TerryHoward3

When I turn the key it will turn over but not start. The check engine light is giving code 1 2 4 1 2 5 5 (or at least that's what it blinks). I ordered a PCM from Flagship one and they sent a part that was dirty and the screw (silver part on the inside) was not secure (no bushing) however, I placed it in the car (probably a stupid move) and it did not start. I removed the PCM and the screw was stuck onto the removable part. Needless to say I am sending it back, but I need my jeep running. I need someone to trust to help me with repairing the jeep I love.
I have a 1995 jeep grand Cherokee Laredo 4X4 VIN# 1J4GZ58S8SC767422. Mechanics have added or say they added, spark plugs, ignition coil, distributor cap, distributor rotor, (replace cap, coil, rotor, & module), crank position sensor. They say I need a transmission control solenoid and PCM.
How can I have the old PCM tested now that it is off the car to see if it is the problem?
(in the photo: top picture is the PCM that I removed and the bottom I paid 265.00 for. Boy was I conned)
New Question: Would the CPS cause the fuel pump to not prime? We are not hearing it prime at all.

cruiser54

Going right to the PCM is a huge jump. They rarely fail.

I'd be checking the Crankshaft Position Sensor which throws no code anyway.

Cane

that is 3 different codes (here I'm taking a guess because there is an extra number in there that doesn't make sense to me (the extra 2 before 55)), they're separated by longer pauses between them.

12 is battery disconnected in the last 50 key cycles, which is normal
41 is "Alternator field switch. Switch not operating correctly and check charging system."
55 signifies the end of the procedure.

I'd check connection to the alternator, and if you have never replaced it I would suggest you do that. like it was said above, CPS is a common culprit for the crank-no start and it doesn't always throw a code, so replace also if you have never done it.

Bustedback

So tell me about these mechanics, is this an actual repair shop, or some dude that says he can fix it? I'm guessing the latter. Start with having the battery load tested. Don't tell me it's ok because your head lights come on, have it tested correctly. The battery and charging system are the first places to start, low battery voltage will cause crazy things to happen.

dave1123

Welcome to CF!

Bustedback is right. The battery may have enough power to crank the engine, but lack the additional load capacity to power the rest of the system while cranking. After checking the battery, try replacing the battery cable clamps. The molded lead ends are known for corrosion inside. The smaller of the 2 red wires that come off the battery clamp sends power to the PDC (Power Distribution Center, the fuse/relay box under the hood). A voltmeter connected to this wire should show at least 12 volts while the starter is engaged. A good indication of bad connections at the battery is if they get HOT after cranking the starter.

On the 95 and older jeeps, a code 41 sets when the voltage from the ASD (Auto Shutdown) relay is below 11.75 volts. The ASD relay powers up the ignition and fuel injector circuits.

JMHO, but the original PCM looks better than the one you bought. Seems to me that missing bushing can cause moisture to get into it.

TerryHoward3

My 95 Jeep Grand Cherokee, 4.0, has been in and out of the shop for over a year now. I live in a small town and the nearest Jeep dealership is in Thompson, Ga, 50 miles away. The first time it happened it broke down on the way to work. The engine would turn but not start. It was towed to Greensboro tires and auto. Engine coil, distributor cap and rotor was added 400.00 later. and I drove for a week and the same thing happened again. I asked help from someone who has a jeep exactly like mines and he suggested the crank position sensor. It was added along with new spark plugs. I purchased a new battery, the cables are good, we checked the fuel pump after someone suggested it was the fuel pump. After the crank position sensor was added it drove for about two weeks and is now in my drive way. It has new belts and things that has nothing to do with the fact that it won't start, so I have decided to learn more about the jeep myself and do my own work, as much as possible, after someone suggested I purchase the PCM and it came looking like the picture.

iweb

You need to take the advise of the guys on this forum, they know their stuff!

I bought a 93 Grand Cherokee that would barely run and the guy I bough it from sold it to me because he ran out of money from throwing new parts at it including everything that you bought.

Turned out the distributor was put in wrong and once I got that figured out it was running perfect. I parked it, went to back it up 2 feet and it died and wouldn't start. I did all the grounds and checked all the wires, fuses, relays, etc and got it running. While it was running I wiggled the small black wire on the neg battery post and the motor died. It "looked" good but was broke off in the molded part.

Even if the battery is new and the cables look good check everything out like was suggested. Good luck.

dave1123

Unfortunately, the CPS (crankshaft position sensor) is a critical piece in the system. If the one that was put in was from Autozone or somebody like that, it may be bad already. When replacing electronic sensors on your jeep, I recommend using only Mopar sensors. Their quality is the best there is even though they cost more.

A little tutorial on the CPS. It is a Hall-effect switch that detects moving objects in it's vicinity by a changing magnetic field caused by that object. A Mopar sensor has a paper spacer on it that sets the proper distance when you install it and is ripped off the first time it's started. It reads the flywheel timing notches as they pass by. When you crank the engine, the CPS sends a signal to the PCM (computer) and tells it the flywheel is ACTUALLY turning. The PCM then turns on the ASD (auto shut down) relay and fuel pump relay. The ASD relay powers up the ignition and the fuel injectors. The CPS then tells the PCM engine speed and cylinder position after it starts.

SO, you can see just how critical this sensor is. I hate throwing parts at it trying to fix a problem. It's called "shotgunning" and can get expensive FAST! Having said that, my advise is to replace the CPS with a Mopar one. The last time you did that, it ran for awhile. Put the original PCM back in.

Also, get a Haynes Repair Manual and read the basics of how your jeep works, then it get really deep into it, go to pacificcoastmanuals.com and download a Full Service Manual for your specific year jeep for $7.99+tax. It's 93mb of pdf files and the BEST manual I've ever seen. Basically, it's a copy of the Factory Service Manual the dealers use. It has system explanations, diagnostic procedures, and circuit diagrams for everything on your jeep.

TerryHoward3

Would the CPS cause the fuel pump to not prime at all?

TerryHoward3

i used both. The dealer said they could not do a diagnostic on a 1995. The shop put on the coils and distributors. It ran two weeks and started doing the same thing. The car broke down on the interstate and a male who worked for auto zone, and driving a 1994 jeep said it was the crank position sensor. He said that he put it on, changed the spark plugs, washed the car and tires. The car ran another week and again died on the interstate. The guy has moved out of state and the jeep sits in my yard, new battery dead and one tire going flat. I need it to run. Country girl need a working vehicle.

TerryHoward3

i purMopard the Haynes Repair Manual and will be sure to use Mopar sensor. You are the second person that's given a top rating for using mopar. Thank you for your advice.
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