a fused jumper wire between the parking brake warning indicator switch C2015-1, circuit GD182 (BK/GY), harness side and the parking brake warning indicator switch C2015-2, circuit CMC25 (WH/VT), harness side.
- Ignition ON.
- Monitor the brake warning indicator.
- Does the brake warning indicator illuminate?
Yes
REMOVE the jumper wire. INSTALL a new parking brake warning indicator switch. REFER to Parking Brake System. TEST the system for normal operation.
No
REMOVE the jumper wire. GO to K5.
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K5 CHECK THE PARKING BRAKE WARNING INDICATOR SWITCH GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable .
- Measure the resistance between the parking brake switch C2015-1, circuit GD182 (BK/GY), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K6.
No
REPAIR circuit GD182 (BK/GY) for an open. TEST the system for normal operation.
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K6 CHECK THE PARKING BRAKE WARNING INDICATOR SWITCH SIGNAL CIRCUIT FOR AN OPEN
- Disconnect: SJB C2280c .
- Measure the resistance between the SJB C2280c-1, circuit CMC25 (WH/VT), harness side and the parking brake switch C2015-2, circuit CMC25 (WH/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K10.
No
REPAIR circuit CMC25 (WH/VT) for an open. TEST the system for normal operation.
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K7 CHECK THE BRAKE FLUID LEVEL SWITCH
NOTE: Verify that the brake fluid level is low or was low prior to either adding brake fluid or a brake system repair.
- Ignition OFF.
- Disconnect: Brake Fluid Level Switch C124 .
- Connect a fused jumper wire between the brake fluid level switch C124-1, circuit GD120 (BK/GN), harness side and the brake fluid level switch C124-2, circuit CMC19 (GY/VT), harness side.
- Ignition ON.
- Monitor the brake warning indicator.
- Does the brake warning indicator turn on?
Yes
INSTALL a new brake fluid level switch. TEST the system for normal operation.
No
REMOVE the jumper wire. GO to K8.
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K8 CHECK THE BRAKE FLUID LEVEL INPUT CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280f .
- Measure the resistance between the SJB C2280f-9, circuit CMC19 (GY/VT), harness side and the brake fluid level switch C124-2, circuit CMC19 (GY/VT), harness side; and between the SJB C2280f-22, circuit CMC19 (GY/VT), harness side and the brake fluid level switch C124-2, circuit CMC19 (GY/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to K9.
No
REPAIR circuit CMC19 (GY/VT) for an open. TEST the system for normal operation.
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K9 CHECK THE BRAKE FLUID LEVEL GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable .
- Measure the resistance between the brake fluid level switch C124-1, circuit GD120 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to K10.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
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K10 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?
Yes
INSTALL a new SJB. REFER to Body Control Systems. CLEAR the DTCs. REPEAT the self-test.
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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