I have a 2002 Mazda Tribute v6 that is giving me problems. This car has been relatively sound and maintenance free with the exception of a new battery, a tune up, and regular maintenance. It has less than 90k miles on it.

Recently, we noticed an intermittent, loud-screeching, or metallic-grinding noise coming from the engine. It lasts for a few seconds at a time and usually only occurs while in Park or Neutral while idling. We also got an engine code of P1633 Battery Overcharge Fault. A mechanic friend noticed that the voltage was high, indicating a bad alternator. The loud screeching noise could be related to bad alternator bearings.

We had the alternator replaced, which is not an easy job on this vehicle.

After leaving the alternator specialist, we noticed the check engine light was still on. This is odd because the radio stations were defaulted, so they must have disconnected the battery. The engine light went out before I could have the code read. It has come and gone a couple of times since, but the engine sounded better and the sound was gone.

A couple of weeks later, the noise came back. Only once though, and for a few seconds. It almost sounds like the starter is being engaged while the car is running. We are going to take the car back to the alternator shop but are a bit worried that this could cost us more than we bargained for.

This morning, while backing out of the garage, the vehicle stalled. All electrical systems died and the vehicle would not restart after several attempts. After attempting to push the vehicle into the garage with no success (uphill), we tried the ignition and it started.

I was afraid to drive it after that. It now sits in the garage.

Any suggestions?

Thank you,

GinoRP

 

Last night I recently realized that the P1633 is a dealer specific code. Although this is a Mazda, the vehicle is actually built on the Ford platform. The dealer-specific engine codes vary by car manufacture:

Ford: P1633 KAM (keep alive memory) voltage too low
Masda: P1633 Battery voltage - overcharging

Now I know it hast to do with the PCM. I checked all fuses, grounds, harnesses, and electronics. I can't find anything that would contribute to a low voltage condition at the KAM. I don't even know if the KAM is in the PCM.

I did find a recall on the PCM that dealt specifically with stalling on deceleration, but that seems to be more related to the programming.

I hear that replacing the PCM requires a dealer because of the security keys.

If anyone has any suggestions, please feel free to interject. All discussions/comments are welcome.

Thank you,

GinoRP

 

Ok, Since then we have replaced the Alternator which seemed to correct the problem for a little while, but then the code came back.

Just finished replacing the PCM. Same problem.

HELP!

 

I don't know what else to do and the mechanic that replaced the alternator keeps sending me to other mechanics to spend more money on work that doesn't correct the problem.

The registration is now expired because it can't pass smog without the check engine light off.

 

I wish I could help, but this is out of my league.
There are a number of TSB on the electrical system. Find them here:http://www.ford-trucks.com/tsb/tsb.p...2002/d-TRIBUTE

Best of luck!

 

Thanks for the help. I actually made some headway today. I found out that pin 55 on the PCM is supposed to have constant power. There is no power on pin 55, but all of the fuses check out good. I can't figure out which fuse the PCM draws constant power from for the Keep Alive Memory. My next guess would be to check the wire for an open, but the harness is wrapped tight. It's hard to follow where it goes.

 

Actually, I brought the car back to the mechanic who replaced my alternator (the guy that made me unnecessarily replace the PCM in the first place) and he said that there is close to 10.5 v (slightly less) on pin 55 and he is convinced that it is the PCM still. 10.5v seems low since the battery measures much higher and all the technical references specifically state "at least 10.5v". The only difference is that I checked with the chassis ground and he checked with the harness ground. I'm starting to think that perhaps I measured it wrong or wasn't making a good connection.