Star Diagnostics vs pulse

[73eldorado]

Question for the group. I am chasing an ASR light with limp mode issue on a 1995 sl500 and I would like to know if I should take my car to my Mercedes dealer to have a scan done with STAR to help pin point my problem. I have the pulse reader which reads pin 6 code 30 and pin 7 code 2 and code 3.
I have replaced the following
- upper and lower wiring harness
- rebuilt eta from Don Rodon
- brake light switch
- accelerator kick down switch
- neutral safety switch
For a while I was able to clear the codes and use the car for a number of weeks before the ASR light returned. Now the light comes on at start up with limp mode right after the codes have been cleared.
Will STAR help me??

 

[gerryvz]

A Star Diagnostic (HHT or HHT-Win if used on a laptop) will very definitely help you with Pin 7. Pin 6, not really.

Pin 6, Code 30 is a common code with limp-home mode and isn't anything of and by itself. A STAR scan isn't going to tell you anything different with regard to this particular code (or Pin 6 in general).

Pin 7, Codes 2 and 3 would very much benefit from a STAR scan, or another type of reader that can give you the detailed sub-codes. Those sub-codes will definitely point you in the right direction as for further diagnosis. Try to find a good indy shop to read the codes, as it may be cheaper than a dealer, unless there are none in your area.

It does appear that you have replaced all of the common items that pertain to LHM / ASR lamps. Typically the ETA and the neutral safety switch would be the most common problems, because of the bad wiring, and/or a worn-out NSS.

Looking ahead to a couple of diagnostic questions:

• Did you ensure, when you replaced the NSS, that you calibrated it correctly with a drill bit or other small rod? This is important.
• Are you able to identify specific times/places/actions in driving the car that result in the ASR light/LHM happening? For example, after a high-speed mash of the throttle? Are you able to reproduce the situation on demand? Is it only happening at start-up, or does it stay off and then come on whilst driving?
• Have you checked the condition of your accelerator cable? If not, I would do a visual check for degradation, and possibly adjust it (or check the current state of adjustment). This can be a culprit.
• How long ago did you replace your neutral safety switch? What brand did you use (MB or aftermarket/OEM)? I have not been happy with the quality of the replacement NSSs over the past couple of years, so I am just wondering out loud if you could have a faulty one.
• Have you checked the condition (physical) of the wheel sensors and their cables?

 

[gsxr]

I have the pulse reader which reads pin 6 code 30 and pin 7 code 2 and code 3. ... For a while I was able to clear the codes and use the car for a number of weeks before the ASR light returned. Now the light comes on at start up with limp mode right after the codes have been cleared.
Will STAR help me??

Ditto to everything Gerry said above. If the light comes on at startup, before you touch the accelerator pedal, the issue will be related to pin 7 code 2 or 3. Code 30 on pin 6 is a generic / ghost code that always appears with limp mode, just ignore this.

Note that all the possible faults on code 3 are related to ETA internals. First triple-check that the accelerator cable is adjusted properly, as this can cause limp mode on startup. If so, there's a faint possibility the ETA may need to be sent back to Don for a checkup. Swapping in a different E-GAS module wouldn't hurt as a test, along with verifying the module is fully seated in the socket.

 

[73eldorado]

A Star Diagnostic (HHT or HHT-Win if used on a laptop) will very definitely help you with Pin 7. Pin 6, not really.

Pin 6, Code 30 is a common code with limp-home mode and isn't anything of and by itself. A STAR scan isn't going to tell you anything different with regard to this particular code (or Pin 6 in general).

Pin 7, Codes 2 and 3 would very much benefit from a STAR scan, or another type of reader that can give you the detailed sub-codes. Those sub-codes will definitely point you in the right direction as for further diagnosis. Try to find a good indy shop to read the codes, as it may be cheaper than a dealer, unless there are none in your area.

It does appear that you have replaced all of the common items that pertain to LHM / ASR lamps. Typically the ETA and the neutral safety switch would be the most common problems, because of the bad wiring, and/or a worn-out NSS.

Looking ahead to a couple of diagnostic questions:

• Did you ensure, when you replaced the NSS, that you calibrated it correctly with a drill bit or other small rod? This is important.
• Are you able to identify specific times/places/actions in driving the car that result in the ASR light/LHM happening? For example, after a high-speed mash of the throttle? Are you able to reproduce the situation on demand? Is it only happening at start-up, or does it stay off and then come on whilst driving?
• Have you checked the condition of your accelerator cable? If not, I would do a visual check for degradation, and possibly adjust it (or check the current state of adjustment). This can be a culprit.
• How long ago did you replace your neutral safety switch? What brand did you use (MB or aftermarket/OEM)? I have not been happy with the quality of the replacement NSSs over the past couple of years, so I am just wondering out loud if you could have a faulty one.
• Have you checked the condition (physical) of the wheel sensors and their cables?

