P0987: Transmission Fluid Pressure Sensor/Switch E Circuit

What does P0987 mean?

General circuit fault of transmission fluid pressure sensor or switch E. No manufacturer documents this code publicly. The only public user of switch E found, GM's 6T70/6T75 family (Saab 9-4X: switch 5 on the low/reverse and 4-5-6 clutch regulator valve), reports only P0989 and P0990 for it, both as plausibility counts. P0987 is the slot for a module that sees a generic circuit fault on a fifth pressure sensor or switch, for example an open or out-of-range signal, without separating low from high. CARB requires circuit checks on transmission inputs. Range/performance is P0988, low and high are P0989/P0990; switches A to D use P0840 to P0878. Typical effects are frozen shift adaptations and harsher shifts.

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

Symptoms

• Warning light depending on manufacturer
• Harsher or less consistent shifts
• Possible limp mode

Common causes

• High Failed pressure sensor or switch E
• Medium Open or shorted signal wire or poor connector contact
• Low Faulty input stage in the transmission control module

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