What does fault code P1854 mean?
2 Answers
P1854 fault code indicates a Controller Area Network (CAN) data link issue in the Anti-lock Braking System (ABS) - hardware defect. More details about fault code P1854 are as follows: 1. Controller Area Network (CAN) is an automotive communication protocol characterized by allowing direct communication between devices on the network without requiring a host to control the communication; 2. The function of the Anti-lock Braking System (ABS) is to prevent wheel lock-up, enabling the car to steer while braking, ensuring the vehicle's braking directional stability, and preventing skidding and deviation; 3. After troubleshooting car faults, it is generally necessary to clear the fault codes. When clearing fault codes, it is essential to follow the specified method for the corresponding vehicle model; 4. Never disconnect the negative battery cable directly to clear fault codes. Otherwise, it may cause the following two issues: First, some vehicle models' control computers may lose "historical records"; Second, the engine operation data stored in RAM may be lost, leading to suboptimal performance of the car for a long time after repair, or the reappearance of previously cleared fault codes after some driving.
Fault code P1854 typically indicates an issue with the low-range switch circuit in the four-wheel drive system. Specifically, in off-road vehicles, this switch controls the engagement of 4WD low-range mode, which provides increased torque for climbing or rough terrain. The circuit malfunction may stem from switch wear, loose connectors, corroded wiring, or relay failure. This issue is commonly seen in models like the Jeep Wrangler or Toyota Tacoma. If you drive such a vehicle, you might notice rough 4WD shifting, a dashboard warning light during operation, and compromised off-road performance—though daily driving remains possible. It’s recommended to first use an OBD scanner to pinpoint the issue, then inspect the switch and related wiring to prevent minor problems from escalating. Prompt repairs can avoid more complex drivetrain issues and maintain vehicle reliability.
