2000 Jeep cherokee Bad ECM ? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Cherokee & Comanche Forums > XJ Cherokee Technical Forum > 2000 Jeep cherokee Bad ECM ?

Labor Day Sale!FS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitFS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 05-05-2008, 10:10 AM   #1
bad455
Registered User
 
Join Date: May 2008
Location: Arizona
Posts: 6
2000 Jeep cherokee Bad ECM ?

Hello,

I am new to this forum and getting a 2000 jeep cherokee from my neighbor this evening. She has it a repair shop due to a no start (does turn over ) the repair shop is telling her the ECM computer is shot and it is $1,000 to change it out. When I get the jeep home tonight is there a way to check to see if it really is the ECM ? I do have a odb 2 reader but not sure if that would read a bad ECM. Also I found a few remanufactured ECMS on EBAY reasonable but where is the ECM located on the 2000 cherookes ? yes this is the 1st one I worked on . I always had the older jeeps and never a newer one with computer controlled engine systems . Thank you Bad455

bad455 is offline   Reply With Quote
Unread 05-05-2008, 11:08 AM   #2
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,515
Most repair shops are actually replace the expensive stuff til it runs shops. They aren't interested in diagnosing simple problems.

Get the Jeep home and start with some simple trouble shooting. Battery and starter connections, spark, fuel, etc.

Give more info on the exact symptoms of the problem. It could be as simple as a failed Crank Position Sensor (CPS) which is very common on the 1997-2001 Cherokee and also relatively cheap and easy to replace.

Used ECM's are about $75-100 and refurbished ones are on eBay for about $175. The ECM is located next to the air cleaner box on the drivers side.





The most likely cause of it cranks and cranks but won't start up is the Crankshaft Position Sensor (CPS) located on the transmission bell housing. Often this part is also referred to as the CranKshaft Position Sensor (CKP) CPS/CKP failure is very common. The CPS/CKP can stop working with no warning or symptoms and the engine will not run or the engine may randomly stall for no apparent reason.

Typical Symptoms –
- The engine may randomly stall for no apparent reason.
- Starter cranks and cranks but engine won't start up and run.
- Fuel gauge and voltage gauge may not work or display properly.
- You sometimes will have No Bus on the odometer after 30-60 seconds.
- A failed CPS/CKP may or may not throw a CEL trouble code.
- No spark at the spark plugs.
- Fuel pump should run and prime for 3-5 seconds.

If the engine cranks and does not start, the fuel pump runs, and it will run on starting fluid, suspect a faulty cam sensor.

Begin with basic trouble shooting of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables or connectors and replace as needed. Do the same for the grounding wires from the starter to engine block, and from the battery and engine to the Jeep's frame/body. You must remove, scrape, and clean until shiny, the cable/wire ends, and whatever they bolt to. Jeeps do not tolerate low voltage, bad connections, or poor grounds and the ECM/ECU may behave oddly until you remedy this.

Exchange the fuel pump relay and the ASD relay with one of the other similar ones in the PDC to eliminate the relays as the cause of the no-start. Check the ASD relay fuse.

Confirm that the fuel pump to runs for 3-5 seconds when you turn the ignition key to ON.

Eliminate the NSS as a cause of no start. Wiggle the shift lever at the same time you try to start. Put the transmission in Neutral and do the same. Do the reverse lights come on when the shifter is in Reverse?

Inspect the wires and wire connectors at the O2 sensors on the exhausts pipe. A short circuit from melted insulation or from broken O2 sensor wires can blow a fuse and the ECU/ECM will loose communication. Don’t get tunnel vision and assume the sensor is bad (unless it tests bad with a meter). Damaged wiring or a dirty connector can inhibit the signal from making it to the computer. Inspect/test/clean/repair wiring or connectors as necessary.

If the CPS/CKP is failed sometimes the OBD-II trouble code reader cannot make a connection to the ECU/computer or cannot read Check Engine Light/MIL codes because the CPS/CKP has failed. Disconnect the code reader, disconnect the CPS/CKP wire connector, and reconnect the code reader. If the code reader establishes contact with the ECU and scans, your CPS/CKP is failed and needs to be replaced.

Crank Position Sensors can have intermittent “thermal failure”. This means that the CPS/CKP fails when the engine gets hot, but works again (and will test as “good”) when it cools back down.

Be sure to purchase a good quality replacement CPS, Echlin (NAPA), Wells, SMP, or BWD manufactured in either USA or Mexico will work and are second only to Genuine JEEP Factory parts. I prefer to get JEEP parts for the CPS and TPS repairs. Cheap “Lifetime Warranty” parts from the Fast Food type auto parts stores are proven to be out of specification or failed right out of the box. They also tend to have a short lifespan.

Diagnostic steps to confirm the CPS is the cause of your no-start

1) You should be able to verify a bad cps, by unplugging it, and turning the ignition key to on. If the voltage gauge and/or the fuel gauge now display correctly and/or the No-Bus is gone, replace the CPS.
2) If the CEL does not come on when the key is turned to the RUN position... then the CPS/CKP is bad.
3) Unplugging and reconnecting the CPS sensor where it connect to the main harness near the back of the intake manifold usually resets the ECU and if the jeep fires right up after doing this you can bet that the CPS is faulty and needs to be replaced.

