I have a 94 SL320 that needs a ECU, my problem is finding one with the same part number 129 545 19 32. I see a lot listed to fit 94 SL320 but none have this part number. The ones I do find are new from the dealer priced at $1000.00 and up. Is there a interchange list of some sort for these?
It stumbles at idle and will stall sometimes in gear but runs fine otherwise. Plus when starting it does not begin at around 1200 RPM and then drop to 500 it just starts at low RPM. I have tried two throttle bodies with the same result. I checked all the other items I can think of that may give me this trouble. I have a good indy that told me that the ECU is probably bad so I figured to try that but this part number is very scarce and seems to be dealer only at the moment, way too expensive. I did find a repair service in Illinois that will repair it.
The Independent shop I use did check with the Star system and I did with my under dash one. The repair shop I chose to send the ECU to says it's most likely likely an idle control circuit failure on that board.
His reply to my question:
We can definitely take a look at that circuit to see what is going on and repair as necessary. Idle circuitry is a pretty common failure we see modules come in for.
That's a very uncommon failure item. Shops are fond of saying "bad ECU" when they're stumped. Pin 7 can not be read from the OBDII port. For about 10 bucks you can build a flash code reader to read pin 7 and the other modules on the 38 pin. I'd want to see a code 2 on pin 7 with my own eyes before I even thought about replacing that control module.
94/95 ECU from C280/C320/S320 work fine to prove it is not a ECU, and you can find those all day long at Pick - Your -Part for $50 or so, and you can even swap out your SL320 Eprom exchange it with the others.
A 96 will work too, but you cannot swap eproms as they started to soldered them in, but 94/95 were still in PLCC socket..
The non 722.6 six-inline ECU's fail at the EGR/Smog Pump(same transistor, and shorts on) Transistor. I have seen about six like this. Having the smog pump on at idle is no big deal, but the EGR on at idle will cause funky idle, or cause the engine to die, but to test this is easy. One unplugs the orange rubbery vacuum line to the EGR coming out of the passenger side of the valve cover. There are two lines coming out, and the other goes to the smog pump air valve.
With this problem you would get a check engine light, but drive around with the EGR disconnected it should have a super smooth idle as no exhaust gases are being mixed with clean intake air.
Coil problem can cause this stumble next to vacuum leak
Ohh, that list is about 98/99 accurate. Unlike Pick Your Part in LA area where the list is like 40% accurate...
Ahh they offer a 30 day exchange for credit(automatically built in to every part), so maybe get the parts right before he comes down. Pick-your part charges extra for a warranty ..
Martin
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