Powertrain, generic · Transmission

P0966 Pressure Control Solenoid B Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Pressure control solenoid B circuit low, meaning a short to ground in the driver circuit. On GM's six-speeds and the Saab 9-4X 6T70, B is clutch pressure solenoid 2 for the 3-5-reverse clutch; a short lasting 0.3 s (GM 2018 table) or 1 s (Saab) sets a Type A code with a fixed limp mode: reverse and 5th gear, maximum line pressure, converter clutch off. GM's 8-, 9- and 10-speeds use B for a clutch solenoid and treat less than 0.5 ohm as a short; Allison 1000 uses it for pressure control solenoid 2 with ground-short detection in 125 ms. Ford does not use the B codes. Siblings are P0964 open, P0967 high and P0965 performance; solenoids A and C follow the same scheme.

Likely causes

Chafed control wire touching ground
Internally shorted solenoid in the valve body assembly
Fluid or moisture in the connector
Faulty output stage in the control module

Symptoms

  • MIL on immediately
  • Limp mode with reverse and one forward gear
  • No torque converter lock-up, higher fuel consumption

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–1,800
Time1–5 h

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

Parts involved

pressure control solenoid bwiring harnesstcm

Related codes

P0964P0965P0967P0962P0970P0777

References: saabwisonline.com, gsi.ext.gm.com, gsi.ext.gm.com.