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Dan
Dan, Technician
Category: Jeep
Satisfied Customers: 23706
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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Grand Cherokee: I replaced the ecu on my 2004 jeep because

Customer Question

I replaced the ecu on my 2004 jeep because i was getting misfires and it started good after a few minutes it went back to the same way
Submitted: 1 year ago.
Category: Jeep
Expert:  Dan replied 1 year ago.
Hello, my name is ***** ***** I'm here to help get your problem solved. Is your check engine light on or does it ever come on? Thanks.
Customer: replied 1 year ago.
Yes it is on, i used to get code p0306 and all my injectors misfired but now i only get code p0206 and it stalls
Expert:  Dan replied 1 year ago.
P0206 is related to cylinder 6 injector which most likely means injector has failed. You can check resistance of injector and compare to others or swap with another cylinder to see if misfire follows injector and if so replace. Let me know how it goes or if you have more questions, thanks.
Customer: replied 1 year ago.
The problem here is why is the truck stalling wen i replaced ecm and coil pack already wat other part can it be
Customer: replied 1 year ago.
Your telling me i need to replace injector or check the harness??
Expert:  Dan replied 1 year ago.
The injector problem will cause vehicle to stall. P0206 can only mean injector or wiring so it definitely sounds like the injector is cause of your problem. You can use a LED test light to verify injector connector has good power and ground pulse, if so replace injector. Let me know if you have more questions, thanks.
Customer: replied 1 year ago.
So your saying my ecu didnt habe to be replaced?
Expert:  Dan replied 1 year ago.
That is how it sounds. If you have been getting P0206 since beginning the coil and ECM should not have been replaced.
Customer: replied 1 year ago.
But i was also getting p0306 before replacing ecu
Expert:  Dan replied 1 year ago.
P0206 means cylinder 6 injector problem. P0306 means cylinder 6 misfire. P0206 should always be the first assumed cause of P0306 vs going to other things like coil or ECU.
Customer: replied 1 year ago.
I was also getting p0122 p0300 before replacing ecu
Customer: replied 1 year ago.
Now i only get p0206
Expert:  Dan replied 1 year ago.
If P0206 was problem then injector still would have been best place to start vs replacing coil and ECU. Let me now if you have more questions, thanks.
Customer: replied 1 year ago.
Wat do you suggest i do to fix p0206. Im tired of putting money into this car and still can't move it
Expert:  Dan replied 1 year ago.
I'd verify injector is getting good voltage and ground pulse using a LED test light and if so replace injector. Let me know if you have more questions, thanks.
Customer: replied 1 year ago.
How do i verify if its getting good ground pulse
Expert:  Dan replied 1 year ago.
The LED light will pulsate off/on while trying to start vehicle.
Customer: replied 1 year ago.
Wat type of led light can i use?
Customer: replied 1 year ago.
So.i remove the plug to injector 6?or how does the process to testing it goes thanks
Expert:  Dan replied 1 year ago.
That is correct, remove connector from injector to test. Your local parts store will sell you a LED test light for around $15 or so.
Customer: replied 1 year ago.
Is there a specific name for it?
Expert:  Dan replied 1 year ago.
No, just LED test light. There is a special tool called a "noid light" which they might barrow out to you for free. THis is just a led test light specifically meant to test injectors but a regular led test light will work fine too.
Customer: replied 1 year ago.
So remove connector point light at it while someone cranks it?and wat is suppose to happen to knw if its good or not??
Expert:  Dan replied 1 year ago.
Here is a video that shows how to se the noid light. If light flashes then that proves wiring is good and you need to replace injector.
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https://www.youtube.com/watch?v=5MmR-wXddVw
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Customer: replied 1 year ago.
Does the ecu part number have to be exact on my ecu because all numbers are the same just last letter is different does it matter
Expert:  Dan replied 1 year ago.
No, they do not need to be the same as many are interchangeable.
Customer: replied 1 year ago.
Wen i turnd it on this morning alot of white smoke came on is it because of the code i am getting?
Expert:  Dan replied 1 year ago.
Most likely.
Customer: replied 1 year ago.
I was told. It was burnt oil
Expert:  Dan replied 1 year ago.
Burned oil would be blue.
Customer: replied 1 year ago.
Oh k well i still need to check that injector im in California so last night it was too late to buy a noid light ill get to it today thanks.
Expert:  Dan replied 1 year ago.
No problem, let me know how it goes when you get a chance. Thanks.
Customer: replied 1 year ago.
Noid test light passed wat else can i check
Expert:  Dan replied 1 year ago.
That means you need to replace injector.
Customer: replied 1 year ago.
I disconnected all my wire harness from ecu all the way to injectors since i wasnt getting no reply from you and i saw one cable was pinched so i peeled it and taped it connected all my cables back and turn the truck on ran it for a few miles and it seems to work fine
Expert:  Dan replied 1 year ago.
Good to hear it is running like it should, that is strange noid light was working if wire was pinched. Thanks for update and let me know if you have more questions. Thanks.
Customer: replied 1 year ago.
I Knw it is weird hope ot keeps running good i will keep you updated thanks!
Expert:  Dan replied 1 year ago.
No problem, have a good night! Thanks.