Merc ML320 non-start /pulsing starter???

[Remap.me.uk]

Hi all, Nice board by the way. OK, i'm curious if anyone might have an answer for me. I have a 1999 Merc ML320, and its been fine since i had it, which has been a few months now. Last week i parked it up for a few days and now it won't start, and symtums are that of a flat battery. Starter pulses in and out, but unlike flat battery its turning engine at smae time, but no start. I have replaced batterys, so thats good. I have by-passed solenoid relay and starter winds over lovely and with plenty of power. I can only trace this problem back as far as the ecu, so my question is, ... do i need a replacement ecu?

also, a number of DTC's are stored for misfiring damages etc??

Mark

 

[wobbly]

Try crank sensor, its on the near side rear of the engine.

 

[television]

Crankshaft sensor item 5 in the link, £45 from Bosch or £85 from MB



http://www.detali.ru/cat/oem_mb2.as...GA=722.662&CT=M&cat=19Y&SID=15&SGR=075&SGN=04

 

[BlackC55]

Hi all, Nice board by the way. OK, i'm curious if anyone might have an answer for me. I have a 1999 Merc ML320, and its been fine since i had it, which has been a few months now. Last week i parked it up for a few days and now it won't start, and symtums are that of a flat battery. Starter pulses in and out, but unlike flat battery its turning engine at smae time, but no start. I have replaced batterys, so thats good. I have by-passed solenoid relay and starter winds over lovely and with plenty of power. I can only trace this problem back as far as the ecu, so my question is, ... do i need a replacement ecu?

also, a number of DTC's are stored for misfiring damages etc??

Mark

Doe3s your diagnostic machine read live data such as the rpm?

If it does check to see if you are getting any value when cranking.

If there is no value a crankshaft sensor is probably the problem.

 

[Remap.me.uk]

I will go and try that now. Would this seriously effect the starter motor? I understand it would effect the ignition.

Mark

 

[Dieselman]

I will go and try that now. Would this seriously effect the starter motor? I understand it would effect the ignition.

Mark

It could be causing the engine to fire early so stalling the motor.

 

[Remap.me.uk]

OK, this is just great. I've checked crank sensor on the bench, and signal is stable...but the car is not attempting to crank at all today. Still battery fully charged and load tests ok, starter cranks ok when by-passed. Seems like an immo problem? Strange how today its not even attempting to start. Further to this, my diagnostic x431 will not comms with ecu now?

 

[BlackC55]

Have you checked all the fuses?

Even the ones on the driver side under dash panel on the right?

 

[Remap.me.uk]

All fuses i can find are in enclosure under bonnet, next to ecu. All dash lights come on, but no response from ecu. I have tried using optican to interigate ecu, still no response.

 

[BlackC55]

look for the others in the footwell.

Oh and you might find the cause is an earth strap has come off.

 

[Dieselman]

Sounds like the ECU might be toast.

Don't know about ML320 but other 320 of this era had a problem with the ECU.

I think BBA Reman can mend these.

 

[BlackC55]

Some testers can't read them very well

 

[Dieselman]

Some testers can't read them very well

But he could yesterday, couldn't he?

 

[Remap.me.uk]

I have sent bba email a few days ago, as follows:

Can you confirm this to be ECU fault? And if so, how much for a replacement?


Thanks
Mark Cassidy

​

From: Mark Cassidy [mailto:[email protected]]
Sent: 13 August 2007 10:30
To: '[email protected]'
Subject: Re: Mercedes ML320 1999


Dear Sir,
We have a ML320 petrol with a start problem! It appears as if there is not enough power for starting, but we have checked this and all is fine including starting motor. At solenoid there is 9vdc approx, and clicks in and out at crank position on ignition. Appears to be sync’d with something, first attempt usually pulses starter and solenoid at 2-3hz, second attempt usually 1hz, and so on so forth. I have checked all relays and replaced solenoid relay, and checked ign switch, but I can only trace back to ecu.

It would also appear the pulsed signal the starter is receiving is effecting other systems, ign etc. We have wired to the starter motor directly and assisted the start with aux power, and the vehicle does start on some attempts but with misfires and other DTC’s.

DTC’s
P1570 Fault in DAS engine control module (A61) STORED
P1542 Pedal value sensor (B71) STORED
P0300-b Misfiring Damages TWC FIL-on
P030-3b Misfiring damages TWC Cyl.3 FIL-on
P030-2b Misfiring damages TWC Cyl.2 FIL-on
P0300-b Misfiring damages TWC CURRENT
P030-3b Misfiring damages TWC Cyl.3 CURRENT
P030-2b Misfiring damages TWC Cyl.2 CURRENT
P0130 G3/4 (o2 cat front right) CURRENT
P0135 o2 sensor heater upstream TWC (R22) CURRENT


Kind regards
Mark Cassidy

... so far no response from them. I will check for fuses in foot well now, but there does not seem to be access for anything down there but obd-2 DLC.

Mark

 

[Remap.me.uk]

Yes, ATR was fine from ECU on Launch yesterday, i recorded DTC's listed above. Also today I have tried ATR with Optican, no response from ECU.

 

[BlackC55]

That 1570 is the important one.

DAS is Drive Authorisation System. (immob)

 

[BlackC55]

It does sound more like a dead Engine control unit.

Check the earth straps anyway.

 

[Dieselman]

That 1570 is the important one.

DAS is Drive Authorisation System. (immob)

Yeah, I got that but it says that is stored as opposed to current.

Is that still an issue?

When were the codes last erased?

 

[Remap.me.uk]

i erased them yesterday, but haven't been able to read today. I think we can say its ecu, but I'm curious, does ecu output signal to the solenoid relay for starter motor? If so, some what of a more in depth question, does anyone know what ic's will need swapping to new ecu to run? i.e immo ic?

 

[Dieselman]

Engine ECU does control the starter, that's how it gives the auto-start after initial key turn and stops the starter on firing up.

IIRC. New ECU should come ready to go but will mate to car after iirc 50 starts.