CEL light and code reading

[Benzadmiral]

Hey,a ll,

My MB C230's Check Engine Light is back on again (an ongoing issue with my transmission; at least that's where the symptoms are cropping up). I can take it to have the codes read before I start throwing parts at it.

1) Can a "generic' scanner, such as Autozone's, read all the codes?

2) More important, can the codes still be read if the light has gone out on its own? I've been told no, that the MB 722.6 transmission doesn't store the codes. True?

TIA!

 

[NYEngineer]

On both my Yukon and my wife's Saturn, once the light goes out, there's no code. I just bought an Innova code reader. It was under 150 bucks and I think it works nice.

 

[wiswind]

If the CEL has gone out, then there have been a certain number of drive cycles without the error happening again.
Sounds like you may have a intermittent problem.....or one that is right on the edge of the specification for tripping the CEL.

AutoZone uses a "Generic" code reader, just as you would buy.
They will read the "P" codes.
If you have them read the codes, make sure to get the actual code....not just a description.
Most people have no clue about the numeric code, so rather than confuse the customer, they normally won't tell you unless you ask.
P0xxx codes are pretty much generic across all manufactures.
P1xxx codes, from what I have read,can vary a bit between manufactures.

Take note, one failure that causes a code can cause other codes.....as the OBDII system tries to compensate....

Another note......as example, my vehicle does not monitor fuel flow or pressure.....so there will be no CEL that indicates a fuel problem directly....but other CEL codes could come up.

Another hint, once you get a "P" code, do a internet search on the code AND your vehicle.... "P0304 Ford Windstar" to find what likely causes / solutions of the code would be on your particular vehicle.

 

[paul_e320]

Quote:

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Hey,a ll,

My MB C230's Check Engine Light is back on again (an ongoing issue with my transmission; at least that's where the symptoms are cropping up). I can take it to have the codes read before I start throwing parts at it.

1) Can a "generic' scanner, such as Autozone's, read all the codes?

2) More important, can the codes still be read if the light has gone out on its own? I've been told no, that the MB 722.6 transmission doesn't store the codes. True?

TIA!

---

As someone else said, the scanners that you can buy/use only will read the P0xxx generic (standardized) codes, and some, but not all P1xxx codes. If you do read a P1xxx code that's related to the MB transmission, it can only tell you that the transmission's TCU is holding a code. The only way you can find out transmission code is to go to the dealer or an indy that has the Star Diagnostics tool. Check out the MB Club of America's site as they have a list of indies by state.

Regards,
paul...

 

[Benzadmiral]

When the CEL first came on (yes, it's a *very* intermittent problem!), AutoZone's scanner read a code P1747, which indicated something in the transmission solenoid. I took it to the dealer, who got the same code . . . but couldn't reproduce the problem, and so couldn't solve it.

Since then the light has winked on twice or three times, and has always gone out within a few hours. Maddening.

It seems I get this problem *only* when, upon starting the car from cold, the idle is immediately too low. By that I mean, instead of first idling at about 1000 rpm then dropping down to 550 within a few moments, the car starts and almost instantly drops to 600, then 550. Almost invariably, if this happens, the car will refuse to shift correctly and will slam into gear (it feels almost as if somebody is rear-ending me!).

From what I've read here, this sounds like an air mass meter going bad. But before I throw a $250-400 part at the problem, I'd like a bit more information!

I'll stop by AZ this afternoon and see what they can find.

 

[Benzadmiral]

Update: I stopped at AZ. The light had gone out, but the scanner read it without trouble. The code was the same as before, P1747. Nothing else, nothing relating to the AMM.

Weird. At this point, I guess I'll keep driving the car (which is superb except when this crops up) and see what happens. . . .

 

[Merkava_4]

Quote:

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P1747 Electronic Gear Selector Module: Defective Interaction of CAN

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Robison Service

 

[Benzadmiral]

Thanks, Merkava. Odd that nobody at the dealer mentioned this code description to me when I was there last month!

I'll run it by my independent guys and see what they say, and if there's any way to be sure this will solve the problem. I guess it means replacing that pesky/pricy controller unit, hey?