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TBC fault?

Kep4

Jäger
Hey Guys,

I need your expertise on this one.

I hooked up my Weekend Warrior 2 hours ago and the factory trailer brake controller would not recognize the connection. The gain scale showed green, the little trailer symbol began green, then turned to red for a few seconds, then the screen went blank. The manual says the truck is not sensing an electrical connection. I unhooked the trailer and the TBC did exactly the same thing. So, it seems the truck TBC is not recognizing the trailer connection.

I checked the 15 amp TBC fuse and it's good. I sprayed the trailer harness connection and the truck connection points with electrical cleaner, even though they looked fine. The plug seems to connect as always, a shove and it locks in.

I had the trailer out Thanksgiving and all was good, no work done on truck or trailer since then.

What should I look for on the truck?
 

blacksnapon

Moderator
Staff member
Hey Guys,

I need your expertise on this one.

I hooked up my Weekend Warrior 2 hours ago and the factory trailer brake controller would not recognize the connection. The gain scale showed green, the little trailer symbol began green, then turned to red for a few seconds, then the screen went blank. The manual says the truck is not sensing an electrical connection. I unhooked the trailer and the TBC did exactly the same thing. So, it seems the truck TBC is not recognizing the trailer connection.

I checked the 15 amp TBC fuse and it's good. I sprayed the trailer harness connection and the truck connection points with electrical cleaner, even though they looked fine. The plug seems to connect as always, a shove and it locks in.

I had the trailer out Thanksgiving and all was good, no work done on truck or trailer since then.

What should I look for on the truck?
Lemme look Russ. Be back shortly.
 

blacksnapon

Moderator
Staff member
It may possibly store DTCs. If not.........PINPOINT TEST H: THE INSTRUMENT CLUSTER DISPLAYS "TBC FAULT"
Test Step Result / Action to Take
H1 CHECK FOR THE PRESENCE OF A TRAILER BRAKE CONTROL (TBC) MODULE AND BRAKE PRESSURE TRANSDUCER
Verify that the vehicle is equipped with a TBC module in the instrument panel and a brake pressure transducer on the master cylinder.
Is the vehicle equipped with a TBC module and a brake pressure transducer?
Yes
GO to H2.

No
If the vehicle has a brake pressure transducer but not a TBC module, INSTALL a TBC module. CLEAR the DTCs. REPEAT the self-test.

If the vehicle has a TBC module but does not have a brake pressure transducer, GO to H4 .

If the vehicle has neither a TBC module nor a brake pressure transducer, GO to H3 .
H2 CHECK TBC MODULE COMMUNICATIONS
Using the scan tool, access the TBC module.
Does the scan tool communicate with the TBC module?
Yes
VERIFY that the instrument cluster is configured correctly, RECONFIGURE as necessary. REFER to Programmable Parameters in this section.

No
Go To Pinpoint Test a.
H3 CHECK THE VEHICLE BUILD INFORMATION
Verify that the vehicle is supposed to be equipped with a TBC module.
Is the vehicle supposed to be equipped with a TBC module?
Yes
INSTALL a trailer brake retrofit kit. CLEAR the DTCs. REPEAT the self-test.

No
VERIFY that the instrument cluster is configured correctly, RECONFIGURE as necessary. REFER to Programmable Parameters in this section.
H4 CHECK THE VEHICLE BUILD INFORMATION
Verify that the vehicle is supposed to be equipped with a TBC module.
Is the vehicle supposed to be equipped with a TBC module?
Yes
INSTALL a brake pressure transducer. Make sure to LUBRICATE the O-ring seal with clean, specified brake fluid before installation. RECONFIGURE the instrument cluster for trailer brakes, REFER to Programmable Parameters in this section. CLEAR the DTCs. REPEAT the self-test.

No
REMOVE the TBC module and install the storage bin.
 

blacksnapon

Moderator
Staff member
pinpoint test A

PINPOINT TEST A: NO COMMUNICATION WITH THE TRAILER BRAKE CONTROL (TBC) MODULE
NOTICE: Use the flex probe kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

Test Step Result / Action to Take
A1 CHECK THE MISSING CONTROLLER AREA NETWORK (CAN) SOURCE IDENTIFIER PID
Ignition ON.
Enter the following diagnostic mode on the scan tool: Missing CAN Source Identifier PID.
Does the PID indicate a missing module?
Yes
For missing powertrain control module (PCM), REFER to Section 303-14A (gasoline engine) or Section 303-14B (diesel engine).

For missing anti-lock brake system (ABS) control module, REFER to Section 206-09.

For missing instrument cluster, REFER to Section 413-01.

No
GO to A2.
A2 CHECK THE VOLTAGE TO THE TBC MODULE
Ignition OFF.
Disconnect: TBC Module C2142A.
Disconnect: TBC Module C2142B.
Ignition ON.
Measure the voltage between TBC module, harness side and ground as follows:
TBC module C2142A-1, circuit 50 (RD), harness side.
TBC module C2142B-3, circuit 298 (VT/OG), harness side.


Are the voltages greater than 10 volts?
Yes
GO to A3.

No
VERIFY CJB fuse 101 (30A) is OK. If OK, REPAIR circuit 50 (RD) for an open.

VERIFY CJB fuse 28 (10A) is OK. If OK, REPAIR circuit 298 (VT/OG) for an open.

CLEAR the DTCs. REPEAT the self-test.
A3 CHECK GROUND CIRCUIT 206 (WH) FOR AN OPEN
Ignition OFF.
Measure the resistance between TBC module C2124A-4, circuit 206 (WH), harness side and ground.

Is the resistance less than 5 ohms?
Yes
REFER to Section 418-00 to continue diagnosis of the communication network.

No
REPAIR circuit 206 (WH) for an open. CLEAR the DTCs. REPEAT the self-test.
 

Kep4

Jäger
Thanks Vince! I'll check for codes and report back....
 

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