C003F — Wheel Speed Sensors Rotation Direction Correlation

C003F is stored when the ECU sees correlation on ABS / wheel speed. That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.

Common causes

The cause is almost always one of a few things. Here they are — C003F rarely comes from anything outside this list:

• Two sensors that should agree are reading differently
• One of the pair has drifted while both remain electrically fine
• Mechanical fault making the disagreement genuine
• Timing or alignment out of specification

Where to start

In the order a sensible mechanic would work — the cheap checks first, the expensive replacements only after:

1. Read both values side by side on live data — the code is about their relationship, so one alone tells you nothing
2. Identify which of the two is wrong by comparing against a third reference
3. Check the mechanical alignment or timing the pair is measuring
4. Inspect wiring on both sensors before replacing either
5. Replace whichever sensor is demonstrably the outlier

That is what holds for C003F in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.