2001 XJ Won't Start

Hi guys this is the first jeep i've ever owned. Here is some info

2001 Jeep Cherokee Sport
99K miles
Purchased from DC goverment and it did not run, I knew this overall the vehicle seems to be in good shape. They could not get the vechicle to run at their maintenance shop, so they took it to the dealer. Dealer said that the instrument cluster went bad, which in turn made the PCM go bad. Dealer wanted over 2 thousand to fix. They decided to sell it on action, I purchased for $2600 which I think is a good price. When I went to have it picked up I found out that some of the guys at the shope bid on it cause they were going to go to a junkyard and get a used intrument cluster and PCM for under $100 and she be good to go.

This is what i've done so far.

Replaced CPS but still would not turn over, so return CPS.

Pulled instrument cluster cleaned with q-tip and rubbing alcohol and applied dielectric grease, still will not start.

Any suggestions ?

Check your current CPS - there should be a thread on what values to expect around here somewhere.

Also, are you getting spark? If you aren't getting spark it'll point toward an electrical issue like the ECU/PCM or CPS.

Since the shop guys were going to go with the instrument cluster and PCM/ECU, I'd do the same - you got a good price on it, so it shouldn't hurt too bad really and if it turns out you were throwing parts at it, you can keep them as spares or ebay them. Remember you'll have to have the ECU flashed with the new VIN and/or mileage and have the mileage updated in the instrument cluster to make it legal, but it should run as long as you get the same part number out of the same year XJ at the junkyard.

Shot in the dark, also - If you aren't getting spark, check if you get the proper signals at the input of the coil pack/bar, if you do, replace the coil pack, if you don't, the issue lies further back (CPS/ECU etc.)

How do I check if i'm getting a spark? I don't really have tools to check for this

Whoa! Hold your horses. Don't even worry about spark yet. You say it "still would not turn over". That means "will not crank" and "starter motor not turning engine"? If that is truly your condition, you need to address battery, cables, starter, starter relay, ignition switch, before thinking about anything else.

Sorry maybe those where were choice of words, vehicles does crank but it will not start. I'm also getting the "no bus code" which in most case that i've seen here is the CPS.

What exact code number are you getting? Always helps to have the number. Or do you see NO BUS on the dash?

A "no bus" simplified could be a few things. The primary causes that come to mind include a bad computer itself OR it can be one of the 5 volt engine management sensors is shorted and that condition pulls the bus down and stops communication on it.

If it were mine, I would try unplugging each of the sensors one by one and after unplugging each one, see if that fixes the problem. If after trying this with no success on all sensors, it would probably point more towards a fried computer.

My1stJeep said:

Sorry maybe those where were choice of words, vehicles does crank but it will not start. I'm also getting the "no bus code" which in most case that i've seen here is the CPS.

Click to expand...

i thought no bus was the instrument panel connection or pcm problem. the dealership may have been correct and the instrument panel or pcm could be bad and just by cleaning the contacts it didnt solve the problem.

bad cps would give a CEL

Yeah, that usually is CPS (actually CKP), but anyway -- how to check spark. No tools required. You have the coil rail which makes it a little harder. Pull that off the spark plugs. Stick an extra spark plug in the end position and hold the ground end to the head while somebody cranks by turning the key. If you don't have an extra spark plug, you might be able to do it with a nail or some other conducter or pull out one spark plug to use in the test. Be careful as this is high voltage and can kick you on your ass easily. It won't kill you as long as you don't have a pacemaker, but be carefull when it gets turned over.

I'm pretty sure that it's not the CPS, I replaced with a new one and it still did not start just crank. The "no bus" was still on dash. Something else could it be the female connectors for the instrument cluster. I've read that do go bad and that dealer sells new connector that needs be soldered for about $10

If it won't start the engine, I'd bet on it being worse than just the cluster. Usually when that connector goes bad, it'll run and drive normally you just can't tell how fast you're going or anything else on the cluster.

X2 - not running should not be related to the instrument cluster.

