P0798: Pressure Control Solenoid C Electrical

What does P0798 mean?

Pressure control solenoids are current-controlled proportional valves, and what B and C mean depends on the design: on GM's clutch-to-clutch automatics they are the pressure valves of clutches 2 and 3, on GM's CVT B is primary pulley pressure and C line pressure, on Jatco CVTs B is the secondary pressure valve, on Saab's AF40 B and C are clutch valves SLC1/SLC2. P0798 is the electrical code for valve C. Only Saab's 9-5 (2010–11) with Aisin AF40 uses it: a deviation between commanded and feedback current of clutch valve SLC2 (normal range 0.1–1.1 A), with the circuit codes P0969–P0971 alongside, rated after two trips. The module switches all solenoids off and keeps only second gear and reverse, without adaption. GM and Ford use the circuit codes P0968–P0971 instead.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Limp mode (second gear and reverse only)
• Harsh shifts
• Transmission warning or check engine light

Common causes

• High Clutch valve SLC2 coil faulty
• Medium Wire or connector open or shorted
• Low Transmission module damaged (e.g. after a short)

Likelihood is a general estimate across vehicles; your make and model may differ.