P0344 codes keep coming up

[sawdust123]

I mentioned this in another thread but thought that a new thread may be in order now that a solution may be at hand.

Here is a rundown of my issues.

Several weeks ago the MIL comes on (in the 2003 GT) with two codes coming up (Cam and Crank sensors). Car runs but with less power and occasional misfiring. Both position sensors were replaced.

A few weeks later just the p0344 code comes up. Mechanic can't find anything, resets the computer. I drive ~1000 more miles with no problem. Pulling out of the driveway on Saturday the MIL comes on again with p0344 code. I delete the code and drive about 200 more miles with no problem. Yesterday the code comes on again. I try reseting it one more time but this only lasts about a quarter mile. Goody! My intermittent problem may no longer intermittent. Maybe we can fix this sucker once and for all.

My mechanic has been pouring over the wiring for several hours since yesterday. Now he seem pretty sure the problem is actually in the MAP sensor. Apparently a short in that sensor will cause other sensors to give bogus readings. I haven't seen diagnosis before but he seems fairly confident in it. I am certainly looking forward to having a working vehicle agian.

BTW, I picked up the Can-Tech OBD reader/EOBD scanner tool from Harbor Freight (item 98614). What a great tool! It doesn't just give you the codes, it explains what they mean. It also gives you great prompts. For instance, the first time I used it, I accidently turned the key in accessory mode, not ignition mode. After a few seconds, it told me to verify the key position. It is so refreshing to find a device with a friendly UI.

[sawdust123]

My mechanic was wrong. The only thing left I can think of is the engine computer or maybe they installed a bad camshaft sensor.

[sawdust123]

Well, there is a TSB about false error codes and the solution is to reflash the engine computer. However, I already had the latest s/w on my computer and I still have the problem. My next step is to bypass the wiring harness.

[Hooligan]

Here I thought you had a "Eureka" moment, thanks for the info tho, good luck.

[Type111]

Any update? Did you ever track down the cause of the P0344 code?

[sawdust123]

Well, it is finally fixed.

The scanner helped me narrow down exactly how to duplicate the problem. All I had to do was rev the engine north of 2000 before the car had reached operating temperature. To avoid the MIL coming on, I would just wait till the car had warmed up before driving. It brought back fond memories of the carburated cars of old that didn't need no computer with fancy sensors.

As it got colder the problem got worse. I went out of town for 4 days and left the car with the dealer with instructions on how to duplicate the problem. After 8 days the dealer had run out of things to do. They had checked the harness, check the sensors, substituted the computer, etc. Nothing worked. Out of desperation they tried another camshaft sensor. That worked!

The thing is the sensor tested OK. Also, why was the problem temperature dependent? I may never know.