Hi all I have a problem on my 95 wrx.
It came up with a fault 42 throttle position sensor so I bought a second hand one off a member on here and after fitting it as JGM website says,it ran ok for a few days then started coming up with a fault 31 idle switch. Now am I right in saying that these two things are on the same unit?
Anyways I swapped back to my original one and its back with fault 42.
If they are the same unit is it likely that Ive bought a faulty unit or is there something else lurking that could be causing the problem?

Thanks.

 

42 is idle control valve.
31 is throttle sensor.

I am having the same problems. I am going to buy a new idle valve.

 

No its not mate.

24 idle air control solenoid
31 throttle position sensor
42 idle switch.

 

My bad...

What is the idle switch? I am getting a 31 and a 42. Have replaced the throttle sensor and tried to set it up (can get the exact closed voltage, but then the open voltage is out??) but still running crap aswell.

 

I imagine the idle switch is a virtual switch calculated/based on the TPS voltage. i.e. TPS voltage should be greater than 4.2V at idle.

However I am 100% sure that code 42 is cured purely by adjusting the TPS.

 

Sorry to thread hijack. But while were all in the same place me and the original op might benefit from my question.

I can't seem to adjust my sensor so that the open and closed voltages are to the required spec. Closed is 4.7 but then it knocks my open voltage out.

What's going on there?

 

What is your open throttle voltage?

Aim for closed throttle voltage of 4.5V (you don't want to adjust for the edge of acceptable range as you have been doing).

Looking at logs that I made last week, with a closed throttle voltage of 4.5V, open throttle voltage is about 2V to 1.7V.

 

Musso

Have someone fully depress the accelerator and manually check on the throttle body that its fully opening it might be that your throttle cable needs adjusting as mine did.
This hasn't cured my problem just enabled me to set the tps correctly.