The 2000 and 2001 will have the CPS in the same location on the bell housing, but the wire connector is near the Transfer Case, not as shown in the diagram below. Simply follow the wire from the sensor to the connector.

CPS Testing

Crankshaft Position Sensor Connector (CPS/CKP)



.



TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines

1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (See Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.

TESTING PROCECURE for 1987 – 1990 4.0 L engines

Test # 1 - Get a volt/ohm meter and set it to read 0 - 500 ohms. Unplug the CPS and measure across the CPS connector's A & B leads. Your meter should show a CPS resistance of between 125 – 275 Ohms. . If the CPS is out of that range by much, replace it.

Test # 2 - You'll need a helper for this one. Set the volt/ohm meter to read 0 - 5 AC volts or the closest AC Volts scale your meter has to this range. Measure across the CPS leads for voltage generated as your helper cranks the engine. (The engine can't fire up without the CPS connected but watch for moving parts just the same!) The meter should show .5 - .8 VAC when cranking. (That's between 1/2 and 1 volt AC.) If it's below .5vac, replace it.

.

.
__________________
.

According to the National Shooting Sports Foundation, AR-15 sporting rifles account for nearly 20% of all U.S. firearms sales.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problem; Government is the problem.

Last edited by CJ7-Tim; 06-08-2008 at 07:11 PM..
CJ7-Tim is offline   Reply With Quote
Unread 05-05-2008, 12:04 PM   #3
mhall02
Registered User
2000 XJ Cherokee 
 
Join Date: Oct 2004
Location: Missouri
Posts: 835
Yep, the CPS on my 2000 failed. Cranked and cranked, no prior warnings, but would not actually fire up, luckily it was in my driveway at home. I could't get a code with my inexpensive code reader so I took a chance since these are known to fail...and was right!! $85 at O'Reilly for a Borg Warner CPS, cheaper than a tow and diagnostic I would guess. Maybe try unplugging and pluggin back in the CPS, some say it will then start and you have narrowed it down to the problem, I did not try this, didn't hear about it till later.
__________________
Patriot Blue
2000 Sport 4X4 4.0 inline six, AW-4 Automatic, stock
Original Owner 264,000 miles
mhall02 is offline   Reply With Quote
Unread 05-05-2008, 09:15 PM   #4
bad455
Registered User
 
Join Date: May 2008
Location: Arizona
Posts: 6
Hi'

I got the jeep home and tried to hook up the odb 2 code reader, It seems like it can not read any codes it comes back with error on the lcd screen. I also checked the reader on my dodge and the code reader is fine. I hope I am right in thinking it is the computer that is what the service station also thought was the problem. The jeep will only turn over but not fire up at all I was thinking about getting a remanufactured computer and swap it out any thoughts ? Thanks in advance Bad455
bad455 is offline   Reply With Quote
Unread 05-05-2008, 09:35 PM   #5
Bgeddes
Ridin' with the King
 
Join Date: May 2005
Location: NEPA
Posts: 1,179
Another vote for the CPS.
__________________
'05 KJ CRD and '00 XJ Classic > Stock DDs
'88 Grand Waggy - Bone stock pseudo-barnfind
Bgeddes is offline   Reply With Quote
Unread 05-05-2008, 11:38 PM   #6
crateampscal
Registered User
2005 TJ Wrangler 
 
Join Date: Feb 2008
Location: Petaluma, California
Posts: 741
according to chrysler, they are only suppose to last 8-10 years. i found a place on the internet called ace.(auto computer exchange). they had one listed for my jeep and it was priced at 249.00. when i called she asked me the price i saw and i told her 199.00.(IM A LIAR) She didnt ask twice sent it out within 3 days. when i got it they sent me a return label. it was really easy and it even has a warranty. something to look into.
crateampscal is offline   Reply With Quote
Unread 05-06-2008, 01:18 PM   #7
bad455
Registered User
 
Join Date: May 2008
Location: Arizona
Posts: 6
hI

Since they were so cheap on EBAY I ordered a new CPS $34.00 and a remanufactured ECM for $199.00 I will replace both and see what happens then repost the results. Thanks for the tips. Bad455
bad455 is offline   Reply With Quote
Unread 05-14-2008, 09:55 PM   #8
bad455
Registered User
 
Join Date: May 2008
Location: Arizona
Posts: 6
New ECm still no good

I replaced the ECM in my 2000 jeep cherokee and It still will not start or pull any codes from the car. I bought a new CPS and will replace it tomorrow. It just makes me wonder why even with a new ECM the code reader comes back ERR just like the 1st one Any ideas ? Also where is the CPS on a 2000 4.0 I thought it was on the bellhousing on the drivers side but I can not se it from under the car. I will also try to check the fuses but I doubt I could be that lucky Thank you Bad455

Last edited by bad455; 05-15-2008 at 09:27 AM..
bad455 is offline   Reply With Quote
Unread 05-15-2008, 06:14 AM   #9
x99j
Registered User
 
