What does fault code P1854 mean?

[Juliet]

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.

[McHailey]

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.

[OLydia]

As someone who frequently drives SUVs, I have encountered the P1854 trouble code issue. It's essentially a malfunction in the low-range switch circuit of the four-wheel drive system. The dashboard will display a warning light, and attempting to shift into low-range four-wheel drive while driving may not work, making it harder to climb slopes. This issue is more common in older vehicles, possibly due to moisture in the wiring or switch wear. My advice is not to panic—first check if the fuse is blown, then have someone test the switch. If left unrepaired, it could pose risks during off-road driving. Regularly avoiding flooded areas can help extend the lifespan of these components.

[LeArthur]

The P1854 trouble code indicates a malfunction in the 4WD low-range switch circuit, which can be caused by a faulty switch, short circuit in the wiring, or relay issues. This prevents the vehicle from switching to low-range 4WD mode, affecting torque output, especially on muddy or snowy roads. Long-term neglect may accelerate drivetrain wear and increase repair costs. In simple terms, it's a signal error caused by circuit interruption.