فقدان الاتصال بوحدة ABS

The engine or transmission module unable to reach the anti-lock braking module. The braking module is the source of wheel speed for the whole vehicle, which is why its silence is felt far outside the brakes — traction control, stability control, cruise control, the speedometer and the transmission's shift strategy all depend on speeds it publishes.

So the codes appear in modules that have nothing to do with braking. An engine module storing a rough road or misfire-enable fault is often reporting that it has lost the wheel speed data it needs to distinguish a genuine misfire from a rough surface. A cluster of unrelated codes with one lost-communication code among them usually means the communication is the fault and the rest are consequences.

The braking module's supply is the first thing to check, since it carries heavy feeds and its own fuses, and a module without power reports as absent from the network. Then the bus wiring — measuring resistance across the pair with the ignition off is quick and tells you whether the network itself is intact. A module that is genuinely dead and one that cannot be reached look identical from every other module, and only those two checks separate them.