P0989Transmission Fluid Pressure Sensor/Switch E Circuit Low
- Generic OBD-II code · Powertrain
- Can trigger limp mode
- How the car detects it
- Pressure switch E reads low, meaning no pressure, when it should show pressure. GM's 6T70/6T75 family uses E for switch 5 on the R1/4-5-6 clutch regulator valve; the normally closed switch sees pressure while both the low/reverse and the 4-5-6 clutch are released. The module counts clutch releases after which the signal stays low, checked with commanded clutch pressure at 50 kPa or less: 18 counts in GM's 2011 tables and on the Saab 9-4X, 17 in the 2016 table. It is a Type C or Special No Trip code without MIL, and the adaptations of both clutches are frozen. Sonnax lists P0989 among typical switch failures in this valve body module. P0990 is the stuck-high counterpart; switches A to D use P0840 to P0878.
- What you may notice
- No warning light, code stored only
- Shifts into 4th to 6th or reverse gradually less smooth
- Occasional limp mode if the fault persists
- Likely causes
- LikelyDamaged or delaminated film in switch 5 of the valve body module
- PossibleDebris keeping pressure away from the switch
- PossibleR1/4-5-6 clutch regulator valve sticking
- RareLow fluid level
- 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.