Emissions Test - PCM Memory

My son’s Mazda MPV wouldn’t complete an emissions test last year so the dealer got a waiver. The dealer had it 5 days then. Penndot won’t give a waiver this year since it gave one last year. The van has been at the dealers 5 days now. The dealer has been in touch with Mazda and done everything that Madza has told them, but the dealer cannot get it to register and pass 5 of the 7 tests. Yesterday they got it to register 4 tests. Today 3. In addition, when the engine is shut off, the PCM loses all its data so the van has to be tested after the van has been driven but while still running. The dealer has checked the PCM, the wiring, coolant sensor and everything else Mazda has told them to check with no success. They and Mazda say they have never seen anything like this in all their years. I’m at the mercy of Penndot and face the possibility of having to junk this car because of something out of my control and for which no one has a solution. Anyone have any ideas for a fix to this problem. Thanks. Patrick

I would drive the car with the computer hook up and check if the car is going into close loop. I would also drive the car with another ECM installed, heck, the dealer should have one on the shelf. Sometimes the problem is smiling at you…

Thanks for your input. I will run it by them. Patrick

Today 3. In addition, when the engine is shut off, the PCM loses all its data so the van has to be tested after the van has been driven but while still running.

This is the primary problem IMO. You will never get all the monitors to register as ready because some of the tests require multiple start cycles to complete. It sounds like one of the power leads to the PCM is bad such that the volatile keep-alive memory is losing power with key off. Id’ first check the wire that supplies constant power and if it’s good, the PCM has a fault.

Thanks for the input, I will pass this info on to them.

Why is your PCM not being replaced under either factory warranty or Federal 8yr 80K warranty? If you had listed year and mileage I would not be asking this.

Don’t junk it, there are some states that have countys that don’t require emissions testing . I think Ohio is one of them, put it on ebay and sell it there.

PCM was replaced, in 2006 I think, when just under 80K and still under warranty. MPV is a 2000 with approximately 117K on it. Thanks for asking.

Thanks for the info. I will consider it.

I am lost,are you saying the problem existed in 2006 and a PCM was replaced under the 8yr 80k (nice to know this really happens) and the problem went away but now in 2009 the same problem has returned?

I think you are refering to the monitoring ststus of the PCM not the memory.

When you say “loses all data” you must mean current and history codes, am I correct?

In 2006 the engine light was on and I had the plugs and cables replaced, an intake valve and one other thing. Upon completion of the work, the engine light was still on so the dealer replaced the PCM and then the light went off. Last year, when the waiver was received and this year when I went for the emissions test, the light was not on. When I say loses data when it’s shut off, I am just repeating what the dealer said. I don’t have the technical knowledge to discuss this like I would like to, but I guess the answer to your question is yes. We brought it home for the weekend so my son could use it, but it goes back in tomorrow. The sticker expires Wednesday.

Lets keep at this,what is the status of the replaced PCM, is it showing the same symptons of the old PCM? It would be really odd that your car has had its PCM replaced and then needs another one. Its seems that that is exactly what you are saying,the PCM that was replaced in 2006 is giving trouble now in 2009.

Or lets go another way,why did the car need a wavier last year? why could the problem that generated the need for a wavier not be fixed? what was the problem that generated the need for a wavier?

Clarify something here. You state that in 2006 an intake valve was replaced, along with a few other things including the PCM, at around the 80k miles mark.
Surely you don’t mean a cylinder head intake valve?

Did this vehicle suffer a timing belt failure?

Write your state rep and demand satisfaction. While you are at it, ask him to abandon emissions testing or prove that it makes any difference in air quality…

The “failure” rate for these “tests” is so low, repairing the failed cars represents such a small number, the improvement in air quality is insignificant…Emissions “testing” is a complete waste of time…

I agree, but any action is so slow here. We don’t even have a State budget yet.

I wasn’t sure so I asked the dealer. Said they had to pull the records , but I never did get the info from them. However, I did just hear from them about the testing and Mazda told them that since they have tried everything else to no avail, to put a new PCM in. That will happen on Wednesday.

Does this mean Mazda pays?