Codes 19 and 20?

[Gregstein]

'94 E420 - Check engine light - checked analog codes and :

OK, I checked code 19, it says "Injector open or short circuit or emission control adaptation at limit"and code 20 is "Vehicle speed signal missing".

I reset the codes and then after two trips code 19 came back on. Anyone have any idea what this means, or what needs to be checked next?

Note: The car appears to run fine (though the accelerator has always been a bit touchy - I've owned the car for about three thousand miles, so I'm not sure how it should be).

Thanks -- Greg

[deanyel]

If your speedometer is working no need to worry about #20 unless/until it comes back. #19 could be bad wiring harness if original. Next step would be to check codes on other pins to see what else you get.

[Arthur Dalton]

Code 19 is an adaptation limit excess code..it is also common on that chassis b/c the ECU had a small percentage +/- lee-way for limits before popping the code. That can be expanded to a larger % by changing the chip in the ECU [ do a search on code 19/JimF here]...

..but , before going that route, you want to check for BOTH vac leaks AND fuel pressure. A vac leak will cause ECU adaptation beyond limits to correct for the lean condition caused by the leak, and a bad FP regulator will cause a rich condition by leaking gas into the vac port of the reg or allowing too high of a FP. That rich condition will also try to correct , but if the system has to correct too much , same deal...pops the limit reached/exceded code.
So, I would check for both vac leaks everywhere and then I would check the FP regulator and pressure.
If the engine has many miles , then it is just in need of a higher adaptatation value than the ECU is capable of and the chip w/higher % limit can be done..but don't do that until you have checked the above first, as you may not even need higher adapations % limits.


EDIT *

Jim F and I were typing in the same time frame, so his Posting is the search notation I was referring to............he has those chips, if neeed.

[Gregstein]

I've got a spare wiring harness, so I'll go ahead and replace that as well as check for vacuum leaks and fuel pressure.

Is there a way to double check whether or not that chip is the problem?

Thanks! -- Greg

[JimF]

Originally Posted by Gregstein

I've got a spare wiring harness, so I'll go ahead and replace that as well as check for vacuum leaks and fuel pressure.

I certainly would make sure your vacuum lines are good. Don't forget the 'nipples'; they get small cracks and are hard to spot. Might just replace all of them.

The DTC#19 is not associated w/ a wiring harness . . . but if it NEVER been replaced, now is a good time. If it HAS been replaced, there's no need to do it again.

Originally Posted by Gregstein

Is there a way to double check whether or not that chip is the problem?Thanks! -- Greg

Not until you remove it from the fuel computer. I can assure you that's it's not the improved version.

[Arthur Dalton]

If you find vac leaks or FP faults, just clear the code and run it ..if it was cured , the code will not come back up b/c you have solved the problem and the system has re-adapted within the limits.

However, as JF has stated , they found that as the engine wears , the adaptations limits of the original were found to be too close a limit for normal adaptations and by upping the +/_ percentage of his modofication, it gives the systsem more limitation % lee-way.
I have even seen a dirty a/filter bring on a code 19 with the OEM system..
But is your engine management system is in real "On The Money" running conndition, [ meaning no leak, wear, fuel mix, etc], then it will run within OEM limits just fine. There are many out there that do not bring on a code 19 and they have the OEM set-up.
A trick to do after you find any leaks or FP problems , is to get that code 19 cleared and then after you get a single Flash [ designating No Codes Stored], you then wait 2 secs, press button 6 sec , turn off key for 2 secs , on for 10 secs and start car...this will clear the adaptation memory back to mean [ zero] so the ECU does not have to readapt with drive cycles..you will then know you are starting with a zero base-line and if it hits adaptation limits after that memory clearing, then it has come from zero, not from the OLD adaptation memory that was set before the remedy...
Less chance of getting a false code while the system re-adapts that way..

[JimF]

Originally Posted by Gregstein

'94 E420 - Check engine light - checked analog codes: OK, I checked code 19, it says "Injector open or short circuit or emission control adaptation at limit"

Thanks -- Greg

Check my main web page (about half way down) for details on the #19 problem and a solution.