Pinpoint Test B: Without A Trailer Connected To The Vehicle And With The Ignition Key Turned To The Run Position, The TBC Modul
Auxiliary Brake System - Trailer Brake Control (TBC) Module
Pinpoint Test B: Without a Trailer Connected to the Vehicle and With the Ignition Key Turned to the RUN Position, the TBC Module Display Does Not Light Up/Prove Out
NOTE: Carry out all pinpoint tests without a trailer connected to the vehicle.
Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information. Diagrams By Number
Normal Operation
The voltage supply to the Trailer Brake Control (TBC) module must be between 9 and 16 volts for TBC module wake up, prove out and operation. If the voltage falls below or goes above these parameters, the appropriate DTC will be set. The TBC module receives fused battery voltage from Battery Junction Box (BJB) fuse 17 (30A) along circuit SBB17 (RD) and fused ignition voltage from Smart Junction Box (SJB) fuse 33 (10A) along circuit CBP33 (WH/BN). The ground path for the TBC module is along circuit GD138 (BK/WH).
- DTC B1317 (Battery Voltage High) - If the battery voltage is greater than 16 volts for 200 ms or longer, the TBC module shuts off trailer brake output and then shuts down.
- DTC B1318 (Battery Voltage Low) - If the battery voltage is less than 9 volts for 200 ms or longer, the TBC module shuts off trailer brake output and then shuts down.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Vehicle battery
- Vehicle charging system
- TBC module
PINPOINT TEST B: WITHOUT A TRAILER CONNECTED TO THE VEHICLE AND WITH THE IGNITION KEY IN THE RUN POSITION, THE TBC MODULE DISPLAY DOES NOT LIGHT UP/PROVE OUT
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
NOTE: DTC B1317, B1318 or B1676 can be set if the vehicle has been recently jump started, the battery has been recently charged or the battery has been discharged. The battery may become discharged due to excessive load(s) on the charging system from aftermarket accessories or if the battery has been left unattended with the accessories on.
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B1 RETRIEVE ALL CMDTCs IN ALL MODULES
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - All CMDTCs.
- Is DTC B1317, B1318 or B1676 present in one or more modules AND DTC P0563, P0620, P0625, P0626 or P065B present in the PCM?
Yes
REFER to Charging System for diagnosis of the battery and charging system.
No
GO to B2.
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B2 CHECK BATTERY CONDITION
- Ignition OFF.
- Refer to Battery and carry out the Battery - Condition Test. Pinpoint Tests
- Does the battery pass the condition test?
Yes
If the battery passed the condition test but required a recharge, REFER to Charging System to diagnose the charging system. CLEAR all Continuous Memory Diagnostic Trouble Codes (CMDTCs). TEST the system for normal operation.
If the battery passed the condition test and did not require a recharge, GO to B3.
No
INSTALL a new battery. CLEAR all CMDTCs. TEST the system for normal operation.
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B3 CHECK THE CHARGING SYSTEM VOLTAGE
NOTE: Do not allow the engine rpm to increase above 2,000 rpm while performing this step or the generator may self excite and result in default charging system output voltage. If engine rpm has gone above 2,000 rpm, shut the vehicle OFF and restart the engine before performing this step.
- Start the engine.
- Measure the voltage of the battery:
- For DTC B1317, turn off all accessories and run the engine at 1,500 rpm for a minimum of 2 minutes.
- For DTC B1318, turn on headlights and HVAC fan on high and run engine at 1,500 rpm for a minimum of 2 minutes.
- Is the battery voltage between 13-15.2 volts?
Yes
For DTC B1318, GO to B4.
For DTC B1317, GO to B6.
No
REFER to Charging System to diagnose the charging system. CLEAR all CMDTCs. TEST the system for normal operation.
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B4 CHECK THE VOLTAGE TO THE TBC MODULE
- Ignition OFF.
- Disconnect: TBC Module C2142.
- Ignition ON.
- Measure the voltage between ground and:
- TBC module C2142-8, circuit SBB17 (RD), harness side.
- TBC module C2142-9, circuit CBP33 (WH/BN), harness side.
- Are the voltages greater than 10 volts?
Yes
GO to B5.
No
VERIFY BJB fuse 17 (30A) is OK. If OK, REPAIR circuit SBB17 (RD).
VERIFY SJB fuse 33 (10A) is OK. If OK, REPAIR circuit CBP33 (WH/BN).
If either fuse is not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
CLEAR the DTCs. REPEAT the self-test.
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B5 CHECK THE TBC MODULE GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between TBC module C2142-3, circuit GD138 (BK/WH), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to B6.
No
REPAIR circuit GD138 (BK/WH). CLEAR the DTCs. REPEAT the self-test.
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B6 CHECK FOR CORRECT TBC MODULE OPERATION
- Check the TBC module connector for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: TBC Module C2142.
- Make sure the connector is seated correctly, then operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new TBC module. 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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