Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2025 Toyota Land Cruiser BaseFACTORY OEM SERVICE PROCEDURE
Trailer Brake Control System
TRAILER BRAKE CONTROL SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| DTC Code | Description |
|---|---|
| C1020-16 | IGR Circuit Circuit Voltage Below Threshold |
| C1020-17 | IGR Circuit Circuit Voltage Above Threshold |
| C105F-62 | IGR Voltage / Actuator Supply Voltage Signal Compare Failure |
| C1150-12 | Trailer Brake Manual Slider Position Sensor Circuit Circuit Short to Battery |
| C1150-14 | Trailer Brake Manual Slider Position Sensor Circuit Circuit Short to Ground or Open |
| C1150-28 | Trailer Brake Manual Slider Position Sensor Circuit Signal Bias Level Out of Range / Zero Adjustment Failure |
| C1150-62 | Trailer Brake Manual Slider Position Sensor Circuit Signal Compare Failure |
| C1154-9E | Trailer Brake Gain (+) Switch Stuck On |
| C1155-9E | Trailer Brake Gain (-) Switch Stuck On |
| C1156-04 | MCU System Internal Failure |
| C1157-13 | Trailer Detection Circuit Circuit Open |
| C1158-72 | Power Relay Actuator Stuck Open |
| C1158-73 | Power Relay Actuator Stuck Closed |
| C115A-11 | Output Circuit Short to GND Circuit Short to Ground |
| C115A-15 | Output Circuit Short to Battery Circuit Short to Battery or Open |
| C115A-49 | Pre-Driver Internal Electronic Failure |
| C115E-00 | Functional Safety Failure (Predetermined Maximum Output Exceeded) |
| C115E-19 | Output Circuit Over Current Circuit Current Above Threshold |
| C115E-94 | Functional Safety Failure (Unintended Braking) Unexpected Operation |
| U0077-88 | Control Module Communication Bus "E" Off Bus Off |
| U0078-88 | Control Module Communication Bus "F" Off Bus Off |
| U0129-87 | Lost Communication with Brake System Control Module "A" Missing Message |
| U0155-87 | Lost Communication with Instrument Panel Cluster (IPC) Control Module Missing Message |
| U1170-87 | Lost Communication with Brake System Control Module (ch2) Missing Message |
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.