What is the reason for the ABS communication failure in Ford Transit?
2 Answers
Ford Transit ABS communication failure may be due to no current passing through the ABS pump. Check if there is a fault in the circuit. How ABS works: During braking, ABS quickly determines the wheel lock-up state based on the speed signals from each wheel speed sensor, closes the normally open input solenoid valve on the wheel that is starting to lock up, and keeps the braking force unchanged. If the wheel continues to lock up, the normally closed output solenoid valve is opened, and the braking pressure on that wheel rapidly decreases due to the direct connection to the brake fluid reservoir, preventing the wheel from completely locking up due to excessive braking force. This keeps the braking state at the optimal point (slip ratio S of 20%), achieving the best braking effect and the highest driving safety. Classification of ABS: ABS is mainly classified based on channels. In ABS, the brake pipelines that can independently adjust the braking pressure are called control channels. ABS control channels are divided into four-channel, three-channel, two-channel, and one-channel types. One-channel ABS: Also called single-channel ABS, it has a brake pressure regulator installed in the rear wheel brake master pipe and a wheel speed sensor installed on the rear axle differential (sometimes one on each rear wheel). Two-channel ABS: This type of ABS is difficult to balance in terms of directional stability, steering control, and braking efficiency, and is rarely used today. Three-channel ABS: It independently controls the two front wheels, while the two rear wheels are controlled together based on the low-select principle (i.e., both wheels are controlled by one channel to ensure the wheel with less adhesion does not lock up), also known as hybrid control. Four-channel ABS: It has four wheel speed sensors, with a brake pressure regulator installed in the pipelines leading to the four wheel brake cylinders for independent control, forming a four-channel control system.
I've been driving a Ford Transit for over a decade, and ABS communication failures are a common occurrence, mostly due to issues with those wheel speed sensors. When the sensors get dirty or damaged, they can't accurately measure the speed, causing the ABS module to lose signal and the warning light to come on. Wiring aging is also particularly common, with connection points corroded or chewed by rodents, preventing data transmission entirely. Control module failures are even more frustrating, whether it's burnt internal ECU components or software bugs causing communication breakdowns. Once, my ABS failed completely, and after inspection, it turned out to be unstable battery voltage interfering with the signals. This issue relates directly to braking safety—don't delay if you notice it. Head to a professional shop immediately to check the fault codes and conduct a thorough inspection before hitting the road with peace of mind.
