Ofeelya

Blinked out ECU fault codes and came up with 2111 (RPM Sensor). Car stalls when running, so I'm pretty secure with that one. But it didn't blink out 2112 (crank/reference sensor). The car won't start when hot. Cleared the codes and tried again with hot engine (wouldn't start). Still no 2112. When the car doesn't want to start after it's been driven and is hot, I was led to believe that the crank/reference sensor was the culprit. Would a heatsoaked RPM sensor also cause the car not to start when hot? I will be replacing both sensors, but I'm just trying to get an idea of diagnosing problems with these cars.

Also blinked out the transmission fault codes and got 2314 (engine/transmission electrical connection). To correct the problem I'm supposed to check the connection wires between the ECU and Transmission Control Unit. Where might they be?

All output tests were okay.

Any thoughts are much appreciated. Thanks again!

20VT90q

I know how to do the ecu codes, but how do I obtain the trans codes?

Ofeelya

The transmission fault codes blink out in the same manner as the ECU fault codes. Keep the +/- ends of the LED in the same position and short the system with the jumper wire as you would to obtain the ECU fault codes. Look up at the P-R-D-3-2-1 lights in the dash. They will blink in the same fashion as the LED. You'll get a 2.5 second blink where each PRD321 light is lit up and then it will proceed to blink out a code. A blink consists of all the PRD321 lights lit. You'll get a 2.5 second light up followed by a 2.5 second pause (that repeats itself over and over) when it's done. It'll also blink out 4444 when there are no recorded fault codes.

audiqv8

Review my previous post

Check the tach when you have a no start condition. Does it bounce when you crank the engine? If your engine stall while running then it is most likely the speed sensor. And yes a heatsoaked RPM sensor will cause a no start condition.

Codes 2111 2112 and 2234 will sometime be blinked out when the ignition is on, but the engine is not running. The ECU will reset these codes once the engine starts.

The transmission control unit (TCU) is located behind dash on the driver side above your left foot right below the ECU.<ul><li><a href="https://forums.audiworld.com/v8/msgs/28777.phtml">https://forums.audiworld.com/v8/msgs/28777.phtml</a</li></ul>

v8phil

I spent 1/2 hr yesterday blinking out the codes. Unfortunately I need more practice, getting used to going through the sequences. (I still havn't seen my PRND321 blink yet)
Like you, my car blinked out 2111 at first. Now it just blinks the 4___ series. I did note of interest @sjmautotechnik that he talks of the car blinking out the 2111/2112 or 2234 code in some cases with the ignition turned on (1/4 way down the page). He doesn't explain why though. I've added the link to this thread, hope it works. If this is old news to you I apologise, but if you can make sense of it, please pass it on.

Phil
90 V8 Pearl White
90 V8 Blue<ul><li><a href="http://www.sjmautotechnik.com/ecufv8.html">http://www.sjmautotechnik.com/ecufv8.html</a</li></ul>

spdfrk135

audiqv8...on my '93 V8 ECU &amp; TCU are behind driver side dash knee pad (must remove to get access to both)in the upper left.Is '90-92 located in center console?-Bill

audiqv8

<center><img src="http://pictureposter.audiworld.com/36396/audiv8-mod.jpg"></center><p>
Thanks spdfrk135+ for correcting me.

My mind was on something else. You are correct, the ECU and TCU (items 6 and 7) are located behind drive side dash knee pad.

Ofeelya

The tach did bounce. That's why I'm so baffled. I realize that this system of diagnosis is probably not fool proof. I've blinked the codes numerous times and continue to get only 2111 from the ECU. I'm replacing the RPM and Reference sensors. That should fix the problems. So I'll leave a thread letting you all know how things turn out. If it's not good, I'm selling this thing and buying a Lexus!

Ofeelya

He says it may produce those codes with the ignition on, but without the engine running. Mine gives me the code with the engine running. I'm not doubting the RPM sensor is at fault. And audiv8q answered my biggest question. Yes, the car will not start when hot when the RPM sensor is at fault.

spdfrk135

audiqv8...tnx for posting that exc. dash illustration...I'm having prob. with HVac on my V8 &amp; that will help me identify diff. subassy"s.-Bill P.s.-you going to AudiExpo in Sprngfld,MA this wkend?