Thanks Gerry,
When ASR came on it was always at start up. I could always clear the codes and that would last for a while. Since the new NCC (done two weeks ago, oem part from Autohaus AZ) light has come on at start up and while driving and ASR no longer goes away after clearing codes. Calibration could be the issue. I didn't do the job because it sounded like doing it on a lift would be better. I sent my guy the calibration instructions so I will confirm with him to see if he used them.
ETA was a rebuild about two years ago from Don Roden in Alabama, he came recommended on this site.
Wheel Sensors and accelerator cable and adjustment have not been checked.
Can the ETA, Wheel sensors and accelerator be tested with STAR?
By the way I realize this is not a SL forum but this is the place I trust to get the answers thanks to you and others.

 

[gsxr]

The ASR warning light does not remain on until codes are cleared. It remains on until you turn the ignition off and back on. Clearing the code will not clear the light, if so this is coincidence.

The NSS absolutely must be adjusted when installed. If the mechanic didn't do this, it has to be done next.

Wheel speed sensors are not indicated by the fault codes you listed above. The STAR diagnostic system (SDS, with HHT-Win) can show live data from the various modules along with the specific 3-digit fault codes on the E-GAS. However, unless the dealer tech knows how to interpret the live data, this may not do much besides lighten your wallet. Precious few dealer techs know anything about early 90's cars.

 

[73eldorado]

Ditto to everything Gerry said above. If the light comes on at startup, before you touch the accelerator pedal, the issue will be related to pin 7 code 2 or 3. Code 30 on pin 6 is a generic / ghost code that always appears with limp mode, just ignore this.

Note that all the possible faults on code 3 are related to ETA internals. First triple-check that the accelerator cable is adjusted properly, as this can cause limp mode on startup. If so, there's a faint possibility the ETA may need to be sent back to Don for a checkup. Swapping in a different E-GAS module wouldn't hurt as a test, along with verifying the module is fully seated in the socket.




View attachment 171453

Thanks Dave, for the info and screen shots.
I did check the seating of the modules first which has worked for me in the past, in fact I added a small amount of weather stripping foam to the inside of the can box lid to apply some slight downward pressure on the modules.
I was hoping the eta was not part of the problem but you could be right. I will contact Don to see what he thinks.

 

[gsxr]

Just to clarify... it's far more likely the issue is either the throttle cable adjustment, or NSS adjustment.

Once those two have been ruled out / verified ok, and if pin 7 code 3 keeps returning after clearing, then the ETA is suspect (or, the E-GAS module itself, which controls the ETA).

 

[73eldorado]

Just to clarify... it's far more likely the issue is either the throttle cable adjustment, or NSS adjustment.

Once those two have been ruled out / verified ok, and if pin 7 code 3 keeps returning after clearing, then the ETA is suspect (or, the E-GAS module itself, which controls the ETA).

Thank you, I will verify both.
I will be away for a few week but will report back when I return.

 

[gerryvz]

If you can't confirm that the NSS was calibrated when installed, I would bet 90% that is your problem. You can do this yourself if you drive the car up on ramps. My best guess is that your tech didn't do this. If they said they DID do it, then I would re-check it yourself.



Please refer to the R&R instructions for the NSS, from the factory service manual (also attached). There is also a bit of information on the alignment at this post:

Switching Neutral Safety Switch | Transmission and Driveline

This neutral safety switch is a truely wear and tear item. Over time, it will act up and needs replacement. Examining the circuitry, I think Mercedes engineers did a bad design by using this part. This little mechanical contact has to handle the current to activate a solenoid which then...

www.500eboard.co

Once you have done (or re-done) this calibration for the NSS, I would take a look at the throttle cable. If it is original, I would STRONGLY consider replacing it out of hand. They get badly degraded from engine heat, mileage and age. I replaced the one on my E500 three years ago, as it was the original one, just out of hand, because it is a critical component.

I've attached some information on the throttle cable for M119 cars with ASR.

 

[73eldorado]

If you can't confirm that the NSS was calibrated when installed, I would bet 90% that is your problem. You can do this yourself if you drive the car up on ramps. My best guess is that your tech didn't do this. If they said they DID do it, then I would re-check it yourself.

