xjthing

My wife has a 2001 grand cherokee Laredo 4.0 auto. A few years ago the wj kept shutting off randomly. A trip to the dealership found that the computer was forgetting the security keys. The computer was replaced by them. If I don't start her jeep every 3 weeks or so the battery goes dead even with a solar charger on it.
Today I jumped it and drove about 30+ miles with no problems. I even shut it off a few times. Then I went to start it...it started and ran for a few seconds and then shut off. It will start right back up and shut right back off, even if i floor it. The gauges (fuel, battery, temp, and oil pressure) are all dead. I swapped out the fuel pump relay and checked the fuse (all good). I ghetto checked the fuel pump via the valve on the fuel rail. Every thing seems fine. I hate to say it but I'm thinking another computer issue.
Any ideas with the slow battery drain or the 3 second shut off?

tony270

I would start off by making sure that you have the correct and good battery. Are you sure that you have a solor charger or a tender. Some of these devices only maintain the ability for the battery to hold a charge. It dose this by sending a small charge to the lead plates in the battery preventing scale from forming on the plates, this scale is what kills batteries. I would look at electrical issues, like a pinched wire harness or bundle, do a wiggly test, replaced the coil pac just for GP. The gauges out, and the engine cutting out seem to be a short, could be an internal issue with the battery. If it were me first I would make sure that battery is solid, and I would never listen to a tech at a dealership. It is process of elimination, track the electrical trail for the gauges, look at the wier bundle at the fuse box.

xjthing

It has an aftermarket remote starter in it and I know that it has the key bypass. I had security key issues before and they replaced the computer. I'll contact the place that put the remote starter tomorrow and see if it's their fault.
I'll pull the battery and charge it and try the reset and c/t button test when I get up.

The solar panel is hooked directly to the battery terminals. It helps (not much) stretch out the time before the battery dies.

Cleman Simpson

On my 2011 wrangler the owners manual specified a certain fuse which should be pulled to prevent battery drainage if the jeep was going to be parked for more than a week or two. sorry but I do not remember which fuse it was but if you have the manual to your jeep maybe this is a common procedure to your vehicle also.

tony270

Duplicate

tony270

If you don't know how to use a test light and (preferably a digital) multi-meter find someone that does to help you. They will need the electrical schematics in order to follow the circuits to determine where to investigate. If the vehicle is well maintained, no corroded connections at the battery terminals or inside the cables I would start by the following.
a) Bypass the alarm system, some aftermarket systems come with a jumper for that. I've seen these aftermarket systems fail because of a faulty component/s or connection/s.
(There may be an engine shutdown relay that may or may not be associated with the following components)
b) The Generator/Alternator, this can become hot and fail, then cool down and start working again, check the ground and positive connection, take it to a parts store that offers free starting and charging system test and have them test it.
c) Engine starter relay, and the starter and solenoid connections.
d) The ground at the automatic transmisson switch.
e) The ignition key and start switches.
f) The fuel pump and fuel regulator (you should be able to sense by the smell if the engine is getting enough fuel or not (rich/fat or lean).

I can't see in my manual how the instrument cluster could cause the engine to shut down. I would try to figure out why the engine is shutting down, then find out about the dash. To me it sounds like an alarm issue, but I'm just some newbe dude on the net with nothing else to do.

dave1123

Okay, put on your tin-foil cap and listen up! The WJ is the one vehicle I know the most about having owned one for over 100K miles. Most of this information I've going to give you comes from the FSM I downloaded from pacificcoastmanuals.com for $7.99+tax. It's by far the BEST manual I've ever seen for this vehicle and is a pdf copy of the original factory manual given to dealer techs. It's the best bang for the buck there is.

First of all, the dash gauges all get their information from the PCM, not direct from sensors. Full voltage supply is important to the PCM to function. The entire system gets its power from the smaller red wire that comes from the battery cable clamp and goes to the Power Distribution Center (PDC, relay/fuse box under the hood). The larger red wire goes directly to the starter to supply cranking current and that's all it does.

From the looks of your dash, the PCM is not activated. there seems to be enough power to energize the SKIM (Security Key Immobilizer Module) because it's warning lamp is lit saying it doesn't recognize the key as being valid. You can crank it, but the SKIM shuts down the engine within seconds of starting. This is curious because the PCM is alive enough to activate the starting sequence, but not the gauges. Usually if the gauges aren't active, the key does nothing, not even crank it.

