C0402Rear Drive Clutch Solenoid Valve
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- Publicly available J2012 tables skip C0402, yet GM assigns it in its rear differential clutch control module: the 2010–11 Saab 9-5 and the 2011 9-4X call it Transfer Case Solenoid Valve and describe the rear drive clutch solenoid, which the module drives by PWM to set the clutch pressure and so the torque sent rearward; the 2008–12 Saab 9-3 XWD calls it Differential Clutch Solenoid Valve. No maker documents it as a traction control lamp circuit. Subcode 02 is a short with coil resistance below 2 Ω, 04 an open with current off target by over 200 mA for 100 ms, 42/43/4B missing or bad calibration, 61 a valve that does not engage. AWD is switched off and Service Rear Axle appears; valve and module are replaced as a matched pair.
- What you may notice
- Service Rear Axle or AWD warning displayed
- Car drives on the front wheels only
- Likely causes
- LikelyOpen or shorted solenoid valve circuit at the rear drive unit
- PossibleValve calibration not stored after module replacement
- PossibleSolenoid valve sticking because of contaminated or aged clutch fluid
- RareCorroded connector on the rear axle module
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.