ECU Self-Diagnosis *TESTING*

[lino]

I was away from my Q for a very long time and now that I'm back I wanted to do some testing. I already have a very long to-do list of things I'm aware of, but it's the things that I don't know about that I'm after now.

Here are some of the problems I've noticed so far:

No power - feels like the engine is revving and racing, but the car is going nowhere. I feel like a 3cyl can overtake me with ease.

Idle- I warmed up the car and noticed that the idle surges by itself up to 1500-1800rpm range and drops back to normal after maybe 10 sec, all by itself. It did this twice.

Fuel- When I warming up the car, I noticed there was a slight smell of gas in the car and a noise coming from the rear speaker area. I opened the trunk and noticed a loud sound coming from the top of the fuel tank.

Transmission- shifts hard at times and doesn't shift well or change gears at the appropriate times. If I press on the kick-down switch the engine races (takes forever to accelerate)and the transmission doesn't shift and there is hesitation, like the car is choking, (kind of like fuel starvation or electronic signal cutting the fuel or power... I'm not sure)

So late last night, due to my serious obsession with this car, I decided to check out the ECU. I removed the glove box and the trim piece below it, pulled the carpet trim piece out, removed the ECU connector 10mm screw, and then the 2 philips screws that secure the ECU. Then I repluged the connector and started the self-diagnosis.

First off, I don't have a Check Engine light lit on the dash. When I did the testing, both the Check Engine light and RED L.E.D. did not light up, which means Bulb Check is OK (MODE I). Next, I switched modes and got a Code 55, which is supposed to mean No Malfunction (MODE II).I forgot to do the Exhaust Gas Sensor Test .

Next I did the Automatic Transmission Self-Diagnosis:



and got the following:



I need your help
Modified by lino at 2:22 PM 10/28/2006

[goody90q45]

Going back to the bulb check in Mode 1. That is done when you first turn the ignition to the on positionand is meant only to check that all the dummy lights are working on the speedo cluster. From your post it sounded like you might have rotated the ECU screw once for the bulb check and a second time to read the codes.

Can't tell if this is the first time you've done this but here's the sequence:* Turn ignition to the on position. Red Light on ECU should be on.* Turn screw on ECU fully CW, wait 2 seconds, turn screw fully CCW.* Read codes.* When done reading codes, reset ECU- Turn screw fully CW, wait 2 ceconds, turn screw fully CCW. ECU will now flash code 55 until you turn off the ignition.

Good luck

[lino]

Can't tell if this is the first time you've done this

Yes, it was my first time.

From your post it sounded like you might have rotated the ECU screw once for the bulb check and a second time to read the codes.

I can't remember if the ECU Red L.E.D. came on or not, I did however turn the ECU screw fully CW, waited a few seconds, and turned screw fully CCW. I did this three times to switch modes and be sure. Doesn't mean that I didn't do it wrong.

This is what I basically did:

[goody90q45]

What I meant to say was you're only going to get the code the first time you turn the screw. After that you will get code 55. I would have thought if you had a bad TPS it would have shown up as a ECU code but not necessarily lit up the CEL.

[Q45tech]

The TPS output voltage feeds TCU and ECU in parallel, could be a bad connection at TCU or a bad TCU incorrectly interpreting the TPS voltage or an actual bad TPS sensor or TPS connection or calibration.

Why you actually must read the TPS voltage sent to TCU and ECU.

[elwesso]

i had this EXACT same problem. It would throw a code at the TCU for the TPS but not at the ECU... It ended up that the ECU harness connector was not fully seated on both sides.... it needs to be FULLY SEATED on both ends otherwise it will mess up everything... Press on the ends with your finger to get it to set in all the way....

Have you put in fresh gas since you returned?

[lino]

i had this EXACT same problem. It would throw a code at the TCU for the TPS but not at the ECU... It ended up that the ECU harness connector was not fully seated on both sides.... it needs to be FULLY SEATED on both ends otherwise it will mess up everything... Press on the ends with your finger to get it to set in all the way....

Have you put in fresh gas since you returned?

I'll disconnect and reconnect the harness connector.

I did not put fresh gas since I returned. The car is almost full.

[lino]

After disconnecting and reconnecting the ECU harness, the AT Check came back with an OK.