Chassis, generic

C0173 Right Rear ABS Outlet Solenoid Circuit Malfunction

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

No accessible J2012 list, maker index or NHTSA bulletin contains C0173, so the code cannot be tied to any vehicle; Saab, for instance, reports a fault in either valve of the right rear wheel as C2485. By its title it covers the release valve of the right rear brake. In the Saab hydraulic unit this valve is closed at rest and opens, together with the return pump, only when that wheel nears lock-up, letting fluid out of the caliper into a small accumulator. Saab energises every valve for 20 ms in a self-test at each key-on and switches ABS, traction and stability control off when one fails. An outlet coil that cannot open leaves the rear wheel prone to locking during ABS braking; a leaking one lets the caliper lose pressure.

Likely causes

Open or shorted coil of the right rear outlet valve
Corroded or loose contact between valve block and control module
Faulty valve driver stage inside the control module

Symptoms

  • ABS and brake warning lamps on, ABS/TCS/ESC switched off
  • Right rear wheel may lock under hard braking

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time0.5–3 h

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

Parts involved

abs hydraulic unitabs control modulesolenoid valve

Related codes

C0168C0209C0163

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