Engine check lights just come on on my 93 wrx, it seems to be running fine except the speedo stopped working at the same time, unrelated??? Is there anyway of finding whats causing it to come on or does it need a diags machine? Also should I still be driving it????

 

sounds like the speedo drive just failed, have a look at the speed ouput on the gearbox, you should have a convertor that sits between the gearbox and speedo cable, this may have come apart or broken, its near the turbo on the gearbox. The ECU needs the speed signal to work, so will now be in limp home mode.

 

Ah thanks very much I'll go take a look

 

You will prob find that you have a rev limit of around 4500 with the CEL on, chances are your speedo cable has snapped.
Check that your speedo cable is not touching your Downpipe (favourite on early WRX's). The ECU is linked to the back of the speedo on your instruments, when the ecu is not receiving a signal from the speedo (ie. broken cable) the CEL is illuminated and drops the rev limit.
If you look under your dash by the steering column you will see two black spade connectors (male n female) and two green connectors. With the Ignition off connect the two black connectors together and switch the ignition on. You will notice that the Check engine light (CEL) is flashing if the correct black connectors are joined.
The check engine light will flash and give you the diagnostic code. 1sec flashes = 10's and .5sec flashes = single numbers.

For example...

Black connectors together..
Ign on...

Two long flashes followed by 3 short flashes is 23..

Rob
Post up the CEL number and i'll let you know what it is...


It may sound difficult if you havent done it before but it is really easy to check for error codes and is valuble to learn.

 

You will prob find it is code 33.

Rob

just to add, you wont do any damage by driving the car ATM if it is the speedo sensor activating the CEL. BUT, just so you know.. It is an offence to drive without a speedo... Wouldnt worry me but be aware.

 

Thanks again, excellent info sounds like it isn't that serious after all. Did notice it splutter and and kangeroo around what must have been around 4500 rpm. Thought it had over-boosted or somthing!