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Unread 06-20-2013, 01:14 PM   #1
89hotsauce
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I Need Help 97 Jeep Grand Cherokee Laredo Mysterious Electrical Problem I Believe

Everyone,

What I have


I am currently troubled with the mysterious electrical problem that happens in the life time of many Jeeps. I have a 97 Jeep Grand Cherokee Laredo 4.0l 6 cylinder A.K.A (ZJ) with around 162,000 miles on it. The Jeep ZJ is California emissions and has a security feature. The Jeep has never had any major problems except for the one that I am currently being challenged with. The Jeep has been well maintained with regular routine maintenance oil changes, plugs, wires, distributor cap, rotor, and ect, and has always been very reliable. However since I have had it I been dealing with the stalling issue, but did not think nothing of it because I would just wiggle the connection to the ECU, and like a magic trick it would start. Below I will explain the symptoms that I am being face with, and everything I have done trying to fix the problem. Nothing seems to work hopefully someone can shed some light onto my problem, but I have been too many forums, websites, and talked to a lot of mechanically inclined people nothing wants to work for me. This is the first time I have every made a post on a forum though Jeep lovers please do not let me down.


Symptoms of my Jeep (ZJ)


When I first acquired my Jeep like stated above I dealt with the mysterious stalling issue, but thought nothing of it. I would just wiggle the connection to the ECU. As the problem did become worse I changed the spark plugs, wires, distributor cap, rotor, and ignition coil to parts that could generate and hold more electric. This helped my problem a little, but did not eliminate it. I then thought maybe I needed to get more air into the Jeep (ZJ) so I put a cold air intake onto it, and this helped my problem very much for a little while eliminating it completely. However all good things do come to an end eventually especially when the wrong repairs are being made. These repairs were made about three months before my current issue of not starting. The Jeep (ZJ) cranks and cranks and cranks and cranks, but will not start. When this problem first started I figured it was my ECU that was making this problem occur, so I replaced it with a new one that was pre-programmed. By the way my Jeep decided to do this in Wal-Martís parking lot, so that is where I worked on it for a while. After the new ECU did not do the trick I replaced the throttle body IAC, TBS, AND MAP sensors, but that did not work. I then installed a new crankshaft position sensor still just cranking. I finally decided to spend the money and get it towed from Wal-Martís parking lot to my driveway. After I did this I found out that Advance Auto Parts sold me the wrong ECU. My Jeep (ZJ) is California emission and has a security feature, but the ECU they sold me did not. I then bought a new one that was pre-programmed to my vehicles exact vin# and mileage. However this was not the solution to my problem, so I decided to change the crankshaft position sensor again not once but twice this means I changed it three times. I did this because I read somewhere that Advance Auto Parts tends to sell people faulty ones, and because of my OBD2 codes that I obtain but will later discuss. After this did not work I changed my ignition pick up, but that also did not work. I noticed my security was not working, so I changed the BMC thinking that might help, but it did not. When the key is in the ignition turned to the on position my check engine, and gauges light comes on occasionally, but not every time. There is also a clicking noise coming from the inside fuse box, but I know that is the horn relay. I have checked every connection under the hood, and cleaned them all with electrical cleaner multiple times. I also cleaned all the ground connections and tightened them all. I even pulled off all the protective tubing over the wires, and inspected them to the best of my knowledge everything looked good to me. This problem also causes my battery to not be able to hold a charge. The OBD2 codes that I have obtained at one point P0304 Cylinder 4 Misfire Detected, P0320 Ignition/Distributor Engine Speed Input Circuit Malfunction, P0342 Camshaft Position Sensor Circuit Malfunction, and P0351 Ignition Coil A Primary/Secondary Circuit Malfunction. When I obtained these codes I replaced my coil pack even though it was only around three months old with a new one and eliminated P0351. The code P0320 also disappeared and I did nothing, so I am assuming it is because of the other two codes the P0304 and P0342.

