[M3RacerX]

Just a helpful hint about DTC, when you disconnect the battery you only remove the light indicating a code on the dash it does not re-set the DTC itself. The ECU will hold it in memory until the issue is resolved. You can also see this in the monitors.

Continuing to disconnect the battery may cause other issues and is not the correct way to diagnosis or re-set DTC.

The internet is full of inaccurate and poor information often MYTH often supported by other's that read it and pass on the information as valid or empirical.

The first thing I recommend to do when any DTC light is activated is properly acquire any and all DTC with a quality Diagnostic Scanner, note them and re-set and run at least one complete engine cycle and see which DTC are activated. Then look up the DTC and what the procedure is to verify the problem area.

 

[M3RacerX]

Some DTCs don't activate with one engine cycle. The IMRC DTCs take 4 to 6 engine cycles to fully activate. BUT, a good scanner will show you that there are pending codes for those faults before the check engine light comes on.

:bigok: ^^^
Yes and that is in a round -about way what I said... "quality scanner"! There is also something else I mentioned in that response as well having to do with DTC.
I do try my best to explain things on a forum but seldom need to go into exacting procedure details when it comes to most responses to DIY.

We use a few different ones at the shop depending on the need. The flat rate charge of one hour encludes all dignostic and determination of exactly what the issue is. We dod not go over an hour for any dignostic work to find a problem. The exception is if a sensor need to be checked and it is buried in an area that takes labor time simply to get to it like 1 hour or more R&R.

 

[M3RacerX]

That really depends on the car, typically only really new ones that have the ability to store permanent DTCs do that.

Ok sure but...IMHO we are cutting fine lines with regards to information
I did not think I needed to give all the years and models that do considering this forum and the thread it was asked. :wink2:

In general as I said disconnecting the battery to solve an ECU problem is a bad idea and as far as I know never a procedure in any Factory Service Manual,TSB,aftermarket repair manuals or even ASE Training that I am aware of. :nerd:

I do notice that your are a "mechanic".

 

[M3RacerX]

*You're:nerd:
Occupation Mechanic

Yup and at the shop I wear a pocket protector ......:nerd:

Kidding..... :wink2:

 

[M3RacerX]

From what I read the proper way to determine what caused the DTC is and has not been done? If a part changed corrected the problem causing the DTC it would self clear on its own in a couple of days of normal driving or between 1-5 complete ECU start up run cycles.

Hopefully the clearing is done using a Diagnostic tool. And if the Diagnostic tool has the capabilities to view the monitors that can tell you a little more what is going on. The monitors from about 2000 and newer cars will hold fault information until they are corrected.
I have not yet seen any large production vehicle that will permanently store any and all DTC's that are generated in the ECU service life?

Guessing and changing parts seldom correct problem and many times creates new ones.

There is NOTHING in this thread that at this point would indicate through following a better and more correct diagnosis procedure the need for a smoke leak test yet!

 

[M3RacerX]

:laugh: I did not think that response was posting. The site kept closing and refreshing on me as usual when I am at the machine shop and all metal building around. I finally gave up and logged off without posting it. To bad because that was NOT the draft I wanted to post but its there now. :laugh:



I do not recomend the use of those types of Diagnostic tools. I do recomend any Diagnostic device that connect via a cable directly to the Diagnostic Connector.

What I do.... I first use a proper Diagnostic tool and access the Diagnostic connector and see the current DTC's. Note them and then clear only them. I then will restart and do a short drive or depending on the DTCs let the engine idle to see if the the engine caution light reappears. At that time I will will go back and access the ECU at the diagnostic connect and see what the DTC's are and compare to the original. Then looking what each one is and seeing what the proper diagnostic solving information is for each DTC. Very few DTC ar as simple as what is found on the internet. You need to use a Factory Service Guide and find the procedure for e the problem solving. We call this a problem solving tree. I am sure you are familiar with that term?



Anything less and you will be spending lots of time on a thread on a forum with many giving the guessing games of how they solved there problem which they are sure is the same as yours and have you changing parts and in the ends someone always wins the game and solves the OP's problem.

Since 1995 vehicles are no longer as easy to diagnosis for DIY as previous years. I am not sure even the days of distributors and carburetors DIY fared any better.

The first thing you need in your garage tool box is a Diagnostic Tool that can read at least engine codes from the PCM/ECU or what ever you want to call the Engine computer control unit! ABS and TCM are not really necessary and probably because problems in those area's your need to have training or some experience to solve anyway.
The next and maybe the first is a FACTORY SERVICE MANUAL hopefully one that has ALL the updates . Repair manuals like HAYNES and Chilton are not as good as they use to be. That may be an opinion of mine, however I owns about 90 of them and from 2000 and newer I simply stopped getting them. I now rely mostly on AllDATA. But that requires a service charge/contract to use them.

That said I read what you have done and you simply missed the target with the part changing guesses. Sure you can always say the miles and why not change them but really you don't do this until the problems are solved first. Then ya... go ahead and change a few parts as an act of preventive maintenance.