How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask jeepmopar76 Your Own Question
jeepmopar76
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
16831211
Type Your Jeep Question Here...
jeepmopar76 is online now
A new question is answered every 9 seconds

1999 Jeep Grand cherokee: V8..im 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.

Attachments are only available to registered users.

Register Here

Attachments are only available to registered users.

Register Here

Attachments are only available to registered users.

Register Here
View Full Image

Attachments are only available to registered users.

Register Here

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?