Here's a rundown on a normal start sequence. You insert the key and turn it on. All the gauges and warning lights become active and the warning lights go thru a check sequence. If the SKIM recognizes the key, the key warning lamp will go out. Then you crank it. When the PCM gets a signal from the CPS, it energizes the fuel pump and ASD relays. The ASD relay controls power to the ignition and injector circuits. When the engine starts, The PCM senses this and checks with the SKIM. If the key is not valid, the PCM shuts off the fuel pump and ASD relays, resulting in the loss of ignition and injector power and fuel.

The first thing I would do is check all your grounds and make sure you have full system voltage at the PDC. If you don't, all sorts of weird things can happen. Wiggle the red wire at the battery clamp and watch the voltmeter, making sure the voltage is constant. Also check the cable plugs at the PCM. A bad connection there can do the same thing.

Once you get it running properly, we can discuss a parasitic amp draw test to determine why the battery is going dead. You may have an IOD (ignition off draw) fuse in your 2001. My 2000 doesn't have one. This circuit supplies power to the PCM and radio memory. It is suggested you pull this fuse if the vehicle is to be parked for a long period, like a month or more. Some people say 2 weeks.

This is sort of long winded, but I hope it helps.

BTW, I've heard all sorts of horror stories about electrical problems caused by an aftermarket remote starting system, but I won't go there.

tony270

All I know is these electrical issues can cause the all types of issues, bypass the remote starter, stereo amps, alarm, etc. A bad connection or ground can cause this, it is not that complicated, he had the PCM replaced and the issue is still there. I'm looking at the typical schematic in the Haynes Manual (93-04 JGC). I'm not discounting your information, I'm just posting from my experiences, I'm just some old dude with nothing to do trying to help. I need help sometimes too.

xjthing

After messing with it some more, I really believe that it has to do with the factory security key. I tried using the aftermarket remote starter (this has a security key bypass) and that did the same 3 second run and shut off. I'm wondering if it is a wiring issue with the remote starter disabling the whole thing or the bypass module died. I plan on calling the dealership and seeing if the pcm is still under warranty. I'm also going to call the place that installed remote starter to see if they have ideas. I would love to permanently disable the factory security key forever.

dave1123

My point exactly! I'm just an old dude with nothing to do but help also, BUT I have extensive knowledge and information about the WJ at my fingertips, MUCH better info than you've got with the Haynes manual! I'm not saying the PCM is at fault, but the wiring TO it may be.

Also, the remote start system may be a drain on the battery. My WJ has a system installed by the PO and it has 2 10amp fuses that supply it. The first thing I did was pull those. I looked at the unit attempting to remove it, but there are about 20 wires leading into the surrounding harnesses, so I forgot about it!

I've said my piece. Do with it what you want.

Fred/N0AZZ

I would advise to go by Dave's trouble shooting and what the FSM shows.

xjthing

Due to work I haven't had time to dig into it more yet. I will let you know what I find out. My pcm is out of warranty...go figure. When I get to it I'm going remove and fully charge the battery, clean the terminals, and check the wiring in the drivers door jam. I have already had to repair one broken wire for an issue a few years back. Apparently there is a switch on the door lock that tells the security system that you have unlocked the door.

dave1123

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xjthing

I finally got time to look at it. I checked the ecm connections and they are clean and secure. I checked the door wiring and it appears ok. I cleaned the battery terminals/ clamps and put the battery on charge. I checked the remote starter fuses and they are good. Hopefully it is just a silly low battery / voltage issue. I did find a small amount of water leaking from the a pillar on the drivers side. The grounds on the passenger side appear free from corrosion. I tried calling the place that installed the remote starter and I can't get them to answer the phone. Has anyone had any luck with the aftermarket ecm's that come preprogrammed? I heard there was a company in FL that sells them.

xjthing

Un-f***ING believable. After charging the battery, re-seating the ecm connections, and cleaning the battery terminals...it works. I locked the doors, then hooked up the battery, and then unlocked the doors and started it up. I read somewhere that would reset the security system. I don't know if that's true or not. I drove it to the brother in-laws and parked it there. I'm to old to mess it anymore in the cold and dark, so I'll put the dash back together tomorrow. I'm definitely going to stop by advance on the way home and get the battery and alternator checked. I'll save the troubleshooting of the slow drain for another day. Maybe if the wife drove more than 2,000 miles every year I wouldn't have these problems. Thanks again for everyone's help.