'03 Liberty Neutral Safety Switch

[tlspear]

I'm new to this forum but am on the Chrysler minivan forum. I love the wealth of information from past posts and member input.I am a good parts-changer, but haven't been formally trained. I have a basic scanner (I am looking to upgrade) and a good knowledge of most automotive systems.


My mom's '03 Liberty 3.7L with 165K, auto transmission, 2WD, quit while she was driving, luckily at a low speed. I had it towed back to my house. It kicked out two codes: P725 and P706. With my scanner I couldn't tell if it was a cam shaft or crank shaft sensor. I changed both. No problem; both very easy to change.

The 725 is a whole different animal. From my understanding, that is the neutral safety switch(NSS), which requires removing the pan to replace. It's also expensive. From my research it is a TSY assembly. They all have to be replaced at the same time. From my research, I read the NSS will shut power off to the fuel pump. If you guys could verify if that is the case, I would sure appreciate it.

The engine cranks in park and neutral. It has spark and wants to run with starting fluid. There is no fuel pressure at the schrader valve. I put a fuel pump on about a year ago. It was still under warranty, so I replaced it anyhow. (Thank God for the access panel) The best I could tell there was no voltage coming to the pump. Does anyone know what the pin assignment is for the fuel pump connector? Where and what voltage am I looking for?

As far as the NSS, there are several posts that show how to bypass it. Unfortunately, none were for this year/model. If I do need to replace the nSS, no big deal, but I would like to verify that that is the problem before I go through the work. My thinking is that bypassing the NSS and the fuel pump comes alive, that would confirm that it is the NSS. If not, I have something else to look for, maybe a wiring pr. It's not the fuse or the fuel pump relay. I ran the shifter up and down and wiggled and jiggled, no response. Is there something else I should be looking for?

Thanks in advance,
Lee

 

[GunnerSchenck]

Definitely think you're on the right track. When you mention checking voltage at the fuel pump, that's where I would start as well. But first, just for **** and gigs, check all your fuses. Just pull the connector off the pump and check voltage there, you'd have to have the key on, but would imagine it's probably somewhere in at least the 11.6v area (given that there's 12v at the battery).
I haven't gone through any NSS issues myself, but it likely would shut off power to the fuel pump.
Much like a fuel shutoff switch in other makes. Typically with a Ford style vehicle, you would have a button to press so you could reset the switch, but I don't believe we have that sort of setup.

 

[GunnerSchenck]

P.S. it's nice to hear of another 03 2WD! (buggthumpup)

 

[tlspear]

from what i remember 4 maybe 5 pin connector. in my case no power to the pump.

What else could shut off the fuel pump?

Also I understand there are ground issues on these guy's

 

[tlspear]

5143151AA 42RLE Transmission Solenoid Block Pack For Dodge Chrysler Jeep Dakota


This is what I'm looking at, CAN this shut off the fuel pump?

 

[Billwill]

If the Jeep starts in Park why bother with the Neutral switch?

If the Neutral switch on the early KJs is faulty then the engine will not crank over..nothing to do with the fuel pump.

You can swap over the Fuel pump relay with an identical relay nearby and while you are about it swap over the ASD relay as well.

You can download the 2002 KJ Service Manual here...includes wiring diagrams.

http://www.colorado4wheel.com/manuals/Jeep/KJ/

 

[tlspear]

it doesn't start at all, I read on a old post that the nss can/will shut off the fuel pump. That's what I'm trying verify.

 

[uss2defiant]

if your 03 is an early enough production jeep, it might have the service hatch in the cargo area to access the fuel pump.

 

[tlspear]

I ran a wire from the battery to the fuel pump. Good fuel pressure, still no start it did try to start on starter fluid. What would keep the injectors from opening?

hears what I'm seeing.

No power to the fuel pump
Gas gage on E
Injectors not opening

 

[uss2defiant]

LOST JEEPS • View topic - Question about engine speed sensor P0725

 

[tlspear]

Would a broken or skipped timing chain make since? other than pulling the valve covers how could I rule that out.

While trying to start with starting fluid it was strange, back fired through the THROTTLE BODY.

 

[tlspear]

I was wrong it doesn't have spark. I assumed it did, it acted like it wanted to run while i sprayed stater fluid. It just cranks over I'm not getting any codes.

 

[Billwill]

I was wrong it doesn't have spark. I assumed it did, it acted like it wanted to run while i sprayed stater fluid. It just cranks over I'm not getting any codes.

If you have the SKIS anti theft system installed...the early KJs have an Amber Key Icon on the cluster when ignition is turned ON. Later KJs have a Red LED on the left of the cluster.

If this feature is fitted....the Icon/LED should go out after a few seconds if the PCM is happy with the chipped key's code.

If the Icon/Led flashes constantly...PCM is not happy with code...the engine will fire and run for about 20 seconds then cut out.

If the Icon/Led is ON constantly....PCM has not received acknowledgement from the ASD relay that it...the ASD relay...has energised. Engine cranks but does not fire. I had this problem once.

If you do have SKIS fitted....and there is a problem... get back to me here.

 

[tlspear]

Thinks for the help, the this one has the key icon its off. I found the trick of holding the trip counter for 3 seconds with the key on. All the lights come and gauges worked.

/www.youtube.com/watch?v=CRtm0esWzT8

Is there a way to bypass the ASD so i can rule that out?

 

[GunnerSchenck]

How far did she make it before the Jeep shut off? More than 2 miles?

 

[tlspear]

total no start.

02 Liberty (3.7L) won't start. No power to fuel pump or spark..

Looks like I'M having the same problem

 

[ltd02]

Thinks for the help, the this one has the key icon its off. I found the trick of holding the trip counter for 3 seconds with the key on. All the lights come and gauges worked.

/www.youtube.com/watch?v=CRtm0esWzT8

Is there a way to bypass the ASD so i can rule that out?

There are other relays that are the same as the ASD in the power distribution center under the hood. I think the blower motor relay and there may even be an unused spare next to the ASD. Just swap one of them in and see if it starts.

Here is the diagram:
https://www.moparpartsgiant.com/par...rty/electrical-power-distribution-center.html

 

[Billwill]

total no start.

02 Liberty (3.7L) won't start. No power to fuel pump or spark..

Looks like I'M having the same problem

I presume you are accessing the wiring diagrams from the link that I sent to you at colorodo4wheel.com?

First check the following fuses are good:

Fuse 15 inside cabin
Fuses 16 and 26 under the hood.

Check the Black wire on the fuel pump goes to ground...splice in a temp wire to it and ground it on a good chassis point. The Dark Green/White wire on the pump should have +12 volts on it.

Remove Fuel Pump Relay and jumper the female plugs inside the empty socket....pin 30 jumper to pin 87. Fuel pump should run with ignition ON.

Likewise remove ASD relay and jumper female pin 30 to 87 and see what happens. If any CEL comes on then remove this jumper!

 

[GunnerSchenck]

total no start.

02 Liberty (3.7L) won't start. No power to fuel pump or spark..

Looks like I'M having the same problem

You said before that it died at a low speed and it was taken to your house? As mentioned, try swapping the ASD relay. Have you done so already?