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Discussion Starter · #1 ·
So Ive had a issue come up. Was driving home from work and Jeep started hesitating really bad and had no power, like it wasnt getting enough fuel or spark was off. Got it back to work and pulled the codes:

551- pwr steering switch
204- #4 control circuit (shorted)
442- EVAP[realted to faulty gas cap I believe]
455- EVAP[ " " " " " " " ]
1494- Leak Detection Pump pressure switch

any ideas? Ive only had the jeep a couple months and havent owned on in the past so any help is greatly appreciated.

BTW its a 01 2.5 5 speed 4x4
 

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Not a for sure but nowadays a bad gas cap affects many types of vehicles. If u have a buddy u could swap ur cap out with that would be a good start before buying one.
 

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Could the 445 be 455? Thats a large leak in the evap. Check the evap caninster beneath the battery. Sometimes they can get eaten away by battery acid.
 

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Just my 2 cents, but many people remove the evap canister because its only need for emmisions. I dont believe anything with that would create a loss in power. I may be wrong but its just a thought. Also I have gone a week without a gas cap before, it had no effect on my Tj.
 

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Could the 445 be 455? Thats a large leak in the evap. Check the evap caninster beneath the battery. Sometimes they can get eaten away by battery acid.
Not sure what year you're talking about but on my 98' the vaccum box is underneath the battery and the evap on the opposite side.
 

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Not sure what year you're talking about but on my 98' the vaccum box is underneath the battery and the evap on the opposite side.
Yep my 98 is the same way and I know 97's and 99's are that way too. And I know a guy that doesn't have the vacuum reservoir (piece under battery tray) and has no codes being thrown.
 

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Best to reset the CEL & see which ones come back but the P0204 is probably the one causing the power loss. I read my code chart this way: P0204 ---- Injector # 4 Control Circuit ----- Injector # 4 or INJ 4 injector bank output driver stage does not respond properly to the control signal.
 

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Okay heres my best guess...


551- pwr steering switch ....... Power steering wouldnt loose power

204- #4 control circuit (shorted) ...... Should fix but a short would either result in the engine turning off or nothing at all, not a loss in power.

442- EVAP[realted to faulty gas cap I believe] 455- EVAP[ " " " " " " " ] ...... Evap isnt even needed so loosing power doesnt seem related.

1494- Leak Detection Pump pressure switch ..... Not sure but I think this is it. The pressure part may have to deal with fuel pressure or something along those lines relating to power.

Just a guess again but thats what I believe...
 

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Discussion Starter · #10 ·
Best to reset the CEL & see which ones come back but the P0204 is probably the one causing the power loss. I read my code chart this way: P0204 ---- Injector # 4 Control Circuit ----- Injector # 4 or INJ 4 injector bank output driver stage does not respond properly to the control signal.
That was where I thought the problem was coming from. Does each INJ have its own control circuit? If so wondering where the sensor would be to get it replaced?
 

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Discussion Starter · #11 ·
Okay heres my best guess...


204- #4 control circuit (shorted) ...... Should fix but a short would either result in the engine turning off or nothing at all, not a loss in power.
This shorting I dont believe would kill engine. Id relate this to something like dropping a plug...just no fire in that cylinder...no power.
 

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If one injector is not firing you lose 25% of your power.

Each injector gets its signal from the PCM (computer). The injector needs constant battery power & the PCM pulses the ground to the injector to control the open time called the pulse width. If it is not getting power or ground signal it won’t fire. Without researching the code you are getting I’m not sure what is happening but a guess would be that the PCM might be sending the ground &/or power signal but the injector is not getting that signal & not opening. That would possibly mean an open in one or both wires to that injector or a bad connection at either the injector or the ground wire at the PCM (all injectors use a common circuit for power supply, splicing off to each one). So start by carefully checking the wiring to that injector.



There is a lot of info in the FSM. Use the link below, if your yr isn’t there pick the closest one, the injector info is the same from yr to yr.

See online read only FSMs here:
Jeep Knowledge Base
You may have to go to the bottom of the page & pick Jeep Resources & online manuals if it directs you to home page rather than the knowledge base.
 

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Discussion Starter · #13 ·
So had time to try and furthur diagnosis the issue today.

Ran the Jeep and pulled the #4 INJ connector and there was no change in how it was running. Proceeded to pulled all the other connectors and each one changed how the engine was running. So Im pretty sure the INJ is shot. Gonna pick up a set of INJs and replace then all while Im in there.

Hoping I got it figured out...
 

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OK but you still should confirm that injector is getting power & a ground signal from the PCM.
 

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It may be your throttle position sensor getting old and not working well. How long has your check engine light been on?
 

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Discussion Starter · #16 ·
CHeck eng light was on when i bought it a couple months ago. went to autozone and had them read the code and if i remember correctly it was the 442 for the fuel cap. no other codes were in there at the time.

a friend of mine mentioned the TPS and said that could be the problem as well. as mentioned before I cant be sure whats wrong bc i do not have a multi-meter to ck any of the electrical components.

its sitting at my job and live to far away to safely bring it home and can not work on it in their lot. im gonna have to suck it up and tow it to a shop.
 

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Discussion Starter · #17 ·
Water in the fuel and a lot of it! Had to bring it ti the shop bc everything seemed to be in order after further diagnosis. Couldn't seem it figure out what was wrong, i figured it had to be the fuel, only thing I couldn't test.
 
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