Pinpoint Test

NOTE: Before beginning diagnostics, visually inspect the trailer tow connector mounted on the bumper for signs of corrosion or damage. Repair or install a new trailer tow connector as required.

CHECK THE TRAILER ELECTRIC BRAKE CONTROLLER FOR A SHORTED OUTPUT

Ignition ON.

Measure:

Trailer Tow Connector			Ground

Trailer Tow Connector			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
3	CAT19 (BU)		-	Ground

Is any voltage present?

Yes: GO to 2 .
No: GO to 3.

CHECK THE TBC MODULE OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE

Disconnect: TBC Module.

Measure:

Trailer Tow Connector			Ground

Trailer Tow Connector			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
3	CAT19 (BU)		-	Ground

Is any voltage present?

Yes: REPAIR the circuit.
No: INSTALL a new TBC module.

CHECK THE TBC MODULE OUTPUT

Ignition OFF.
Set the gain on the trailer electric brake controller to the maximum setting.

While applying the brake pedal, measure:

Trailer Tow Connector			Ground

Trailer Tow Connector			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
3	CAT19 (BU)		-	Ground

Is the voltage greater than 11 volts?

Yes: The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
No: GO to 4 .

CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (VEHICLE HARNESS)

Disconnect: Trailer Tow Connector.

NOTE: Make sure the gain is set to the maximum setting.

While applying the brake pedal, measure:

Trailer Tow			Ground

C4099			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
3	CAT19 (BU)		-	Ground

Is the voltage greater than 11 volts?

Yes: INSTALL a new trailer tow connector.
No: GO to 5 .

CHECK THE TBC MODULE VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Disconnect: TBC Module.

Measure:

TBC Module			Ground

C2142			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
1	CAT18 (YE/OG)		-	Ground

Is the voltage greater than 11 volts?

Yes: GO to 6 .
No: VERIFY the BJB fuse 3 (30A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the appropriate OEM WIRING DIAGRAMS to identify the cause for the circuit short.

CHECK THE TBC MODULE GROUND CIRCUIT FOR AN OPEN

Measure:

TBC Module			TBC Module

C2142			C2142
Pin	Circuit	Measurement / Action	Pin	Circuit
1	CAT18 (YE/OG)		6	GD215 (BK/GY)

Is the voltage greater than 11 volts?

Yes: GO to 7 .
No: REPAIR the circuit.

CHECK THE STOPLAMP SWITCH INPUT TO THE TBC MODULE

While applying the brake pedal, measure:

TBC Module			Ground

C2142			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
2	CBP31 (BU/OG)		-	Ground

Is the voltage greater than 11 volts?

Yes: GO to 9.
No: VERIFY the BCM fuse 31 (5A) Is OK. If OK, GO to 8 . If not OK, REFER to the appropriate OEM WIRING DIAGRAMS to identify the cause for the circuit short.

CHECK THE STOPLAMP SWITCH INPUT CIRCUIT TO THE TBC MODULE FOR AN OPEN

Disconnect: BCM C2280B.

Measure:

TBC Module			BCM

C2142			C2280B
Pin	Circuit	Measurement / Action	Pin	Circuit
2	CBP31 (BU/OG)		4	CBP31 (BU/OG)

Is the resistance less than 3 ohms?

Yes: GO to 11.
No: REPAIR the circuit.

CHECK THE TBC MODULE OUTPUT CIRCUIT FOR A SHORT TO GROUND

Measure:

TBC Module			Ground

C2142			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
3	CAT19 (BU)		-	Ground

Is the resistance greater than 10, 000 ohms?

Yes: GO to 10 .
No: REPAIR the circuit.

CHECK THE TBC MODULE OUTPUT CIRCUIT FOR AN OPEN

Connect a fused jumper wire:

TBC Module			TBC Module

C2142			C2142
Pin	Circuit	Measurement / Action	Pin	Circuit
1	CAT18 (YE/OG)		3	CAT19 (BU)

Measure:

Trailer Tow			Ground

C4099			Ground
Pin	Circuit	Measurement / Action	Pin	Circuit
3	CAT19 (BU)		-	Ground

Is the voltage greater than 11 volts?

Yes: INSTALL a new trailer electric brake controller.
No: REPAIR the circuit.

CHECK FOR CORRECT BCM OPERATION
1. Disconnect and inspect all BCM connectors.
2. Repair:
  - corrosion (install new connector or terminals - clean module pins)
  - damaged or bent pins - install new terminals/pins
  - pushed-out pins - install new pins as necessary
3. Reconnect the BCM connectors. Make sure they seat and latch correctly.
4. Operate the system and determine if the concern is still present.
Is the concern still present?
- Yes: CHECK OASIS for any applicable TSBs . If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no TSBs address this concern, INSTALL a new BCM. REFER to BODY CONTROL MODULE (BCM) - WITHOUT INTELLIGENT ACCESS (IA) , or REFER to BODY CONTROL MODULE (BCM) - WITH INTELLIGENT ACCESS (IA) .
- No: The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.