Pinpoint Test Q: One Or More Stoplamps Are Inoperative
Stoplamps
Pinpoint Test Q: One Or More Stoplamps Are Inoperative
Refer to Wiring Diagram Set 90, Turn Signal/Stop/Hazard Lamps for schematic and connector information Electrical Diagrams.
Normal Operation
When the brake pedal is applied, the stoplamp switch routes voltage to the Body Control Module (BCM), indicating the brake pedal is applied.
For Edge, when the BCM (Body Control Module) detects the brake pedal is applied, it provides voltage to the high mounted stoplamp and the stoplamp relay coil. When the stoplamp relay energizes, voltage is provided to the LH and RH stoplamps.
For MKX, the BCM (Body Control Module) provides voltage to all of the stoplamps (on independent circuits) when it detects the brake pedal is applied.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Stoplamp relay (Edge)
- Bulb socket (Edge)
- Rear lamp assembly (MKX)
- High mounted stoplamp
- BCM (Body Control Module)
PINPOINT TEST Q : ONE OR MORE STOPLAMPS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
Q1 DETERMINE THE INOPERATIVE STOPLAMP
- Ignition OFF.
- Apply the brake pedal and observe the stoplamps.
Are all the stoplamps inoperative?
Yes
GO to Pinpoint Test P Pinpoint Test P: All The Stoplamps Are Inoperative.
No
For the high mounted stoplamp, GO to Q2.
For Edge, if an individual rear stoplamp is inoperative, GO to Q7.
For Edge, if both rear stoplamps are inoperative, GO to Q9. TEST the system for normal operation.
For MKX, if an individual rear stoplamp is inoperative, GO to Q13.
Q2 CHECK FOR VOLTAGE TO THE HIGH MOUNTED STOPLAMP
- Disconnect: High Mounted Stoplamp C904.
- While applying the brake pedal, measure the voltage between the high mounted stoplamp C904-1, circuit CLS52 (BN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to Q3.
No
For Edge, REPAIR circuit CLS52 (BN) for an open. TEST the system for normal operation.
For MKX, VERIFY the BCM (Body Control Module) fuse 15 (15A) is OK. If OK, GO to Q4. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.
If no DTCs are present, TEST the system for normal operation.
If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present). TEST the system for normal operation.
If DTC U3000:49 is present, INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
Q3 CHECK THE HIGH MOUNTED STOPLAMP GROUND CIRCUIT FOR AN OPEN
- While applying the brake pedal, measure the voltage between the high mounted stoplamp C904-1, circuit CLS52 (BN), harness side and the high mounted stoplamp C904-2, circuit GD149 (BK/GY), harness side.
Is the voltage greater than 10 volts?
Yes
INSTALL a new high mounted stoplamp. TEST the system for normal operation.
No
REPAIR circuit GD149 (BK/GY) for an open. TEST the system for normal operation.
Q4 CARRY OUT THE BCM (Body Control Module) ON-DEMAND SELF-TEST AND RECHECK FOR VOLTAGE TO THE HIGH MOUNTED STOPLAMP
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) Self-Test.
- Clear the DTCs and repeat the BCM (Body Control Module) on-demand self-test.
- While applying the brake pedal, measure the voltage between the high mounted stoplamp C904-1, circuit CLS52 (BN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
INSTALL a new high mounted stoplamp. TEST the system for normal operation.
No
GO to Q5.
Q5 CHECK THE HIGH MOUNTED STOPLAMP OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280D.
- Measure the resistance between the high mounted stoplamp C904-1, circuit CLS52 (BN), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to Q6.
No
REPAIR circuit CLS52 (BN) for a short to ground. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present). TEST the system for normal operation.
If DTC U3000:49 is present, INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
Q6 CHECK THE HIGH MOUNTED STOPLAMP OUTPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the high mounted stoplamp C904-1, circuit CLS52 (BN), harness side and the BCM (Body Control Module) C2280D-14, circuit CLS52 (BN), harness side.
Is the resistance less than 5 ohms?
Yes
GO to Q20.
No
REPAIR circuit CLS52 (BN) for an open. TEST the system for normal operation.
Q7 CHECK FOR VOLTAGE TO THE REAR LAMP (EDGE)
- Disconnect: Inoperative Rear Lamp.
- While applying the brake pedal, measure the voltage between the LH rear lamp C414-6, circuit CLS43 (YE/GN), harness side and the ground; or between the RH rear lamp C417-6, circuit CLS43 (YE/GN), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to Q8.
No
REPAIR circuit CLS43 (YE/GN) for an open. TEST the system for normal operation.
Q8 CHECK THE REAR LAMP ASSEMBLY GROUND CIRCUIT FOR AN OPEN (EDGE)
- While applying the brake pedal, measure the voltage between the LH rear lamp C414-6, circuit CLS43 (YE/GN), harness side and the LH rear lamp C414-1, circuit GD149 (BK/GY), harness side; or between the RH rear lamp C417-6, circuit CLS43 (YE/GN), harness side and the RH rear lamp C417-1, circuit GD151 (BK/GN), harness side.
Is the voltage greater than 10 volts?
Yes
REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.
No
REPAIR circuit GD149 (BK/GY) (LH stoplamp) or circuit GD151 (BK/GN) (RH stoplamp) for an open. TEST the system for normal operation.
Q9 CHECK THE STOPLAMP RELAY
- Disconnect: Stoplamp Relay.
- Substitute a known good relay.
- Apply the brake pedal and observe the stoplamps.
Do the LH and RH stoplamps illuminate?
Yes
REMOVE the known good relay. INSTALL a new stoplamp relay. TEST the system for normal operation.
