I'm helping a friend of mine with his 2000 Cherokee that has a no start problem. The engine turns over but won't start. There is a no bus error coming up on odometer and scan tool shows a DTC 1694, which indicates companion module fault. WE have changed the crank position sensor and swapped ECM's. Voltage going to ECM is 12V and feed out is 5V which is correct. Fuel pressure is at 50 PSI and within spec.
We are stumped. Everything I read about camshaft sensor states that it will cause rough running but not a no start. The Jeep just went into this mode at a gas station when shut off for refueling and would not restart.
Any ideas?

 

After clearing the code, it comes right back? Tried unhooking the battery? I am assuming that this is a 4.0l? I do not see a diagnostic flow chart for that code either? P1694 are you sure? ECM will have to programmed to the vin also.

Andy

 

We can't get the code after changing ECM's, with new or old ECM. We did get the no bus in dash though. This is a 4.0L engine with auto.
I spoke with the dealer and was told that the only reason the ECM would need to be reprogrammed with VIN would be for odometer reading, I'm not sure about this?

 

My '01 has an apparatus stuck in the hole on the block where the distributor used to be located on the older engines. It has 2 wires going to it, could this be your problem? Or is this the cam sensor that you have already checked??

Either way, break down the problem and determine if you are lacking spark, fuel or both. Make sure your valve train is still functioning, as I have seen this cause exactly what you are experiencing before.