Dealer put in a new ECM after swearing up and down that was the problem. Got the truck back last night and today the tach drops, the truck dies, and have the same codes: 0341 and 1689. Apparently not the ECM's fault. Any ideas on what is causing this? 0341 is the CMP, 1689 is "No communication b/tw ECM and the fuel injection pump.

The mechanic says he followed the procedures for diagnosing both and they both lead to replacing the ECM. We now know that's not the culprit, since it's replaced and still malfunctioning.

If the CMP is bad, is there any chance it is causing the 1689 code? What else would cause it? Faulty wiring? I assume that was checked before they recommended the ECM swap.

I also checked the Odometer for codes and got the following:

0123 Throtte/Accelerator Position sensor voltage high
1694
1693

To my knowledge, I didn't have the 0123 or the 1694 before the ECM was swapped.

1693 I know is a companion code, 1694 appears to be also - is this correct?

Could all of these be related?

Any insight is greatly appreciated.

Thanks,
Sam

 

Sounds like a wiring problem to me.

 

OUCH! ECM is the last part I would have thrown at that one.. Chasing an intermittant issue can be testing. First thing I would want to do right now is to see how many starts each code had, record them, and clear them. Drive the truck and see what is the first to pop up. Has the cam sensor been replaced? Sure seems they would have tried that first before the big silver fuse (ecm).

 

Yes, CMP was the first code - 1689 comes right behind it and apparently they come in tandem.

I asked them to make sure that it wasn't the CMP and they assured me that they had run all the necessary tests to rule that out. I'm still not sure I agree with them. We'll see what they say - they have it back.

Good news is they are very apologetic and seem to want to get it right.


I have had a total of four 0341/1689 code combinations that I have pulled, and I believe the mechanis said there were 5 more sets when he pulled them the first time he looked at it.

The other codes are apparently new. thinking of just clearing them and seeing if they come back.

I am thinking they will come back and say the CMP needs to be replaced - which is what I told them when I dropped it off the first time.

If anyone else has any thoughts, please chime in, otherwise I will let you know what they come back with on Monday.

Thanks,
Sam

 

The only "logic" I can see in the replacement of the ecm was that if these two codes always set together, and I do mean "always". From a diag standpoint they really have nothing to do with each other that I can think of (unless of course you have a one in a million wiring issue that is somehow combining the two circuits). The 1689 is a communication prob between the ECM and VP44. While most of the testing has you check the wiring, I have replaced a VP to remedy this dtc. While the cam sensor is not a common componant to fail, I have put a few in here and there. Rarely do they come in completely dead which would make the techs job easier, but rather an intermittant cut out, or loss of power. Also, the cam sensor has totally independant circuits (it's 5 volt, sense circuit, and ground are NOT shared with any other sensor) Being the cam sensor hasn't been replaced, I would most likely install that. It will either fix the prob and save you tons of $$$ on excessive diag time, or will take it out of the loop as a problem.

 

they should have replaced the cmp first...