Chassis, generic

C0402 Rear Drive Clutch Solenoid Valve

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Open or shorted solenoid valve circuit at the rear drive unit
Valve calibration not stored after module replacement
Solenoid valve sticking because of contaminated or aged clutch fluid
Corroded connector on the rear axle module

Symptoms

  • Service Rear Axle or AWD warning displayed
  • Car drives on the front wheels only

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

clutch solenoidawd control moduleawd coupling

Related codes

C0374C0400

References: saabwisonline.com, saabwisonline.com, saabwisonline.com, saabwisonline.com.