INTERMITTENT ASR LIGHT AND LIMP MODE

[r44raven]

My indi is trying to track down a very intermittent problem, where the ASR light will randomly illuminate, and the engine drops into limp mode. Turning the engine off/on cures the problem - until the next time, which could be almost immediate, or 12 months away!

Fault reading indicates a problem with the front driver's side ABS sensor - but at the same time, we're getting ABS Code 30.

My questions are:-

Does an ABS sensor fault trigger Code 30?
Does an ABS sensor fault trigger limp home mode?
Is the Code 30 a ghost code, which then triggers limp home mode, or does the limp home mode trigger the Code 30?
If the Code 30 is real, what am I looking for?

Over the years, all the usual suspects, i.e. wiring harnesses, late date ETA etc. etc., have been renewed.

Any suggestions would be gratefully received.

 

[gsxr]

Limp mode triggers ASR code #30, which is a generic ghost code that can be ignored. It is a red herring.

Are you also getting ASR code #2 or #25 for left front VSS (L6/1), driver side ABS / wheel speed sensor?

Look at the E-GAS/EFP module faults, this will tell you what is causing the limp mode.

 

[r44raven]

Thanks for that, gsxr!

I've sent your reply to my indi for his comments!

Interestingly, I do have a brand new E-GAS module I could try for grins?

 

[r44raven]

Limp mode triggers ASR code #30, which is a generic ghost code that can be ignored. It is a red herring.

Are you also getting ASR code #2 or #25 for left front VSS (L6/1), driver side ABS / wheel speed sensor?

Look at the E-GAS/EFP module faults, this will tell you what is causing the limp mode.

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Sorry, should have asked before!

As I understand it, the front ABS sensor fault would not have triggered the limp mode?

And also, did the limp mode trigger the ASR light, or did the ghost Code 30 trigger that?

Thanks in advance.

 

[gsxr]

Correct - an ABS sensor fault should not have triggered limp mode.

The limp mode triggers both the ASR light and also the ghost code #30.

Limp mode is due to a throttle control fault of some sort, completely separate from traction systems. I assume that because there is no ETA / EFP fault light on the dash, MB decided to have limp mode trigger the ASR light instead? The new E-GAS module likely won't cure the problem. Pull codes and see what shows up. You may need to clear codes and drive it until limp mode occurs again, if there are multiple faults.

 

[r44raven]

Thanks for that! It's really helpful. I'll keep you updated.

 

[jaymanek]

I would follow gsxr advice and look for codes in other modules first... but when i had a similar issue and codes were sending me around in circles, it ended up being the transmission loom. I guess some kind of short, although i never actually found a physical issue with the wires...

took me 2 years to find and in the end it became an educated parts swapping exercise until the issue was cured. Hope its more simple for you!

 

[tanger]

OMG this was what my indy just spent the last year+ hunting down! Took apart the wiring harness, replaced the ETA, the ASR module, and the Air Mass Flow sensor. It turned out that the renewed ETA was NOT completely fixed. Put in another rebuilt one (from someone in FL?) and it fixed the issue. The rebuilder of the original ETA swore it was fine but it was not. I can't remember where the first rebuilt ETA was from, but maybe your indy should call Gary or Ed at Johnson Motorcars in Orange County, CA. They were the ones working on it.