My MY93 WRX has recently had the CHECK ENGINE light come on for short periods of time. Sometimes the light will come on from start-up, occasionally the light will go on and off during a long (motorway) drive, and other times the light doesn't come on at all.

I checked the ECU code, and it came up with two faults. I have reset the ECU, and the same two faults have re-appeared (after about a week).

The two faults are; 21, (water temp sensor) and 45 (pressure sensor). I can't understand why these two faults would appear at the same time? Are they inter-connected in any way?

Can anyone shed any light on the best course of action I should take? Any comments will be appreciated!!

 

Back to the top, just in case anyone has missed this post, and can provide some help.

I can add that the light has gone on and off while driving at constant speed along the motorway, but sometimes comes on from the moment the key is turned.

Crucially, twice the car has completely cut the fuel as boost was coming on (over boost?), and very shortly after the CHECK ENGINE light has come on.
I guess I may be looking at changing the pressure sensor??