Jeep died...

[CamTom12]

Hey guys! Well, I'm a new member to the forum but not to cars.

My wife's 02 Liberty Limited Edition 4X2 decided to die the other day on her and I can't figure out what might be wrong...

A while back there was a code that came up about a cam sensor, so I cleared it when I scanned it (autozone) to see if it'd come back... That was about 8 months ago and up until a couple of months ago the CEL stayed off. It went on for about a week while I was out of town and then went off again so I figured it was just the gas cap and waited for it to come on again... Then it came on again last week while I was out of town again (go figure) and stayed on. I'm not sure what the code was either time.

So last week while the light's on my wife says this all happens (If it doesn't make sense to you, I understand. She's not a car person and she was distracted by traffic and her cell-phone while the car died). This is mostly in her words so here it goes:
"I turned the key on and the normal chime noise sounded like it skipped like a scratched CD. I got out of the car and looked around it to see if I could figure it out, realized I didn't have a clue what I was looking at, got back in the car and started it up. It started and ran just fine until I got about 15 miles down the road and then I went to push the gas and it slowed down and the steering got hard and I coasted over to the side of the road. I tried to crank the engine but it wouldn't start."

From there we had the car towed back here (home) because I hate paying dealership (or any shop's) labour rates. But at the same time, we're down to 1 car in the family since my truck is still in the shop with internal issues so this may get towed to the dealership soon if I can't figure it out...

So far I've replaced both the Cam Position and Crank Position Sensors, recharged the battery (which seems to be draining quicker than it should but I doubt is part of the problem. My battery maintainer says the cells are good anyhow. I'll get another one once I get it running again.). I pulled the neg battery cable for a couple of minutes to reset the codes in the computer, then tried to crank again with no luck. Then I pulled a plug, hooked it into it's coil and grounded it and cranked and didn't see any spark.

So it seems I'm not getting any spark. I believe I'm getting fuel because the pulled cylinder smelled like gas.

What would cause the coil-on-plug system to not spark? It appears that all the connections are good from the computer to the coil to the plug...

Any other troubleshooting suggestions?

 

[CamTom12]

Oh, and I tried to read the codes before I pulled the battery cable with both the key on-off 3x and the hold tripmeter key-on method and neither worked. The tripmeter button gave me a cool looking dash diagnostic though...

 

[2003KJ]

One way to verify you are getting fuel (even though it sounds clearly like a no spark deal) is to verify the fuel pump is coming on by listening for it, as well as there should be a valve on the fuel rail that's used for hooking up a pressure gage....if I'm not mistaken and the 3.7 is like a lot of other motors you can just put your finger on that valve (I believe it's a shrader valve) and if fuel squirts out, that rules out a fuel delivery problem.

Have you checked all your grounds? Especially those anywhere near the sensors you have replaced? I know it sounds obvious, and I mean no offense towards it, but sometimes we all over look the obvious (or maybe that's just me more often than others.....)

If you could get your hands on a scanner, i'd be willing to bet there's a code or two that's being thrown.

(welcome) to the site by the way!

 

[CamTom12]

Yeah, it's definately getting fuel. And as far as the sensors, they're just weather-pack connectors, no grounds to speak of.

I don't know that I could even get a code now since I cleared the computer, but I dunno... Something's keeping it from starting and I'm thinking it's something to do with spark.

I did some searches on this site and saw something about ASD or something like that... What's that? Would that be something to look for?

Thanks for the welcome!

 

[2003KJ]

Yeah, it's definately getting fuel. And as far as the sensors, they're just weather-pack connectors, no grounds to speak of.

I don't know that I could even get a code now since I cleared the computer, but I dunno... Something's keeping it from starting and I'm thinking it's something to do with spark.

I did some searches on this site and saw something about ASD or something like that... What's that? Would that be something to look for?

Thanks for the welcome!

Info on the ASD, from the 2002 Factory Service Manual:

AUTO SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT

The 5–pin, 12–volt, Automatic Shutdown (ASD)
relay is located in the Power Distribution Center
(PDC). Refer to label on PDC cover for relay location.

OPERATION
OPERATION - ASD SENSE - PCM INPUT

A 12 volt signal at this input indicates to the PCM
that the ASD has been activated. The relay is used to
connect the oxygen sensor heater elements, oxygen
sensor heater relay, ignition coil and fuel injectors to
12 volt + power supply.
This input is used only to sense that the ASD relay
is energized. If the Powertrain Control Module
(PCM) does not see 12 volts at this input when the
ASD should be activated, it will set a Diagnostic
Trouble Code (DTC).

OPERATION - PCM OUTPUT

The ASD relay supplies battery voltage (12+ volts)
to the fuel injectors and ignition coil(s). With certain
emissions packages it also supplies 12–volts to the
oxygen sensor heating elements and the oxygen sensor
heater relay.
The ground circuit for the coil within the ASD
relay is controlled by the Powertrain Control Module
(PCM). The PCM operates the ASD relay by switching
its ground circuit on and off.
The ASD relay will be shut–down, meaning the
12–volt power supply to the ASD relay will be de-activated
by the PCM if the ignition key is left in the
ON position. This is if the engine has not been running
for approximately 1.8 seconds.

DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS

The following description of operation and
tests apply only to the Automatic Shutdown
(ASD) and fuel pump relays. The terminals on the
bottom of each relay are numbered. Two different
types of relays may be used, (Fig. 2) or (Fig. 3).
† Terminal number 30 is connected to battery voltage.
For both the ASD and fuel pump relays, terminal
30 is connected to battery voltage at all times.
† The PCM grounds the coil side of the relay
through terminal number 85.
† Terminal number 86 supplies voltage to the coil
side of the relay.
† When the PCM de-energizes the ASD and fuel
pump relays, terminal number 87A connects to terminal
30. This is the Off position. In the off position,
voltage is not supplied to the rest of the circuit. Terminal
87A is the center terminal on the relay.
† When the PCM energizes the ASD and fuel
pump relays, terminal 87 connects to terminal 30.
This is the On position. Terminal 87 supplies voltage
to the rest of the circuit.
The following procedure applies to the ASD and
fuel pump relays.
(1) Remove relay from connector before testing.
(2) With the relay removed from the vehicle, use
an ohmmeter to check the resistance between terminals
85 and 86. The resistance should be 75 ohms +/-
5 ohms.
(3) Connect the ohmmeter between terminals 30
and 87A. The ohmmeter should show continuity
between terminals 30 and 87A.
(4) Connect the ohmmeter between terminals 87
and 30. The ohmmeter should not show continuity at
this time.
(5) Connect one end of a jumper wire (16 gauge or
smaller) to relay terminal 85. Connect the other end
of the jumper wire to the ground side of a 12 volt
power source.
(6) Connect one end of another jumper wire (16
gauge or smaller) to the power side of the 12 volt
power source. Do not attach the other end of the
jumper wire to the relay at this time.
WARNING: DO NOT ALLOW OHMMETER TO CONTACT
TERMINALS 85 OR 86 DURING THIS TEST.
DAMAGE TO OHMMETER MAY RESULT.
(7) Attach the other end of the jumper wire to
relay terminal 86. This activates the relay. The ohmmeter
should now show continuity between relay terminals
87 and 30. The ohmmeter should not show
continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continuity
and resistance tests. If the relay passed the tests,
it operates properly. Check the remainder of the ASD
and fuel pump relay circuits. Refer to 8, Wiring Diagrams

 

[CamTom12]

Do you have the FSM on digits? Can you email it to me? I'd like to see the diagrams with that too

 

[2003KJ]

Do you have the FSM on digits? Can you email it to me? I'd like to see the diagrams with that too

PM Sent.

 

[JeepJeepster]

Im pretty interested to see what this is since its not throwing any codes. Check for fuel pressure at the fuel rail. There is alittle valve with a cap on it, push that and see if fuel comes out.

 

[offrovering]

have you tried a scanner? Some better scanners take freeze frame data for each CEL. When I scan with mine I get freeze frame, which may indicate what actually happened.

even if you cleared the codes, they may still be stored with data until a full cycle. worth a shot, specially on a dead vehicle.

good luck, keep up posted

 

[adamkrz]

I'm guessing fuel pump, They seem to die then come to life again only to fail a short time later..

 

[CamTom12]

I'm going to see tomorrow if my buddies at AutoZone will let me take their scanner home...

I'm going to double-check the fuel tomorrow also, because I can see maybe a fuel pump issue, but it's definately not getting a spark

 

[CamTom12]

Ok, so I got a scanner and read for any codes and here's what it gave me:

P1389 - Manufacturer Control Ignition System or Misfire.

Not sure what that specifically affects but I've got another 2 hours to peruse the service manual before I have to be somewhere...

Any ideas?

 

[CamTom12]

turns out P1389 is No ASD Relay Output Voltage At PCM according to Jeep. Looks like I know what to buy now

 

[JeepJeepster]

I was thinking PCM.. At least you didnt spend money on a fuel pump!

Hopefully its just a relay.

 

[offrovering]

turns out P1389 is No ASD Relay Output Voltage At PCM according to Jeep. Looks like I know what to buy now

did you buy the part and try it? hope it worked, let us know

 

[CamTom12]

Can't find the relay at Autozone, I'm going to call the dealership tomorrow

 

[CamTom12]

So I ended up finding the relay at Autozone and replaced it...

...no dice. And the CEL popped back up again. I already turned the scanner back in but I bet $5 that it's the same code because of the way that it popped up while cranking.

So, back to square one.

 

[CamTom12]

Ok, so I've done some more checks...

...does anybody have a good working PCM laying around they want to sell?

 

[CamTom12]

Ok, so it's fixed

Apparentley one of the fuses was blown. Before ya'll laugh at me for all the extra **** I did, I definately checked them twice before. It was wierd, I could only see the break under a SureFire flashlight!

Anyhow, the truck is running again. I'm pretty sure one of the sensors (probably the CMP since it threw the code earlier in the year) shorted out and popped the fuse. So now we've got new CMP and CKP and a new fuse, haha