No
REMOVE the known good relay. VERIFY the BJB (Battery Junction Box) fuse 60 (15A) is OK. If OK, GO to Q10. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.
Q10 CHECK FOR VOLTAGE TO THE STOPLAMP RELAY
- Measure the voltage between the stoplamp relay pin 3, circuit SBB60 (GY/RD), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to Q11.
No
REPAIR circuit SBB60 (GY/RD) for an open. TEST the system for normal operation.
Q11 CHECK FOR VOLTAGE TO THE STOPLAMP RELAY COIL
- While applying the brake pedal, measure the voltage between the stoplamp relay pin 2, circuit CLS52 (BN), BJB (Battery Junction Box) face side and ground.
Is the voltage greater than 10 volts?
Yes
GO to Q12.
No
REPAIR circuit CLS52 (BN) for an open. TEST the system for normal operation.
Q12 CHECK THE STOPLAMP RELAY COIL GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between the stoplamp relay pin 3, circuit SBB60 (GY/RD), BJB (Battery Junction Box) face side and the stoplamp relay pin 3, circuit GD120 (BK/GN), BJB (Battery Junction Box) face side.
Is the voltage greater than 10 volts?
Yes
REPAIR circuit CLS43 (YE/GN) for an open. TEST the system for normal operation.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
Q13 CHECK FOR VOLTAGE TO THE REAR LAMP ASSEMBLY (MKX)
- Disconnect: Inoperative Rear Lamp.
- While applying the brake pedal, measure the voltage between the LH rear lamp C414-3, circuit CLS18 (GY/BN), harness side and the ground; or between the RH rear lamp C417-3, circuit CLS19 (VT/OG), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to Q14.
No
VERIFY the BCM (Body Control Module) fuse 14 (15A) (LH stoplamp) or fuse 13 (15A) (RH stoplamp) is OK. If OK, GO to Q16. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.
If no DTCs are present, TEST the system for normal operation.
If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present). TEST the system for normal operation.
If DTC U3000:49 is present, INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
Q14 CHECK THE BULB REAR LAMP ASSEMBLY GROUND CIRCUIT FOR AN OPEN (MKX)
- While applying the brake pedal, measure the voltage between the LH rear lamp C414-3, circuit CLS18 (GY/BN), harness side and the LH rear lamp C414-1, circuit GD149 (BK/GY), harness side; or between the RH rear lamp C417-3, circuit CLS19 (VT/OG), harness side and the RH rear lamp C417-1, circuit GD151 (BK/GN), harness side.
Is the voltage greater than 10 volts?
Yes
GO to Q15.
No
REPAIR circuit GD149 (BK/GY) (LH stoplamp) or circuit GD151 (BK/GN) (RH stoplamp) for an open. TEST the system for normal operation.
Q15 CHECK THE REAR LAMP JUMPER HARNESS FOR AN OPEN CIRCUIT
- Inspect the rear lamp jumper harness for an open circuit and shorts.
Is the rear lamp jumper harness OK?
Yes
INSTALL a new rear lamp assembly. REFER to Rear Lamp Assembly . TEST the system for normal operation.
No
REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.
Q16 CARRY OUT THE BCM (Body Control Module) ON-DEMAND SELF-TEST AND RECHECK FOR VOLTAGE TO THE REAR STOPLAMP
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) Self-Test.
- Clear the DTCs and repeat the BCM (Body Control Module) on-demand self-test.
- While applying the brake pedal, measure the voltage between the LH rear lamp C414-3, circuit CLS18 (GY/BN), harness side and the ground; or between the RH rear lamp C417-3, circuit CLS19 (VT/OG), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to Q17.
No
GO to Q18.
Q17 CHECK THE REAR LAMP JUMPER HARNESS FOR A SHORTED CIRCUIT
- Inspect the rear lamp jumper harness for a shorted circuit.
Is the rear lamp jumper harness OK?
Yes
INSTALL a new rear lamp assembly. REFER to Rear Lamp Assembly . TEST the system for normal operation.
No
REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.
Q18 CHECK THE REAR STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO GROUND
NOTE: It is important to disconnect the corresponding trailer tow stop/turn relay for correct test results.
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280D.
- Disconnect: Corresponding Trailer Tow Stop/Turn Relay.
- Measure the resistance between the BCM (Body Control Module) C2280D-12 (LH stoplamp), circuit CLS18 (GY/BN), harness side and ground; or between the BCM (Body Control Module) C2280D-15 (RH stoplamp), circuit CLS19 (VT/OG), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to Q19.
No
REPAIR circuit CLS18 (GY/BN) (LH stoplamp) or circuit CLS19 (VT/OG) (RH stoplamp) for a short to ground. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present). TEST the system for normal operation.
If DTC U3000:49 is present, INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
Q19 CHECK THE REAR STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Measure the resistance between the LH rear lamp C414-3, circuit CLS18 (GY/BN), harness side and the BCM (Body Control Module) C2280D-12, circuit CLS18 (GY/BN), harness side; or between the RH rear lamp C417-3, circuit CLS19 (VT/OG), harness side and the BCM (Body Control Module) C2280D-15, circuit CLS19 (VT/OG), harness side.
Is the resistance less than 5 ohms?
Yes
GO to Q20.
No
REPAIR circuit CLS18 (GY/BN) (LH stoplamp) or circuit CLS19 (VT/OG) (RH stoplamp) for an open. TEST the system for normal operation.
Q20 CHECK FOR CORRECT BCM (Body Control Module) OPERATION
- Disconnect all the BCM (Body Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM (Body Control Module) 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 BCM (Body Control 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.