Symptoms of P0342

Camshaft Position Sensor Circuit Malfunction

A wire or connector in the circuit could be grounded/shorted/broken.
In what circuit, and how can I detect this because I have visually analyzed connections and seen nothing wrong.
The camshaft position sensor may have failed.
The 97 jeep grand Cherokee does not have a cam instead it has an ignition pick up which I already changed. Brand new.
The PCM may have failed.
The PCM is brand new I just replaced with a pre-programmed one to my vin# and mileage.
There exists an open circuit.
What does this mean I am not sure if explained be direct.
The crankshaft position sensor may have failed.
Doubt this considering I have replaced it with three new ones since the problem first started. I did this because I heard Advance Auto Parts tends to sell faulty ones.




Symptoms of P0304

Cylinder 4 Misfire Detected


Faulty spark plug or wire
Replaced less than three months before the issue
Faulty coil (pack)
Replaced while this problem has been occurring
Faulty oxygen sensor(s)
OBD2 scanned does not tell me this how else would I know if they are bad.
Faulty fuel injector
Do not know how to check
Burned exhaust valve
What is this?
Faulty catalytic converter(s)
Outer shell is shot and starting to deteriorate, but I do not think I need a new one, and I do not think a new one will help my problem.
Running out of fuel
Had over a quarter tank since my Jeep has not been starting. This cannot be the problem.
Poor compression
What does this mean?
Defective computer
The computer is brand new, so this should not be the issue because it is the exact part for my Jeep.

Short Description of my problems


(1) Jeep just cranks with no start.
(2) Has no spark in coil or plugs.
(3) Battery does not hold charge.
(4) Security does not work (light on dash is not blinking neither)
(5) Check Engine and Check Gauges light are on.


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Unread 06-20-2013, 01:18 PM   #2
xcaliber81
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I just skipped all that and went straight to the short lol. I cant be of much help sorry.
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Unread 06-20-2013, 01:37 PM   #3
ZJNewbi3
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You have a 1997 ZJ, which means you have OBD II, so you can take it to an auto parts store and they can scan the truck for free. Might help you out. Check the fuel pump, relays, and fuses. Lastly, I heard MOPAR sensors are the only trusted sensor to work on ZJs. All others have a possibility to not work even when brand new.
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Unread 06-20-2013, 01:54 PM   #4
Uniblurb
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Read through the stall/no-start problems thread by ZeeJay in the link in my sig.

It doesn't matter how many new aftermarket crank sensors you installed and always go with a Mopar CKP. I had the same problem you did with Advance crank sensors, went through 2 new ones, and a Mopar one finally fixed my stall/no-start problems.

Complete the below test on the CKP plug you currently have installed using a multimeter set to the lowest ohm setting. Place the black probe on the middle ground cavity (B), red probe on the far right pin (C) with locking tab up, and any resistance at all and it's bad.

Now this wouldn't explain why your battery isn't holding a charge and believe I'd have both the battery along with the alternator tested. Check to make sure your battery cables aren't corroded back into the wire. Also there's 2 small nuts (7-8mm) on the middle of the alternator and make sure these connections are clean. One of the wires, believe it's green, goes directly to the PCM through the harness and the PCM tells the alternator when to kick on the charging field. Constant communications going through this wire between alternator & PCM. Good luck!
crankshaft-positon-sensor-test-p.-8d-8-fsm.jpg  
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-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
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Unread 06-20-2013, 02:12 PM   #5
rambo3489
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Not going to tell you anything you don't already know. But to me you have some type of electrical problem. Not mechanical, fuel, or air. Something somewhere is shorting out or coming on when it shouldn't be. This is based on the fact that your battery will not hold a charge. Something is draining it. If it is an essential part of the Jeep the ECM will likely not allow a spark. Which will kill it. And now you cant even start it. Maybe some sensor wires near the ECM were intermittently shorting out and have now completely shorted out on ya?

