I am having gauge issues and I have pretty much traced it back to the PCU. The car runs fine with the original PCU, except for the bogus oil pressure and volt readings. I replaced the PCU with a used unit, it would only putt once and not start. I got a second used PCU and it fires once and that is it. I put the old PCU back in and it fires right up!

The service numbers are the same on all 3 units, am I doing something wrong? Sure there is the possibility that I have two bad used PCUs, but unlikely. Do I need to leave the PCU in the car powered up for a while? I pulled the codes and there are none.

Did you do a security learn procedure on the PCM'*?

I was thinking the same thing.

1. First, insert the ignition key and turn the ignition switch to the “On” position (Do not start the engine). Leave the switch on for 11 minutes. The security light may flash or be on steady during this 11 minute period. Make sure the light is no longer on or flashing before proceeding to #2 .
2. Turn the ignition switch off for 30 seconds.
3. Turn the ignition switch to the “On” position (as in step #1) for 11 minutes again.
4. Turn the ignition switch off for another 30 seconds.
5. Turn the ignition switch to the “On” position for 11 minutes a third time.
6. Turn the ignition switch off for 30 seconds one final time.
7. Turn the ignition switch to the “On” position one final time and wait 30 seconds.
8. Attempt to start the engine. If the engine starts and runs normally, the relearn is complete. If the engine does not start, check for trouble codes and address them before attempting the relearn procedure again.

No and I don't know what that is. That may explain it, can you provide details?.... oops, spoke too soon. What happens if I wait longer than 11 minutes in between or is it at least 11 minutes?

No idea, I say have a watch and do it at 11 min. Also, have your battery on a charger. This is hard on the battery.

OK, I did the security learn but I may have screwed up. I accidently did 10 minutes the first time instead of 11, I finished the process anyway. Unfortunately, no change. I will try again later and do it by the book and see if it changes. I did not however have a security light at any point.

I was smart enough to put it on charge during this, my battery is weak anyway.

Did you switch the chip from your first pcm to the other pcm? It could be your chip hasn't been put into the newer pcm. When I went to another pcm I had to swap out the chip. Well let us know and good luck.

Post a picture, I'm not sure if the 98 has a changeable CASE chip.

The Security Relearn procedure Dan piosted is not quite right.


The procedure is
1. Insert the ignition key and turn the ignition switch to the “Start” position The engine should not crank over. Let the key fall back to the "On" position, watching the Security light..it should go off in 10 minutes.
Once it stops flashing or goes off, go to the next step.
2. Turn the ignition switch off for 10 seconds.
3. Turn the ignition switch to the “Start” position (as in step #1) and let it fall back to the "On" position for 10 minutes again.
4. Once the security light goes out or stops blinking. Turn the ignition switch off for another 10 seconds.
5. Turn the ignition switch to the “Start” position (as in step #1) and let it fall back to the "On" position for 10 minutes again.
6. Once the security light goes out or stops blinking. Turn the ignition switch off for another 10 seconds.
7. Attempt to start the engine. If the engine starts and runs normally, the relearn is complete. If the engine does not start, check for trouble codes and address them before attempting the relearn procedure again.[/quote]

Edit: Forgot to mention, at no time should the starter engage until step 7. If the starter engages then this procedure is not needed.

Starting and then stalling out quickly means the security system is engaged and different than the one this procedure applies to. In your year, I do believe this procedure should work, if it does not, then the VATs believes it sees an incorrect resistance value in the key.

According to that description the START should not work. I don't have that problem, it will turn over with no problem, I also have no SECURITY light.The description does however sound right, it fires once and quits.

My PCM does not have any litle doors or windows that I would expect to see if there was a chip to replace. Mine is a solid alominum box but there are screws on the entire case but I will look closer.