1998 ML320 110,000 miles.

Hello,
The ML320 has been in the garage for about year now and I was gradually replacing all the O2 sensors (we couldn't determine which on was causing a check engine light) and just generally go through it to get it road ready once again. It is an extra vehicle of ours, so no big hurry to get it out on the road.

I should mention that prior to parking it I did replace the CPS after experiencing a stall out or 2 on the road, and the problem was fixed.

Since it had been sitting so long the battery would no longer hold a charge so i decided to grab a new battery yesterday and get this this back up and running (still have one more o2 sensor to replace).

After installing the battery, I started the engine. Fired right up but stalls out after about 2 seconds. Not like a running out of fuel stall, just shuts off. To rule out the fuel pump, relay, and filter, I pulled the relay and ran a wire from terminal 30 to 87 of the relay. Pump comes on and stays on, but engine does the exact same thing. Then I can get it to start and stall 1 or 2 more times without the relay or jumper wire in at all, so it is holding fuel pressure okay also.

I'm thinking it is a DAS problem now. My wife doesn't know where her key is anymore so I can only use the one I have.

Is there anyway to temporarily disable the DAS (like a jumper in the relay) to determine if that may be the problem? It is pre 2000 so the DAS is part of the AAM and that a major expense to say the least.

Thanks..

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Ron D.
-2007 C230-
-1998 ML320-
-1988 300E-

Hi RonD, i have a similar sounding problem, mines a much earlier one though. I'm wondering if its the O2 sensors but has that made any difference to yours? have you managed to sort it yet?

Think where your O2 senors are.

They are "downstream" of everything.

Many O2 sensor "codes" are caused by the O2 sensor getting a mixture it can't handle. This does NOT mean the O2 sensor is bad.

Many times this is bad MAF sensor. MAF failure is VERY common on M112/3.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

I also think this is an AAM problem, very common after replacing a battery. I don't know what to do except get another key. It usually is caused by trying to start the vehicle with a very discharged battery, and the AAM module decides the key is bad. As I understand it, you only have 8 keys total that the AAM can use, so if you haven't gone through all 8 yet you can go to the dealer and get another key.

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Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C

Thanks everyone, and no the problem has not yet been resolved. I have however purchased a CanODB2 scanner and retrieved the following code. A couple of them seem a bit strange. I did manage to find my wives key and the problem was still present.
---------------------------------------------
Diagnostic Trouble Code Information

MIL DTC
P0110 Intake Air Temperature Sensor 1 Circuit

P0100 Mass or Volume Air Flow Circuit

P1600 Unable to find details for this error code.

P0120 Throttle/Pedal Position Sensor A Circuit

P0115 Engine Coolant Temperature Circuit

In the details it shows both the Intake Air Temp and Coolant Temp @ -40F

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Ron D.
-2007 C230-
-1998 ML320-
-1988 300E-

Richard, whats this about the keys? i have a 1973 280ce with the same sounding problem, haven't changed any sensors, just finished replacing the pump,filter and fuel lines and hasn't changed anything. I only have one key for it or would this be a far later idea then a 1973 model?

RonD, just wondering if your problem is the same, have you tried to clamp the return fuel line? if i clamp the return line my runs a treat, just can't work it out!

The ML's have an RF sensor around the ignition switch ring, and the keys have a device in them that responds. The ML has a DAS system "driver authorization system" that, if the wrong key is inserted, ie a copy of a key, the vehicle will start, run for a second or two, then shut off. The AAM, or "all activities module" in his year vehicle allows up to eight keys to be registered into the DAS, or AAM, and after that the entire setup has to be replaced - locks, ignition switch, keys and AAM/DAS, at an enormous cost of around $3500.
As far as I know, earlier vehicles didn't have this system, but for sure eighties and earlier vehicles didn't, so your '73 is ok, no worries.
Others more in the know may be able to tell you if some of the 90's cars used the system.

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Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C

The temperature sensors are probably disconnected, perhaps by a broken common ground. See if you can get a circuit diagram. You will probably find something in common between these two sensors. That common point will most likely be your problem.

RonD,
I've had the exact problem you are experiencing. It is the transponder in the steering column that's acting up. The only way to resolve it is to replace the transponder. If you still have the mickey mouse master key, try that and it should fire up without stalling.

Luckily mine (also a 98 ML) happened when it was still under warranty, dealer had to replace the transponder twice to completely cure the problem.

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98 ML320 (gone but not forgotten)