Cannot read codes but TPS is ok!
 

I cannot read the diag codes on my e30 325is 87.

I tested the tps at it's connector, it works as it should with the pedal idle, slightly pressed and WOT (continuity 1st terminal & GND, none, continuity 3nd terminal and GND).

I also tested it at the DME connector (per Bentley) and the TPS terminals also work as they should.

Why can't I read the codes? I have tried several combinations and none work. The check light turns on about a second after the key is put into the ON position, regardless if the pedal is depressed or not. I have tried WOT x 5 -- IDLE x 5 -- WOT, IDLE x 5 -- IDLE, WOT x 5 within the 5 second period and none work.

The check light will just stay ON and nothing happens.

What do you guys think?

I think mine doesnt work either and It came about early 88 to fully be readable

Oh and also, I unplugged the o2 sensor and ran the car for about half a minute today. The check engine light didn't even come on. I take it that's not good?

Bump.

Are your S.I. batteries in good shape?

Not certain that they are, however the check light stays on if you put the ignition into ON and not start the car.

Can the SI batteries still be a source of trouble?

I have the same problem with my 86 325es. I can't seem to get my ecu to throw out any fault codes. I've followed the Fault Code article and everything pyro-rwd tried, but nothing. I have checked my SI batteries (Type CR14250SE, 3volts) and both read 3 volts on my DMM. Weird thing is...I can turn the CHECK ENGINE light off via the overhead (near rearview mirror) status CHECK button. Two presses of this button will put a pause on the blinking. Is there something that I have to reset in order to get the codes?

you have now entered the zone Luke.