93 400E - ASR Light on, limp mode

[kkalish1793]

Hi fellow enthusiasts:

I have a 93 400E that went into limp mode last night while driving.

I used my blink reader and for Pin #7, got codes 3 and 7. I erased the codes, restarted the vehicle, and the ASR light remains on. I checked Pin #7 again and this time only got code 7. I tried erasing and restarting and the ASR light remains on; however, I tried driving the vehicle and it appears to be no longer driving in limp mode.

When the 400E first went into limp mode and I put the vehicle in park, the engine was revving back and forth between 1,000 and roughly 1,300 RPMs and did not stop until I shut off the vehicle.

Here are all of the items I have replaced over the past two months, all MB genuine parts:

• -Upper Wiring Harness
• -Lower Wiring Harness
• -ETA Rebuild (Don Roden from AL)
• -Copper Plugs
• -Wires
• -Both Ignition Coils
• -Caps & Rotors
• -Fuel Pressure Regulator
• -Air Intake Sensor
• -Fuses inside module box
• -Fuses inside fuse box
• -Thermostat
• -Alternator
• -Battery

This one has me
puzzled. Any help will be most greatly appreciated.

Many thanks!
Kris

 

[gsxr]

Check codes on ALL the other modules, in particular pin 6 (ASR). Ignore code #30 if that comes up, it's a ghost code always stored when you experience limp mode.

Code #7 on pin #7 is for a CAN data transmission fault, although you can't tell which system is not communicating without a digital scanner. The high idle is not uncommon with ETA/E-GAS faults, these items also control idle speed, you get high idle when those systems act up. Double check that both nuts on the positive battery terminal are tight, the smaller (10mm) one is for the power feed to the computer modules.

All the codes for fault #3 on pin #7 are for the ETA, but since that's a recent rebuild... there's a faint possibility your E-GAS module may have died. There's no way to test other than swapping in another one. You can use a 140-chassis E-GAS module for testing (they are relatively cheap on eBay) and if that fixes it, then go shopping for the correct 400E-specific module. I'd try this last though.

BTW, welcome to the forum!

 

[kkalish1793]

Check codes on ALL the other modules, in particular pin 6 (ASR). Ignore code #30 if that comes up, it's a ghost code always stored when you experience limp mode.

Code #7 on pin #7 is for a CAN data transmission fault, although you can't tell which system is not communicating without a digital scanner. The high idle is not uncommon with ETA/E-GAS faults, these items also control idle speed, you get high idle when those systems act up. Double check that both nuts on the positive battery terminal are tight, the smaller (10mm) one is for the power feed to the computer modules.

All the codes for fault #3 on pin #7 are for the ETA, but since that's a recent rebuild... there's a faint possibility your E-GAS module may have died. There's no way to test other than swapping in another one. You can use a 140-chassis E-GAS module for testing (they are relatively cheap on eBay) and if that fixes it, then go shopping for the correct 400E-specific module. I'd try this last though.

BTW, welcome to the forum!

Thanks for your time and help!

I found a used egas, made the swap, and now I am getting the same pin #7, 7 blinks and a new error, pin #4, 17 blinks. ASR light remains on and the 400E feels worse at idle. Very puzzled here.

 

[gsxr]

pin #4, 17 blinks is: "No CAN data transmission with EA/CC/ISC [E-GAS] control module (N4/1)".

Based on these 2 codes, it appears your E-GAS module is not communicating CAN data to the LH (fuel injection) module. This assumes you clear both codes, and both codes return quickly. First check the connections on both modules, make sure the pins are all clean, and the sockets they plug into are also clean. And, make sure both modules are FULLY seated - whack them in place hard with your fist. If the module isn't fully seated, weird stuff can happen.

While I'm not 100% certain, if the CAN wiring and connectors are all good, it seems like the E-GAS or LH module could be defective. However, see if you get both codes with both E-GAS modules. There's a small chance your used replacement E-GAS was also defective.

 

[Alphasud40]

Would a failing base module cause similar issues since it’s part of the CAN network and controls the power supply to the other modules? I know they usually fail outright and in my case it wasn’t powering up the other modules. They are also pretty common and cheap to have a spare.

 

[gsxr]

Great question! I don't think a failing BM would cause these specific codes. The BM/GM is a relatively rare failure (as are E-GAS failures) but I generally see different failure modes with the BM.

 

[kkalish1793]

I decided to drop off the 400E at my indy, will keep you all posted.

An interesting observation, I have been running the car for 20 minutes and the thermostat is only at 50 degrees celsius. The thermostat is new.

 

[kkalish1793]

Turned out to be a bad e-gas module after all.

I lucked out that the replacement I found at a junkyard ended up being good and the 400E is back on the streets today!

They ended up using their Star Diagnostics with 38-pin connector to clear all
the faults- does the simple blink code reader only clear certain codes?

Many thanks all!

 

[gsxr]

Turned out to be a bad e-gas module after all.

I lucked out that the replacement I found at a junkyard ended up being good and the 400E is back on the streets today!

I thought you already tried the second/spare module (back in post #3) and that didn't fix the problem?

They ended up using their Star Diagnostics with 38-pin connector to clear all the faults- does the simple blink code reader only clear certain codes?

The blink code reader will clear all codes but you must clear every single code separately, one at a time - very tedious if there are a bunch of codes. SDS communicates digitally and can clear all codes automatically, in much less time.

 

[kkalish1793]

I thought you already tried the second/spare module (back in post #3) and that didn't fix the problem?

The blink code reader will clear all codes but you must clear every single code separately, one at a time - very tedious if there are a bunch of codes. SDS communicates digitally and can clear all codes automatically, in much less time.

I must have missed clearing a code or two when I put the spare module in?

Alphasud has graciously agreed to have a look at the old module so I will be shipping it out to him today.

 

[gsxr]

I must have missed clearing a code or two when I put the spare module in?

Stored codes will not prevent the module from working properly, but codes that are not cleared can send you off chasing undomesticated waterfowl. If the E-GAS was the only problem, swapping in a good module should have cured the issues immediately, regardless of what codes were stored. I'm still a bit confused.

Alphasud has graciously agreed to have a look at the old module so I will be shipping it out to him today.

Sounds good! Note that I'm not aware of any way to test E-GAS modules other than installing them in a car and test driving. (Also - the E-GAS module can only be tested in a car with ASR.)

 

[Alphasud40]

Dave, I was going to see if there were any capacitors that might be shorted/leaking. Figured if I found something I would send it back for him to test and share with the forum.