2005 Jeep Grand Cherokee Fuel Pump Diagram
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Discussion Starter · #1 ·
New Battery. New Fuel Pump. Replaced ICM (integrated control module).
Jeep turns over with plenty of power but does not start. Fuses and relays good. Cannot hear the fuel pump come on. Any thoughts?
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something not connected, or some other problem that can be sorted out with a test light I'd guess.
the list is probably something like:
ASD Relay (PDC)
fuse 6 (PDC)
fuse 24 (PDC)
fuse 24 (junction block, lower dash area)
fuel-pump relay (PDC)
connector at the fuel pump
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Discussion Starter · #3 ·
w1pf said:
something not connected, or some other problem that can be sorted out with a test light I'd guess.
the list is probably something like:
ASD Relay (PDC)
fuse 6 (PDC)
fuse 24 (PDC)
fuse 24 (junction block, lower dash area)
fuel-pump relay (PDC)
connector at the fuel pump
Thanks for the feedback. So the replacement ICM was probably unnecessary as the problem is likely with the PDC and not the ICM?
I need more time to go through the thing this weekend.
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ICM?
I know of the FCM and the IPM..
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Discussion Starter · #5 ·
w1pf said:
ICM?
I know of the FCM and the IPM..
According to the Haynes repair manual there is the PDC (Power Distribution Center) and the ICM (Integrated Control Module) which is parallel to the PDC (the ICM is closer to the battery/front of the vehicle). I was told the two work together for fuse/relay function in this model Jeep. However, the PDC contains the actual fuses and relays for the fuel pump so now I'm unsure why my shop replaced the ICM and not the PDC. Could one adversely effect the other?
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I think what they are calling the ICM is the combination of the IPM and the FCM (the FCM attaches to the battery side of the IPM).
The FCM (through the IPM) applies power to the powertrain control module, which controls the fuel pump relay in the PDC; the output of the fuel pump relay goes through the IPM on its way to the fuel pump. All this assumes it is not a 3.7L, which is wired somewhat differently.
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Did you check to see if there's power at the fuel pump?
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There isn't a blinking red dot on the gauge cluster correct? Top right I believe
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Discussion Starter · #9 ·
Shafer57 said:
There isn't a blinking red dot on the gauge cluster correct? Top right I believe
No, don't think so. What would that mean though?
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Discussion Starter · #10 ·
w1pf said:
I think what they are calling the ICM is the combination of the IPM and the FCM (the FCM attaches to the battery side of the IPM).
The FCM (through the IPM) applies power to the powertrain control module, which controls the fuel pump relay in the PDC; the output of the fuel pump relay goes through the IPM on its way to the fuel pump. All this assumes it is not a 3.7L, which is wired somewhat differently.
My mechanic told me they have spent hours going down the diagnostic tree, from one thing to the next supposedly checking all the basics like crank sensor and rubbing wires, etc., and the ICM isn't giving the signal to the fuel pump via the PDC. The PDC contains the relay and fuse, but supposedly isn't getting a signal (voltage?) through the ICM (ultimately when you turn the key to on).
They now put a new ICM in, swapping out the one they got from the junkyard, to see if that does it. Does this seem like they are throwing parts at it, or is it just me?
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No, don't think so. What would that mean though?
A blinking red dot would indicate a mis-communication between the immobiliser and the PCM. Therefore not allowing it to power the fuel pump, because it thinks it's being stolen. OR it simply is stating that your key for some reason is no longer programmed.
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Discussion Starter · #12 ·
Shafer57 said:
A blinking red dot would indicate a mis-communication between the immobiliser and the PCM. Therefore not allowing it to power the fuel pump, because it thinks it's being stolen. OR it simply is stating that your key for some reason is no longer programmed.
Thanks. My keyless entry has been on the fritz lately, sometimes working and sometimes not working to the point where I have to unlock manually and set off the alarm or turn the key in the door 2-3 times then take it back out and hit the unlock button again for it to work. Does the immobilizer have anything to do with the PDC or is it separate like in the ignition or somewhere else?
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Thanks. My keyless entry has been on the fritz lately, sometimes working and sometimes not working to the point where I have to unlock manually and set off the alarm or turn the key in the door 2-3 times then take it back out and hit the unlock button again for it to work. Does the immobilizer have anything to do with the PDC or is it separate like in the ignition or somewhere else?
Immobiliser modules can be located in numerous places. As far as the key goes, have you tried replacing the battery in it?
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I think your mechanic has no idea what he's doing, but that's just a gut feel. In particular, the crank sensor has absolutely nothing to do with whether the fuel pump runs when you turn the key.
Immobilizer shouldn't care about the battery in the key.. but I'd replace that straight away anyway to get it off the list. and, you can always use your spare key to eliminate that.
on another note, opening the door with the key should not set off the alarm, AFAIK..
...tom
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w1pf said:
...
on another note, opening the door with the key should not set off the alarm, AFAIK..
...tom
If the alarm is armed opening the door with the key sets off the alarm on my 07. If I remember right my manual only lists hitting the unlock button on the key fob as ways to disarm the alarm.
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I think your mechanic has no idea what he's doing, but that's just a gut feel. In particular, the crank sensor has absolutely nothing to do with whether the fuel pump runs when you turn the key.
