Troubleshooting Ingition Module/Coil

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nvrau
C Class
Posts: 31
Joined: Sun 24 Jun, 2012 10:22 pm
Model you own: w168

Troubleshooting Ingition Module/Coil

Post by nvrau » Tue 26 Aug, 2014 8:22 am

My W168 is missing on cylinder #2. I'm looking for information on how to troubleshoot the ignition module/coil before I purchase a new one.

I recently replaced the starter using the top replacement technique. After reassembly, cylinder #4 was missing as per ECU code P0304 (I believe). I reattached the module connector to ensure a good connection, cleared the code and then it switched to missing on cylinder #2 with ECU code P0302. I again ensured there was a good connection to the module a couple of more times and each time I start the car is comes up as missing on #2 (P0302).

I replaced all four spark plugs but still code P0302 is coming up.

Can anyone assist with troubleshooting procedure or point me to a resource online with information?

nvrau
C Class
Posts: 31
Joined: Sun 24 Jun, 2012 10:22 pm
Model you own: w168

Re: Troubleshooting Ingition Module/Coil

Post by nvrau » Tue 02 Sep, 2014 1:59 pm

Well, I was able to narrow the issue down to cylinder #2 injector not being triggered by ECU. It is getting the constant 12v+ needed but not the pulsing 12v- like the other injectors are getting.

While the car is running, if I unplug & then plug-in the injector connector onto the injector, the car does run slightly better. This tells me the ECU is seeing the injector is connected.

Unless someone chimes in with a suggestion on what to try next, I guess it will be off to a mechanic for further inspection...

nvrau
C Class
Posts: 31
Joined: Sun 24 Jun, 2012 10:22 pm
Model you own: w168

Re: Troubleshooting Ingition Module/Coil

Post by nvrau » Wed 24 Sep, 2014 10:15 pm

Well, I got it running... and it was in-fact the GRY/BLU wire going from injector 2 to the ECU.

Details of the process can be read on BenzWorld.org.

If you need assistance with your ECU in Australia, give Australian ECU Repair a go. Justin was very helpful!

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