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SL 55, Stalled while driving won't crank, OBD2 can't communicate with computers
Hello,
I would really appreciate any thoughts on diagnosing the following problem for a 2004 SL 55 AMG.
I was driving the vehicle when it suddenly stalled. There was no warning lights on the display but the engine cut out. I put it in park and try to restart and got nothing. The shifter is now stuck in park. I tried two separate diagnostic tools including Carly for Mercedes but I am unable to communicate with any of the computer modules even though there is power in the port. I can insert and turn the key on the ignition. The key fob operates the alarm/doors.
Some items such as the horn does not work even though it was functional beforehand however lock in unlocking turn signals lights wipers everything selse seems to be operational.
I have checked fuses and relays and also cleaned front left and front right same contact points. There was some corrosion there and also in the boot. Cleaning did not seem to have made a difference.
I currently get an ESP display malfunction and the red battery icon. Note that the consumer battery was a bit weak but I had been driven it for several months without any issues. The starter battery is strong and fully functional.
When when curious aspect is that the car has the exact same symptoms even when I completely remove the connections to the engine ECU.
My running assumption at the moment is that the engine ECU is done or the Central gateway module? Does anyone know where the Central gateway is? Does anyone have any other suggestions. Keep in mind that there is no crank I do not hear the fuel pump running and I am unable to communicate with any of the computers. Thank you so much.
Last edited by Brajan Kola; Nov 21, 2020 at 06:57 PM.
Reason: Spelling error
I would really appreciate any thoughts on diagnosing the following problem for a 2004 SL 55 AMG.
I was driving the vehicle when it suddenly stalled. There was no warning lights on the display but the engine cut out. I put it in park and try to restart and got nothing. The shifter is now stuck in park. I tried two separate diagnostic tools including Carly for Mercedes but I am unable to communicate with any of the computer modules even though there is power in the port. I can insert and turn the key on the ignition. The key fob operates the alarm/doors.
Some items such as the horn does not work even though it was functional beforehand however lock in unlocking turn signals lights wipers everything selse seems to be operational.
I have checked fuses and relays and also cleaned front left and front right same contact points. There was some corrosion there and also in the boot. Cleaning did not seem to have made a difference.
I currently get an ESP display malfunction and the red battery icon. Note that the consumer battery was a bit weak but I had been driven it for several months without any issues. The starter battery is strong and fully functional.
When when curious aspect is that the car has the exact same symptoms even when I completely remove the connections to the engine ECU.
My running assumption at the moment is that the engine ECU is done or the Central gateway module? Does anyone know where the Central gateway is? Does anyone have any other suggestions. Keep in mind that there is no crank I do not hear the fuel pump running and I am unable to communicate with any of the computers. Thank you so much.
Thank you so much. I checked all of the front prefuses under the passenger footwell as well as the ones in the trunk. Some minor corrosion but all intact and functional based on a continuity test with voltmeter and visual inspection.
I also opened and cleaned the front left and the front right SAM. No major corrosion. Have not inspected rear SAM behind passenger seat. I believe that is fine.
I also did check the relays in the trunk. Some corrosion Isolation (K75) Relay on the attached image
. Cleaned with no change.
To reiterate, no difference in my symptoms when I fully unplug the engine ECU. I did measure that ECU is getting 14 Volts of constant power supply. I have not tested any of the outgoing signal wires from the ECU but I can see that it is getting power I am also unable to communicate to any of the computer modules even though I have power to the OBD2.
Quick update: I'm beginning to think that it might be the electronic ignition (EIS). Looking at some other forums, it looks like a failure of the EIS could lead to stalling, failure to crank, and inability to move out of park. Apparently the EIS is vital to the CAM BUS B and C communication.
Not sure, but I'm guessing that is also why I can't communicate to any ECMs vis Carly for Mercedes OBD2. I have tried a spare key with no change.
The EIS could certainly account for the stalling. As for the inability to communicate, on an '03 car it is the communication link between the engine and body CANs. On an '04 and later model that role is served by the Central Gateway.
If I'm not mistaken the OBD-II port accesses the CAN through the Central Gateway module located in the passenger footwell behind the kick panel. A faulty module could account for failure to communicate with most of the control modules, but it wouldn't account for failure to communicate with the half dozen modules with which the port has a direct communication link. That includes every module on the engine CAN (engine, ABC, transmission, etc.) and the instrument cluster.
I'd post this issue in the regular R230 forum where more people will see it than they will here. I'd also post over in the Benz World R230 forum.
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Thank you. That is helpful. I have looked on the passenger footwell (after removing plate and Bose subwoofer). All I can see is the black transmission control unit mounted on the right hand side near the door hinges. Any idea where the Central gateway is mounted?
Thank you, i found it and I don't see any obvious signs of corrosion or moisture. However i do see that only one of the plugs is connected, the larger one.
Last edited by Brajan Kola; Nov 22, 2020 at 03:57 PM.
Thank you, i found it and I don't see any obvious signs of corrosion or moisture. However i do see that only one of the plugs is connected, the larger one.
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