View attachment 171532

Please refer to the R&R instructions for the NSS, from the factory service manual (also attached). There is also a bit of information on the alignment at this post:

Switching Neutral Safety Switch | Transmission and Driveline

This neutral safety switch is a truely wear and tear item. Over time, it will act up and needs replacement. Examining the circuitry, I think Mercedes engineers did a bad design by using this part. This little mechanical contact has to handle the current to activate a solenoid which then...

www.500eboard.co

Once you have done (or re-done) this calibration for the NSS, I would take a look at the throttle cable. If it is original, I would STRONGLY consider replacing it out of hand. They get badly degraded from engine heat, mileage and age. I replaced the one on my E500 three years ago, as it was the original one, just out of hand, because it is a critical component.

I've attached some information on the throttle cable for M119 cars with ASR.

Thanks Gerry and Dave for all the tips. I can't wait to get back and sort this out.
James

 

[73eldorado]

Its time to sort out this ASR issue. My tech tells me he calibrated the NSS properly. Before I double check his work I pulled the codes. Pin 6 code 30 is still present as well as pin 7 code 2. What has changed since the new NSS is that pin 7 code 3 is now gone but pin 19 code 6 is now present. I was able to clear all codes except pin 19 code six which will not clear. In addition I no longer hear my ETA cycle when I turn on the ignition. I did a voltage check on the battery and it was low (under 12). I have the battery out of the car and have charged it up to 12.45. I will leave it overnight and see if there is any voltage drop in the morning.
What I would like to know is why am I not able to clear pin 19 code 6 (Idle speed control faulty). I know that a low battery is not helping my cause.
All help is greatly appreciated.
James

 

[gsxr]

Pin 7 code 2 has a lot of possibilities, you need digital codes from SDS / HHT-Win to narrow down the fault. See screenshot in post #3.

Pin 7 code 3 indicates all ETA related faults (5 different possibilities). If gone now, it could be an intermittent fault, not persistent. See screenshot in post #3.

Battery voltage should be 12.6v after sitting overnight, and should be around 13.8-14.2v with the engine running. Under 12v indicates a completely dead battery that likely would not start the engine. 12.45v is only about 75% charged. If your meter is accurate, those numbers seem odd, but are likely unrelated to the fault codes.

Pin 19 code 6 requires the engine to be started after clearing the code. You cannot clear it and then see 1 blink (or, zero blinks) as on the other modules. If this code keeps recurring, something is up with the ETA, E-GAS, or related switches.... these control idle speed.

Are you still getting limp mode (ABS/ASR lights on)? Or is limp mode gone and you now have a different issue?

 

[73eldorado]

The 12.45 volts (multimeter) I mentioned was after charging for about 6 hours but not long enough for a full charge (I didn't want to leave the charger on during the night). I will bring the battery up to full charge start the car and see if the ASR is still on and check codes again. Battery is 6 years old and my be on its way out. I have read that low voltage can cause issues so I would like to start with a good battery.
I will report back after the battery is at full charge.

 

[Alphasud40]

The 12.45 volts (multimeter) I mentioned was after charging for about 6 hours but not long enough for a full charge (I didn't want to leave the charger on during the night). I will bring the battery up to full charge start the car and see if the ASR is still on and check codes again. Battery is 6 years old and my be on its way out. I have read that low voltage can cause issues so I would like to start with a good battery.
I will report back after the battery is at full charge.

Yes a weak or failing battery can cause all kinds of grief. I know they are expensive but not worth the hassle of intermittent issues.

 

[73eldorado]

Update!
Started with the battery, thought it might be on the way out so got it tested with an EXP800 and it came back a good battery just needed a full charge. Charging the battery took longer than I thought using a 6 amp charger. Along with charging the battery I pulled the egas module and cleaned all pins. I then checked the CTP stop and noticed the return spring for the eta was not attached (which I thought was odd). Not sure which one of these three things was the culprit but when I started the car there was no ASR light. I went for a good ride and then checked for codes and all is well so far with no codes present. I plan to use the car as much as I can over the next little while to see if the light returns.
Thanks again to Dave and Gerry for sharing your expertise.

 

[73eldorado]

Update to my Update. After my last post the ASR light started coming back. There wasn't any pattern to it and all I needed to do was turn off the car and wait a few steamboats turn it back on and no light. I was planning a road trip over the summer and didn't feel that comfortable with this situation so I purchased a used egas module off of ebay for a back up. The egas arrived and I cleaned the pins with deoxit and tapped the module into the CAN box and crossed my fingers. I am happy to say the ebay egas module has been a great success, not one instance of ASR to date. I used the car for my road trip and put on 2,500 kilometers one way over two 13 hour days then the same thing coming home. I'm very happy.