This would make sense. Let's say power wire is coming in contact with a input wire the ECM the ECM then thinks something is either working or not working. (Depends on how the sensor is configured)

Whatever is going on is causing you battery to drain.

Hope this gives you another perspective. Good luck. And fill us in when you find the problem.
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Unread 06-20-2013, 06:00 PM   #6
ClintNewCastle
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On the wiggle the connection to the ECU, You have some loose contacts in the ECU, meaning there are contacts on the board that may have come unsoldered or just loose, I just repaired one a few weeks ago with this problem, it was the 3 wires for the 5 volt supply, put it back in and no more problems.
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Unread 06-20-2013, 07:40 PM   #7
89hotsauce
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Thanks for the replies I will let you know how things turn out after I check them.
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Unread 06-20-2013, 11:24 PM   #8
Badmunky
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Quote:
Originally Posted by ClintNewCastle View Post
On the wiggle the connection to the ECU, You have some loose contacts in the ECU, meaning there are contacts on the board that may have come unsoldered or just loose, I just repaired one a few weeks ago with this problem, it was the 3 wires for the 5 volt supply, put it back in and no more problems.
This.

There is a video on youtube where a guy shows you how to fix it.

Its really easy, and will not take long.
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Unread 06-21-2013, 12:11 AM   #9
Uniblurb
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Original poster (89hotsuace) already said he put a new ECU/PCM in it programmed to his VIN.
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-Stalling ZJ? 12 things to check before replacing a sensor; the Dirty Dozen
-Crankshaft position sensor multimeter test. & video of testing.
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Unread 06-21-2013, 11:10 AM   #10
89hotsauce
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I was wondering if anyone knows how to reset the security because mine is not working in my jeep. I have tried doing the door lock trick, but that doe snot work is their another way.
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Unread 06-21-2013, 11:34 AM   #11
JS97ZJ
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Are you sure that the PCM has the security feature enabled?
All three door locks are able to reset the security system, try all three.
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Unread 06-21-2013, 01:41 PM   #12
89hotsauce
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The PCM that I order is supposed to be pre-programmed to my vehicles exact vin# and mileage, so it should be enabled already. Is their anyway that I would be able to tell if it was not activated. Also if it is not activated would I be able to reset it still or would I have to have a dealership do that for me?
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Unread 06-21-2013, 03:04 PM   #13
JS97ZJ
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I installed a aftermarket alarm so as to real life functioning I'm not experience but I can help with this,

http://www.jeepforum.com/forum/f13/c...alarm-1481550/
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Unread 06-21-2013, 04:25 PM   #14
89hotsauce
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Ok so I checked the 5 volt circuit that go from the TBS, MAP, CAM, AND CRANK sensors. The reading I go while checking their voltage was TBS = 5.05V, MAP = 11.3V, CAM = 0V, CRANK = jumps around not an accurate reading. However when I connect the red prong to the sensor it makes a noise that sounds like it is coming from the throttle body manifold and also the power distributor box. The wire coming from the connection when this happens is red/gray or red/black. I am not sure why it is doing this. I also plugged the ohm reader into the 5volt supply from the PCM and it gave me a volt reading of 40v and a ohm reading of .986.

I know this narrows my search down to what my OBDII reader has been giving me codes of, but I am not sure if the crank position sensor is bad from the jumps in the reading. This is already the third one, so if this is the case I am going with a mopar one this time. I also changed the cam sensor also know as the ignition pick up already should I also get a mopar one of them with the reading I received.

One more thing could I be receiving these readings because my security is not working properly.

Also why as I getting this noise from the crank sensor when testing it sounds as if something is trying to power on.
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Unread 06-21-2013, 05:29 PM   #15
JS97ZJ
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All the 5v references are coming from the same point on the PCM you should have all those variations. Tr disconnecting all of the sensors and plug each back in separately.
P.S. Check for shorts.
11.png  
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