Pinpoint Test K: The Stoplamp(s) Are On Continuously
Stoplamps
Pinpoint Tests
Pinpoint Test K: The Stoplamp(s) Are On Continuously
Refer to Wiring Diagram Set 90, Turn Signal/Stop/Hazard Lamps for schematic and connector information. Diagrams By Number
Normal Operation
When the brake pedal is applied, the stoplamp switch routes voltage to the Smart Junction Box (SJB), the PCM and the stoplamp relay (coil side).
The SJB provides voltage to the rear lamps when it receives input from the stoplamp switch indicating that the brake pedal is applied.
When the stoplamp relay is energized (brake pedal applied), voltage is routed to the high mounted stoplamp and the Trailer Brake Control (TBC) module (factory equipment) or the trailer electric brake controller (aftermarket).
- DTC B1485 (Brake Pedal Input Short to Battery) - an on-demand DTC that sets when the SJB detects a short to voltage from the stoplamp switch input circuit.
- DTC B2045 (Left Rear Stop Lamp Circuit Open) - an on-demand DTC that sets when the SJB detects a short to voltage from the LH rear stop/turn lamp voltage supply circuit.
- DTC B2047 (Right Rear Stop Lamp Circuit Open) - an on-demand DTC that sets when the SJB detects a short to voltage from the RH rear stop/turn lamp voltage supply circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Stoplamp relay
- Stoplamp switch
- TBC module (factory equipment)
- Trailer electric brake controller (aftermarket equipment)
- PCM
- SJB
PINPOINT TEST K: THE STOPLAMP(S) ARE ON CONTINUOUSLY
NOTICE: It is important to install relays in their correct position in the Battery Junction Box (BJB). Installing a relay incorrectly can cause wiring shorts or damage to modules. While carrying out diagnostics on BJB relays, have only one BJB relay removed at a time. Failure to follow these instructions can result in damage to the vehicle circuitry or to controlling modules.
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K1 USE THE RECORDED DTCs FROM THE SJB SELF-TEST
- Check the recorded results from the SJB on-demand self-test.
- Is DTC B1485, B2045 or B2047 present?
Yes
For DTC B2045 or DTC B2047, GO to K2.
For DTC B1485, GO to K3.
No
GO to K6.
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K2 CHECK THE STOPLAMPS VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280d.
- Do the rear stoplamps continue to illuminate?
Yes
If the LH rear lamp continues to illuminate, REPAIR circuit CLS18 (GY/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
If the RH rear lamp continues to illuminate, REPAIR circuit CLS19 (VT/OG) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to K10.
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K3 CHECK THE STOPLAMP SWITCH
- Disconnect: Stoplamp Switch C278.
- Do the stoplamps continue to illuminate?
Yes
GO to K4.
No
INSTALL a new stoplamp switch. REFER to Stoplamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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K4 CHECK THE PCM
- Disconnect: PCM C175b (Gasoline Engine) or C1232a (Diesel Engine).
- Do the stoplamps continue to illuminate?
Yes
GO to K5.
No
GO to K8.
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K5 CHECK THE STOPLAMP RELAY (COIL SIDE) VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280b.
- Does the high mounted stoplamp continue to illuminate?
Yes
REPAIR circuit CCB08 (VT/WH) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to K10.
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K6 CHECK THE STOPLAMP RELAY
- Disconnect: Stoplamp Relay.
- Does the high mounted stoplamp continue to illuminate?
Yes
If the vehicle is equipped with a factory TBC module or an aftermarket trailer electric brake controller, GO to K7.
If the vehicle is not equipped with a factory TBC module or an aftermarket trailer electric brake controller, REPAIR circuit CLS43 (YE/GN) for a short to voltage. TEST the system for normal operation.
No
INSTALL a new stoplamp relay. TEST the system for normal operation.
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K7 CHECK THE TBC INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: TBC Module (Factory Equipment) or Trailer Electric Brake Controller (Aftermarket Equipment) C2142.
- Does the high mounted stoplamp continue to illuminate?
Yes
REPAIR circuit CLS43 (YE/GN) for a short to voltage. TEST the system for normal operation.
No
For a factory-equipped TBC module, GO to K9.
For an aftermarket-equipped trailer electric brake controller, INSTALL a new trailer electric brake controller. TEST the system for normal operation.
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K8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM 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 PCM. REFER to Computers and Control Systems. 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.
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K9 CHECK FOR CORRECT TBC MODULE OPERATION
- Disconnect the TBC module connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the TBC 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 TBC module. REFER to Trailer Brake 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.
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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 verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new SJB. REFER to Body Control Systems. 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.
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