C00974WD/AWD Rear Differential Unit Actuator B
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- Covers actuator B of the rear differential unit, the second actuator used on rear drive modules that control two functions, for example torque transfer and a limited-slip or locking element, or that use two coils for redundancy. The controller drives this actuator to engage or modulate the rear coupling; this code is set when the actuator B circuit is open, shorted, out of range or the actuator does not respond. AWD coupling patents describe drive axles with more than one hydraulically or electromagnetically controlled coupling, one for front-to-rear torque transfer and one for side-to-side limited slip. A fault can lock the affected function or default it to open, reducing traction or torque vectoring, and sets the AWD/4WD warning lamp; braking and ABS are unaffected. It is the counterpart to actuator A (C0095).
- What you may notice
- AWD/4WD warning lamp on
- Limited-slip or lock function lost
- Reduced traction or torque vectoring
- Likely causes
- LikelyRear coupling actuator B failed
- PossibleOpen or shorted actuator circuit
- RareBinding or worn rear coupling
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €250 – €2,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.