The bulletin says to check the ground wires for the communication network lines which are lines h and l. But I can not find any specifics on where these grounds are for the ecm. How many grounds for the ecm am I suppose to check? The info on the bulletin is very broad and not really helpful at all. It makes it sound as if there are 2. On a ground location diagram I found at least 8 that for ecm?????
For this code, you would have to check all the ground wires for excessive resistance that you have found, and this includes the negative battery post. You just clean and reconnect, you can also test if the ECM has proper ground at the OBD II port, On the OBD port pin 4 or 5 is ECM ground, you can measure that for the ECM just as a guide. From the Bulletin, there are 2 main grounds that they want to be checked. M78 and M14.
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