C05F2 code meaning
Rear Drive Shaft Speed Sensor Circuit Intermittent
What C05F2 means
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.
C05F2 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of C05F2
- 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
Common causes of C05F2
- Most 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
- Less likelyDamaged or dirty target ring on the shaft
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Rear drive shaft speed sensorAwd control module
What each part of C05F2 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| F2 | The exact fault in that area. |
What to do next
- Note C05F2 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C05F2
What does C05F2 mean?
C05F2 means "Rear Drive Shaft Speed Sensor Circuit Intermittent". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with C05F2?
Drive gently and only to a workshop. With C05F2 the car can go into limp mode (reduced power) to protect itself.
Will C05F2 fail an emissions test?
C05F2 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C05F2 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C05F2 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.