1993 500E Check Engine Light, Star Results

[albenjoseph]

Hello 500EBoard,

I just purchased a '93 500E today and I'm doing my best to get it running right.
It had a horrible misfire which I fixed by tightening the loose MAF housing and drying up the moist distributor caps. It's now running very smooth!

Unfortunately, the CEL is still on.

Here is my HHT Printout:

LH1:

004 - Air mass sensor with hot wire B2/2 Volt. too large/small

EZ1:

Control unit does not answer

EFP, TPM, ISC:

No contact with control unit

ASR:

030 - CAN: no reception from EFP N4/1

If anyone can point me to the right direction in solving these issues, I would greatly appreciate it!

Thank you,
AJ

 

[jhodg5ck]

Sounds like you might have an Egas issue there...when they get flakey I see them make a mess of the CAN bus.

Best and most reliable way I have found to test is with a known good from another car. Alt, you can send yours to Beckman for testing and rebuilding..but the reman process is Pricey.

Do you have any 500E/E420 w/ ASR friends around? Does your repair shop deal with these cars much?

jono

 

[gsxr]

Are you using a Mercedes HHT or SDS (HHT-Win) as your digital scanner? If you are using anything like Carsoft... that doesn't work at all.

I find it very odd that there is no response from either the EZL or the E-GAS module, yet the car still runs. Sounds to me like something is up with either your 38-pin diagnostic port, or the multiplexer on the scanner, and the scanner is not reading accurately from either of them. You are also missing the DM codes.

If the E-GAS module was dead or not talking to other systems, you'd get limp mode with the ASR light on in addition to the CEL. If the car is running & driving OK but you only have the CEL, the E-GAS is fine. The CEL only shows emissions-related codes which are stored in the DM. You need to check codes on the DM specifically (also possible with the built-in LED & button in front of the CAN box).

 

[jhodg5ck]

Well, I have bad Egas modules that ONLY cause a CEL but otherwise work fine, some that cause an abnormally high idle.

EZL no response I see All the time, likely means nothing..it had a Moment.

I'm Assuming that ALL of your wiring is in order, from upper to lower harness and actuator. If any of those haven't been done I Always start there.

Jono

 

[gsxr]

Well, I have bad Egas modules that ONLY cause a CEL but otherwise work fine, some that cause an abnormally high idle.

That is weird - I've not seen that before. What code is shown on the DM in this scenario? If the CEL is on, there should be at least one DM code, no?

EZL no response I see All the time, likely means nothing..it had a Moment.

Now THAT is really strange. If it was a one-time fluke I'd ignore it. But if the car runs fine and the scanner won't talk to it... I'd look hard at the 38-pin sockets... might be some corrosion on #17.

 

[jhodg5ck]

I have one that didn't throw a CEL but the car would idle @ 900 ish all the damn time. That was a fun one to find. Couldn't begin to tell you other codes and things sadly...prolly 2 years ago I fought through that?


Re: EZL, that's just it...if it didn't talk the car wouldn't run...I see it on 129's, 140's..124's. One time ya plug in, got nothing...re-run the test..comes back. So, I just ignore it. It's like a bad crank trigger code

 

[albenjoseph]

Yes I have a buddy with a E420 I'll try his! How do I remove the E-GAS?

 

[albenjoseph]

Are you using a Mercedes HHT or SDS (HHT-Win) as your digital scanner? If you are using anything like Carsoft... that doesn't work at all.

I find it very odd that there is no response from either the EZL or the E-GAS module, yet the car still runs. Sounds to me like something is up with either your 38-pin diagnostic port, or the multiplexer on the scanner, and the scanner is not reading accurately from either of them. You are also missing the DM codes.

If the E-GAS module was dead or not talking to other systems, you'd get limp mode with the ASR light on in addition to the CEL. If the car is running & driving OK but you only have the CEL, the E-GAS is fine. The CEL only shows emissions-related codes which are stored in the DM. You need to check codes on the DM specifically (also possible with the built-in LED & button in front of the CAN box).

Hey gsxr,

Im using SDS as my digital scanner. The car idles and revs perfect, it just has CEL. I can't drive it though since it's not registered and has no insurance yet. I noticed that the ASR light goes on ONLY if I move the throttle linkage to rev the engine from the engine bay, not when I press the throttle pedal from inside the cabin.

One of the holes in my diagnostic port is heavily corroded and even cracked, I'm picking up one soon from PICKNPULL and see if it changes anything.
Ill check the codes on the DM after my morning class.

Thank you,
AJ

 

[jhodg5ck]

just make sure it's an ASR car or no dice..;-)

It's on the module box, should say Egas if the sticker is still there!:-D

JOno

 

[gsxr]

Im using SDS as my digital scanner. The car idles and revs perfect, it just has CEL.

OK. Connect the SDS to the DM and see what codes are showing on the DM. (I assume you have a Chinese SDS, btw?)

