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jeepmopar76, Jeep/Chrysler Triple Master Tech
Category: Jeep
Satisfied Customers: 2144
Experience:  32yr ASE Master Tech, 9yr Chrysler Master Tech, 19 yr Jeep Dealership service including AMC/Eagle
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1999 Jeep Grand cherokee: getting p0340 and p1391 codes.

Customer Question

I have a 1999 Jeep Grand Cherokee 4.7 V8. I'm getting p0340 and p1391 codes. It was running pretty good but would hesitate a bit. I changed out the cam sensor and crank position sensor with Mopar parts, cleaned the terminals with electrical contact cleaner. I cleaned the connection at the ecu checked grounds and battery voltage. I also cleaned out the throttle body. Right now it will start for a second and then will die, runs terrible. I need some help figuring out this problem. My next step was going to be to check continuity from the cam position harness wires to the ecu. I don't know which pins to check . Trying to figure out if I have a bad ecu or wiring or possible cam timing problem
Submitted: 5 years ago.
Category: Jeep
Expert:  jeepmopar76 replied 5 years ago.

Hello and welcome to Just Answer. My name is Denny; now let me see if I can help you with your Jeep question.

Customer: replied 5 years ago.
I have continuity from the camshaft sensor connector to the ecu connector on all three wires. So the wires are good. If I replace the ecu from another 99 with 4.7 do I need to reprogram it? Can it be done with a Solus scanner? I have a mt 2500 right now but my k13 key is messed up. I just upgraded and should be getting it soon.
Expert:  jeepmopar76 replied 5 years ago.

It will never start, unless both grand Cherokee's did not have security; Don't even try one unless they both do not have security.

Customer: replied 5 years ago.
It has the security key light in when you first cycle the ignition. Is there are way to test the ecu? or how do I replace one?
Customer: replied 5 years ago.
I looked on ebay at some rebuilt ecu,s that they code to the vin. They say it is just plug and play. Do you think I have a bad ecu?
Expert:  jeepmopar76 replied 5 years ago.
It is possible if you are getting the p0340 and good wires, after replacing cam sensor. The last thing to test is wire integrity; With the wires unhooked, you need to ground one end, and light a bulb with the other; i have a fog light set up for this test; you can have good continuity with one wire strand, but this will not feed a load. If the wires test ok, with what you have done, the PCM is the next step.
Customer: replied 5 years ago.
I just replaced the computer and still just barley fires up. Got any ideas of what to check next? Also how do I test the new cam sensor that I just bought? Thanks -Ben
Customer: replied 5 years ago.
Relist: Other.
tech opted out
Customer: replied 5 years ago.
I just took the right hand valve cover off and noticed that the target wheel is bent. What is the easiest way to change the cam sprocket / target wheel? Maybe I can bend it back. What kind of gap do I need between the cam sensor and the wheel?