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Chris, Shop Foreman
Category: Jeep
Satisfied Customers: 3340
Experience:  Jeep Certified Master Tech
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Will not start has a codeP0622 I changed the cam sensor,

Customer Question

Will not start has a codeP0622 I changed the cam sensor, crank sensor, coolant sensor and the fuel pump. I think I put in a bad cam sensor.
JA: Are you certain it's the fuel pressure sensor that's in need of attention? What about the fuel rail? Have you checked it yet? What is the model/year of your Jeep?
Customer: The fuel pump will not pump fuel because something has it shut down.
JA: What year is your Jeep?
Customer: 2003 Jeep liberty Sport 6 cyl
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Fuel pump, cam sensor, crank sensor, coolant sensor.
JA: Anything else you think the mechanic should know?
Customer: It was running fine. Sometimes it would not start but after it cooled down it would start, I drove it home and it has not started again. It will turn over but something has the fuel pump disabled.
Submitted: 11 months ago.
Category: Jeep
Expert:  david craig replied 11 months ago.

Hi Im David, your p0622 is the Engine Control Module (ECM) uses the generator turn on signal circuit to control the generator. A high side driver within the ECM allows the ECM to turn the generator ON and OFF. When Generator operation is desired, the ECM sends a 5 volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the Generator is enabled by the ECM, the voltage regulator controls generator output independently of the ECM. Under certain operating conditions, the ECM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit

Customer: replied 11 months ago.
What do I need to do to fix it ?
Expert:  david craig replied 11 months ago.

the very first thing to do with any generator/starter/battery issue is to always pull the battery terminal off, clean them and tighten them down good. Then make sure the alternators large cable is clean of corrosion and tight. The same for the cables to the starter. also make sure the battery negative cable is corrosion free and tight where it connects to the engine block. then we can go from there.

Customer: replied 11 months ago.
You are not too bright. The car is turning over but it will not run. The fuel pump is getting no power.
Expert:  david craig replied 11 months ago.

Excuse me, I can read. Just because the car is turning over and the fuel pump is getting no power, I still want you to check the above mentioned items. But if you dont want to follow my advice and like I said, we will go from there, and keep wasting your money by throwing parts at your car, im sure you'll figure it out. goood day.

Expert:  Amedee replied 11 months ago.

Hello and welcome! Different tech here. Have you checked power going to the fuel pump? If so, what color wire did you check for power?