P0990Transmission Fluid Pressure Sensor/Switch E Circuit High
- Generic OBD-II code · Powertrain
- How the car detects it
- Pressure switch E reads high, meaning pressure, when it should be vented. GM's 6T70/6T75 family uses E for switch 5 on the R1/4-5-6 clutch regulator valve; applying the low/reverse or 4-5-6 clutch moves that valve and should exhaust the switch. If the signal stays high after such an apply, with commanded clutch pressure at 700 kPa or more, the module counts it: 15 counts on the Saab 9-4X, 30 in GM's 2016 table. It is a Type C or Special No Trip code, so no MIL, and the adaptations of both clutches are frozen. According to Saab, normal debris in the fluid can set it intermittently without noticeable symptoms. A short to voltage on the signal wire has the same effect. P0989 is the stuck-low case.
- What you may notice
- No warning light, code stored only
- Intermittent occurrence without noticeable symptoms
- Shift quality declines over time
- Likely causes
- LikelySwitch 5 stuck open by a damaged film or debris
- PossibleR1/4-5-6 regulator valve not moving, switch stays pressurised
- RareSignal circuit shorted to voltage or open inside the module
- Repair
- Hard · Usually a job for a workshop.Typical cost: €300 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.