I noticed that the ASR light goes on ONLY if I move the throttle linkage to rev the engine from the engine bay, not when I press the throttle pedal from inside the cabin.

This is normal. Don't move the throttle linkage in the engine bay to rev the engine, this triggers limp mode, ASR light, and stores an error code.

One of the holes in my diagnostic port is heavily corroded and even cracked, I'm picking up one soon from PICKNPULL and see if it changes anything. Ill check the codes on the DM after my morning class.

Make sure the P+P socket is mint condition, otherwise just buy a new one... they are not expensive. Details are in this thread:
http://www.500eboard.com/forums/showthread.php?t=10073


BTW - I've seen DM failures where the CEL stays on all the time, and the root cause was a defective DM - there was nothing else wrong.

Also, as Jono mentioned above, if you try a different E-GAS module it must be an E-GAS module from an ASR car. Non-ASR cars will have T/LLR modules and these will not work.

 

[albenjoseph]

OK. Connect the SDS to the DM and see what codes are showing on the DM. (I assume you have a Chinese SDS, btw?)



This is normal. Don't move the throttle linkage in the engine bay to rev the engine, this triggers limp mode, ASR light, and stores an error code.



Make sure the P+P socket is mint condition, otherwise just buy a new one... they are not expensive. Details are in this thread:
http://www.500eboard.com/forums/showthread.php?t=10073


BTW - I've seen DM failures where the CEL stays on all the time, and the root cause was a defective DM - there was nothing else wrong.

Also, as Jono mentioned above, if you try a different E-GAS module it must be an E-GAS module from an ASR car. Non-ASR cars will have T/LLR modules and these will not work.

i apologize, but what does DM mean?

 

[gsxr]

DM = Diagnostic Module. This module monitors data from the other modules and when it determines there may be something affecting emissions, it stores the code(s) and will trigger the CEL in most cases. This is ONLY used on USA models. Europe / ROW do not have either a CEL or the DM which controls it.

More info in the first 3 'sticky' threads here:
http://www.500eboard.com/forums/forumdisplay.php?f=23

 

[albenjoseph]

I read the codes on the DM .
I got codes 6 and 17.
Which should mean..
Code 6: Idle speed control faulty
Code 17: Data exchange (CAN) fault between engine control module, ignition control module or electronic accelerator/cruise control module. Bank 1
Correct?

Fortunately, I cleared them and now the CEL is gone! However, I don't know if it'll come back. Let's hope not.
Let me know if I am missing information and need to take other steps to fix the issue correctly.

Thank you,
AJ

 

[albenjoseph]

I can't get DM Code 17 to clear. Anyone have any suggestions on what I should do?

 

[gsxr]

I can't get DM Code 17 to clear. Anyone have any suggestions on what I should do?

DM codes may require driving the car after clearing to make the code go away. If the code comes back after clearing (and/or the CEL turns back on), you'll need to figure out the root cause. Code 17 is generic indicating a communication problem between 2 other modules. You'll have to keep clearing / checking codes on all 6 modules (DM, GM, LH, EZL, ASR, E-GAS) and see which ones are complaining about communication issues. Assuming there are actually codes present on the other modules indicating communication faults, it wouldn't hurt to remove and re-seat all the modules and inspect the connectors while they're out.

 

[albenjoseph]

DM = Diagnostic Module. This module monitors data from the other modules and when it determines there may be something affecting emissions, it stores the code(s) and will trigger the CEL in most cases. This is ONLY used on USA models. Europe / ROW do not have either a CEL or the DM which controls it.

More info in the first 3 'sticky' threads here:
http://www.500eboard.com/forums/forumdisplay.php?f=23

Hey guys, just wanted to update you on my 500E!

The tuner in the trunk was defective, I got a refurbished one at the junkyard and now all is well with my radio!
DM code 17 was caused by the corroded pin #3 IIRC. Another symptom I had was when I would put the ground back on the battery, the fuel pumps would turn on and prime.
Now I'm having misfires when the motor gets warm, my insulator plates are HORRIBLE, they're like chalk and cracked. Going to order new insulator plates and report back.

Thank you again for all of your help, I highly appreciate it!

-AJ

 

[albenjoseph]

Hey guys!

I've got all my codes cleared and car is running mint, thanks to new insulator caps behind the rotor!
However, I can't get my Star DAS with HTT-Win to scan my E-Gas module.
It's saying "No contact with control unit" Pin 7, and I've already replaced the 38-pin connector and corroded pins.
Is my E-Gas just incompatible with Star DAS?

Any help is appreciated.

Thank you,
AJ

 

[gsxr]

It's most likely an issue with your Star multiplexer, or the 38-pin connector. It's unlikely that the E-GAS module would function normally, but not connect to diagnostics. Only way to find out is to connect your Star to a different car with an E-GAS module and see if it works on a different car; and/or swap E-GAS modules on your car and see if the problem remains. If you replaced the 38-pin connector, I'd triple-check to make sure you have the correct wire at pin #7 and also that the wire is properly soldered to the socket.