Join Date: Jan 2005
Location: ohio
Posts: 448
Quote:
Originally Posted by bad455 View Post
I replaced the ECM in my 2000 jeep cherokee and I still will not start or pull any codes from the car. I bought a new CPS and will replace it tomorrow. It just makes me wonder why even with a new ECM the code reader comes back ERR just like the 1st one Any ideas ? Also where is the CPS on a 2000 4.0 I thought it was on the bellhousing on the drivers side but I can not se it from under the car. I will also try to check the fuses but I doubt I could be that lucky Thank you Bad455
next time start with the cheapest part first (cps). also the cps can sometimes bring down the bus (communication between computer and sensors). so a bad cps can sometimes render the obd2 port useless until the cps is fixed! there are also other canidates that can bring down the bus and cause a no start! but the cps is the most likely culprit. mike
__________________
06 kj 3.7l, 6speed manual, np241 command track

91 yj 2.5l, ax-5, np 231 3 inck lift, 31'' mud rovers

12 kk 3.7L, 42rle, mp1522, d-30, 8.25.
x99j is offline   Reply With Quote
Unread 05-15-2008, 10:10 AM   #10
bad455
Registered User
 
Join Date: May 2008
Location: Arizona
Posts: 6
Thank you Guys

You have been very helpful. as soon as I get home tonight I am crossing my fingers and changing the CPS and will let you know. Is the CPS up high on the bell housing left side on the 4.0 ? and the plug is on the right side ? The Chiltons show it low on the bell housing and plug on the left and I think that is wrong. Bad455
bad455 is offline   Reply With Quote
Unread 05-16-2008, 05:36 PM   #11
bad455
Registered User
 
Join Date: May 2008
Location: Arizona
Posts: 6
Hi

I found the CPS on the 2000 jeep but it is all the way up high on the 4.0 motor. Any hints on getting to it sure is pretty tight in there
bad455 is offline   Reply With Quote
Unread 05-16-2008, 05:48 PM   #12
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,515
Quote:
Originally Posted by bad455 View Post
Hi

I found the CPS on the 2000 jeep but it is all the way up high on the 4.0 motor. Any hints on getting to it sure is pretty tight in there
1997-2001 it is at the top of the bell housing and slightly to the drivers side. I gather up all the socket wrench extensions I can find and then put a wobble adapter on the very end. About 2 -2.5 ft long works well. Lay down under the Cherokee and put your ratchet wrench near the transfer case.


DO NOT drop the bolts into the bell housing.
__________________
.

According to the National Shooting Sports Foundation, AR-15 sporting rifles account for nearly 20% of all U.S. firearms sales.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problem; Government is the problem.
CJ7-Tim is offline   Reply With Quote
Unread 05-16-2008, 06:36 PM   #13
nickh007
Registered User
1998 XJ Cherokee 
 
Join Date: Apr 2006
Location: Overland Park, Kansas
Posts: 92
wow, you are really going about this all wrong lol. you really should have brought it home first and diagnosed it before throwing parts at it. also, not all code readers will work with all vehicles, even if they are from the same manufacturer. the only scan tools i trust with chrysler products are the DRBIII and starscan, lucky me i own a jeep and work at a dealer.
__________________
ΜΟΛΩΝ ΛΑΒΕ
nickh007 is offline   Reply With Quote
Unread 06-07-2008, 05:48 PM   #14
Niminium
Registered User
 
Join Date: Jun 2008
Posts: 1
Quote:
Originally Posted by crateampscal View Post
i found a place on the internet called ace.(auto computer exchange). they had one listed for my jeep and it was priced at 249.00. when i called she asked me the price i saw and i told her 199.00.
Got the web address for this company?

I've found some called autoecm.com, ecmtogo.com, etc. They all seem to be owned by some mysterious Canadian companies, all routed through the same Arizona internet provider that covers up the actual company information. (No contacts, or physical address, etc.)

I've had such bad luck with Canadian company scams, (Euro-Pro, Shark...) that I just won't do business with them again.
Niminium is offline   Reply With Quote
Unread 05-25-2010, 04:12 PM   #15
ghira
Registered User
 
Join Date: May 2010
Location: virginia
Posts: 1
I had a ECM problem. The car would run fine then shut down completely in the middle of the road without warning. It was difficult to turn back on. Waited 30 mins then it may turn back on. At first I thought it was the fuel pump. Replaced it then same problem. Thought fuel pump was defective so I replaced another one. $$$.ouch... Then I thought it was crank sensor so I replaced that. Did the same problem. I wanted to go to junk yard to get a ECM because I was 100% it was the computer/electronics. I could not find any and when I put the same ECM/computer back the Jeep 1999 Limited V8 did not shut off on me anymore. It is fine now, no ECM replacement just take ECM out put back in and loosen screws. You should just take out the ECM computer for a day. Put it back and don't tighten the ECM too much it is causing a short circuit somewhere (read it online somewhere). See if that works because Jeep's factory tightens the screws to much causing people to replace the whole thing.
ghira is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.