C05F2Rear Drive Shaft Speed Sensor Circuit Intermittent
- Generic OBD-II code · Chassis
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The speed signal from the rear drive shaft drops out or jumps for short moments and then recovers, so the AWD controller sees pulse gaps or sudden speed steps that no real shaft could make. Such sensors are often two-wire Hall ICs whose supply current toggles between two levels; Allegro specifies about 7 and 14 mA for its A19420 and stresses stable output despite sudden air gap changes, so short dropouts usually point to wiring, connector or mounting rather than the IC. American Axle uses a speed sensor on the rear drive module pinion shaft to judge synchronisation before a disconnect clutch engages; Audi lists the drive shaft speed sensor G970 for quattro ultra. No maker documents C05F2 itself; permanent faults are C05F0, C05F1 or C05F3.
- What you may notice
- AWD or 4WD warning appears now and then and disappears again
- All-wheel drive briefly unavailable, often on rough roads
- Code stored as history without a current fault
- Likely causes
- LikelyLoose, corroded or water-affected connector at the sensor
- PossibleHarness chafed or broken where it flexes near the axle or drive shaft
- PossibleSensor not seated firmly, air gap varies with vibration
- RareDamaged or dirty target ring on the shaft
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.