Trailer Detection (Tow Vehicle) error codes

25 codes from 7 manufacturers, each with its meaning and the document it comes from. Open a code for the details, or search every system.

Ford (6)

• B1D08:11Left trailer direction indicator - circuit short to ground. A LAMP code, despite the 'Trailer Brake System…
• B1D08:12Left trailer direction indicator - circuit short to battery.
• B1D09:11Right trailer direction indicator - circuit short to ground. A LAMP code.
• B1D09:12Right trailer direction indicator - circuit short to battery.
• U2100:00Initial configuration not complete - TRM. Typically after an accessory brake-control kit install.
• U0137Lost communication with Trailer Brake Control Module (set in ABS).

GM (3)

• C1114Circuit 47 (trailer brake control) fault. GM's usage: short to ground gives 'Check Trailer Wiring'; short to…
• B3885-04Trailer left tail lamp circuit (U1D vehicles). Presents as trailer lighting dead or 'Trailer Disconnected…
• B3886-04Trailer right tail lamp circuit (U1D vehicles).

Jeep / Ram (1)

• B235C-64Trailer Connection - Signal Plausibility Failure. Random 'trailer disconnected' while driving.

Jeep / Ram (TTM / ITCM) (1)

• B166A-13Trailer lamp driver circuit low. Default action: EVIC displays 'trailer disconnected' - a LIGHTING fault…

Nissan / Tekonsha Prodigy P2 (5)

• n.c.No connection. Flashes for about 15 seconds at start-up, which is NORMAL. Sustained display means trailer not…
• o.gOpen ground - trailer connected but the controller lost its own battery ground.
• o.LOverload during operation.
• s.HShort seen at idle.
• P.LPower loss - lost voltage on the black wire while the pedal or manual lever was applied.

Ram / Stellantis (5)

• C10C7-00Service Trailer Brakes - ignition voltage below 9 V or above 16 V.
• C10C7-11Service Trailer Brakes - ITBM senses a short on the Electric Brake Feed circuit.
• C10C7-19Check Trailer Wiring - overcurrent to the trailer brakes. A shorted magnet, or simply too many magnets.
• C2213-00'trailer disconnected' displayed because the ITBM failed its internal self-test - NOT a wiring problem.
• C2214-00'trailer disconnected' because the ITBM is not calibrated.

Toyota (4)

• C14A6Trailer brake output circuit open - the trailer-disconnect code. INF 61 requires an open for at least 1.9…
• C14A4Trailer brake output overcurrent - trips above roughly 27.8-40 A for at least 1 second.
• C1241Power supply voltage out of range. INF 81 = ignition below 7.9 V for 5 s above 3 km/h; INF 82 = above 17.8 V…
• C13A9Brake system malfunction reported to the TBC by the skid control ECU. The cascade code.