Immobilizer shouldn't care about the battery in the key.. but I'd replace that straight away anyway to get it off the list. and, you can always use your spare key to eliminate that.
on another note, opening the door with the key should not set off the alarm, AFAIK..
...tom
You are correct, the transponder in the key is what communicates with the immo. telling the vehicle to start. Which doesn't use any battery power.
The truck has no way of telling the difference between the key opening the door or someone reaching inside after breaking a window and opening it. Most vehicle's will do this.
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Discussion Starter · #17 ·
Thought I would follow up on this to keep everyone informed. After a few months and about $1800 later, the problem was a bad wire.
The Jeep ran for about a month after the second repair replacing the ICM, but then didn't start on my wife at the supermarket. Same exact issues as before (motor turning with no fuel pump coming on). After convincing her to not put a rag down the gas tank, we had to tow it for a third time. Took it to a Jeep dealer this time and they traced one bad wire as the culprit (for those of you who want more detail I will post more specifics later, I'm still going back and forth with the dealer over the phone).
In a nutshell, I forked over some good money and threw parts at this thing all for naught. Wish I had gone to a more reputable shop in the first place. I won't openly bash the shop I went to here in this post, but for those of you in Central Texas please feel free to PM me so I can tell you which shop to avoid.
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same intermittent fuel pump issues
I think what they are calling the ICM is the combination of the IPM and the FCM (the FCM attaches to the battery side of the IPM).
The FCM (through the IPM) applies power to the powertrain control module, which controls the fuel pump relay in the PDC; the output of the fuel pump relay goes through the IPM on its way to the fuel pump. All this assumes it is not a 3.7L, which is wired somewhat differently.
im having the same issue with my 2005 WK 4.7. is there a way to check the FCM to see if its working properly? the fuel pump will not come on when the key is turned. cranks fine, all lights work, no red blinking lights. ive replaced the pump twice, wires look fine.swapped relays with no result.first time it happened (abt 100,000miles on it) i had it towed to my garage, we were abt to push it in when i figured id try to start it and it started. i thought since i had the pump and it had so many miles, id replace it anyway. installed new pump, it started right away and was good for abt a month. again it didnt come on when i tried to start one morning.it was under warranty so i replaced it thinking possibly (hopefully) the pump was bad.put the new pump in and it didnt start. played with it for 2 hrs checking the wires, swapping relays and suddenly it started.worked great for abt 9 months, then same problem. let it sit for a month, was abt to get it towed to a dealer, it starts. i drive it to the dealer and explain my problem. its been working fine since and they cant find anything wrong...i love my jeep but have really lost confidence in her, would the FCM work off and on like that?and not effect anything else?thnx in advance!
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Thought I would follow up on this to keep everyone informed. After a few months and about $1800 later, the problem was a bad wire.
The Jeep ran for about a month after the second repair replacing the ICM, but then didn't start on my wife at the supermarket. Same exact issues as before (motor turning with no fuel pump coming on). After convincing her to not put a rag down the gas tank, we had to tow it for a third time. Took it to a Jeep dealer this time and they traced one bad wire as the culprit (for those of you who want more detail I will post more specifics later, I'm still going back and forth with the dealer over the phone).
In a nutshell, I forked over some good money and threw parts at this thing all for naught. Wish I had gone to a more reputable shop in the first place. I won't openly bash the shop I went to here in this post, but for those of you in Central Texas please feel free to PM me so I can tell you which shop to avoid.
im having the same problem!luckily i replaced the pump twice myself so i saved on labor. finally i gave up and took it to a dealer who couldnt find anything cause it was running fine.luckily they didnt charge me cause they felt bad they couldnt find the problem! now when i replaced the pump the wires looked good to me, do you know which part was bad?i know exactly how you feel as this problem is driving me crazy too!!!
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Discussion Starter · #20 ·
danm2005 said:
im having the same problem!luckily i replaced the pump twice myself so i saved on labor. finally i gave up and took it to a dealer who couldnt find anything cause it was running fine.luckily they didnt charge me cause they felt bad they couldnt find the problem! now when i replaced the pump the wires looked good to me, do you know which part was bad?i know exactly how you feel as this problem is driving me crazy too!!!
Sorry I can't be more helpful, I cannot see exactly which wire was spliced, but here is the exact quote from the repair bill:
"C/S VEHICLE CRANKS BUT WILL NOT START SCAN FOR DTC NO DTC FOUND CHECK ELC SYSTEM FUEL PUMP FEED WIRE IS OPEN TRACE WIRING FOUND FUEL PUMP FEED WIRE OPEN FROM RELAY TO C105 CONNECTER HARD WIRE FUEL PUMP FEED WIRE FROM FUEL PUMP RELAY TO C105 CONNECTER AND RETEST"
I believe that C105 CONNECTER is the main connector to the ICM (integrated control module). Some people call the ICM a PCM but my Haynes manual calls the "computer" that controls the fuel pump relay the ICM. Most car guys will fight you and say that this has a PCM, anyhow it's splitting hairs.
Good luck.
Source: https://www.jeepforum.com/forum/f67/2005-wk-fuel-pump-not-coming-jeep-not-starting-1442532/
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