My1stJeep said:

Hi guys this is the first jeep i've ever owned. Here is some info

2001 Jeep Cherokee Sport
99K miles
Purchased from DC goverment and it did not run, I knew this overall the vehicle seems to be in good shape. They could not get the vechicle to run at their maintenance shop, so they took it to the dealer. Dealer said that the instrument cluster went bad, which in turn made the PCM go bad. Dealer wanted over 2 thousand to fix. They decided to sell it on action, I purchased for $2600 which I think is a good price. When I went to have it picked up I found out that some of the guys at the shope bid on it cause they were going to go to a junkyard and get a used intrument cluster and PCM for under $100 and she be good to go.

This is what i've done so far.

Replaced CPS but still would not turn over, so return CPS.

Pulled instrument cluster cleaned with q-tip and rubbing alcohol and applied dielectric grease, still will not start.

Any suggestions ?

Click to expand...

2600 for a not running Xj??

What exact code number are you getting? Always helps to have the number. Or do you see NO BUS on the dash?

A "no bus" simplified could be a few things. The primary causes that come to mind include a bad computer itself OR it can be one of the 5 volt engine management sensors is shorted and that condition pulls the bus down and stops communication on it.

If it were mine, I would try unplugging each of the sensors one by one and after unplugging each one, see if that fixes the problem. If after trying this with no success on all sensors, it would probably point more towards a fried computer.


This 5 volt engine management sensors your talking about, is there a diagram as to where they are locked?

Most of the sensors are on 5 volts (5 volts is the native supply voltage for all TTL logic, the ECU and TCU are built using TTL and TTL compatible chips) - at the very least, the TPS and MAP, also possibly the CPS, CTS, and distributor sensor/module.

The CPS is the most likely cause of the no-start and the NoBus. A bad CPS may or may not throw a code. Test the Crank Shaft Position Sensor. In some cases, a failed CPS or more likely a short circuited CPS, has killed the ECU.

Also, look at the wires to the 5v sensors, including the CPS and the O2 sensors. A short in any of these wires will cause a NoBus.

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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.

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

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 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. Jeeps do not tolerate low voltage or poor grounds and the ECM/ECU may behave oddly until you remedy this.



Symptoms –
- Starter cranks and cranks but engine won't start up and run.
- Fuel gauge and voltage gauges 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 CPS/CKP is failed sometimes the OBDII 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.


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


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 displays correctly, replace the CPS.

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.

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. 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 ad with a meter). Damaged wiring or a dirty connector can inhibit the signal from making it to the computer. Check/clean/repair wiring or connectors as necessary.


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.


The 2000 and 2001 will have the CPS in the same location on the bell housing, but the wire connector may be on the passenger side, not as shown in the diagram below. Simply follow the wire from the sensor to the connector.

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I've had a shorted cps that caused a no-bus. I've had a melted o2 heater wire(12v supply from pcm) that has blown the pcm(would crank but not start). As said, unplug every sensor and see if you get the bus back. Check every fuse. Read up about the bad cluster harness that causes no-bus(but don't recall it causing no start). I wish you good luck and hope you don't regret paying $2,600(the price for a higher mileage one in good working condition). I would've paid $500 tops for a broken Jeep with a good shell(which at 99K oughta be).

Hi guys wanted to give you all an updated. On Saturday the 24th my brother in law braught over a friend of his that knows more about vehicles than I do. He checked all the fused, wires, connections, plugs. I was not getting any spark, He suggested calling a friend of his that a computer or code reader to see what the problem is. His friend wanted $65.00 to come over, I said no.

I figured the vechicle has already been taken to a shop where I'm sure they tried everything and were told that it needed a new ECM. I decided to take a chance and go to a local yunkyard and get a used ECM for $25.00 dollars. I took out a ECM from a 2000 Cherokee that had the letters "CC" spray painted on it and a stickers from Darcars of Frederick Maryland. I assumed that this was a "cash for clunkers" vechicle. Installed the used ECM and she fired right up with no problems needless to say I felt relieved and excited.

Thanks to everyone who replied