Help 00xj crank no start/no bus

Hey guys I have a 00 Jeep Cherokee xj 4.0l v6. I’m having a no start issue as it is just cranking and no bus on the tach. When plug computer up won’t read anything. Common problem read is crank position sensor bought a new one put it in and still same thing just cranks no start. Cleaned all the grounds on the Jeep still same thing just cranks. Also has new fuel pump to, and I checked all fuses they are good. I’m trying to get this fixed on my own if I can bc money is tight to bring to a shop and get it towed etc. need to get this unit running ASAP if you guys can help me get it going would be appreciated. I don’t want to throw any more parts at it trying to find the actual issue. Thanks

Hey guys it’s me again really need help with this idk what to next.

Hey Apav84! First we need some basic information from you. What kind of test equipment do you have available? Multimeter, test light? What scan tool do you have, specifically?

With the 'NO BUS' message, I believe your next easiest test is to check a 5V reference circuit under the hood. The TPS is right on the throttle body, easy to access once you have the intake tube off.



Unplug the TPS, connect a multimeter to the battery negative post, turn the key on, and measure for voltage at all three pins. Note the wire colors and what voltage you found on each wire. Do not stuff the multimeter probe into the connector pins.

Please take the above readings and report back with your findings. This test is very important in determining your diagnostic direction, so please be clear about your results.

Hey I have a multimeter measured tps first slot brown/yellow line wire 0.13 next slot orange/black line 2.90 then last slot orange solid 3.00 ... i have a bad battery in the truck as of now have a jump box on it Idk if this is affecting reading

Apav84 wrote: i have a bad battery in the truck as of now have a jump box on it Idk if this is affecting reading

That'd depend on the health of the battery and the jump pack. Use the same multimeter to check the battery voltage (post to post) with the jump pack connected and the key on. I'd want to see 11V, preferably above 12V.

Hey I have a multimeter measured tps first slot brown/yellow line wire 0.13 next slot orange/black line 2.90 then last slot orange solid 3.00 ...

Thank you. This is at least part of your problem. The orange wire is the 5V reference wire, and you measured 3V. If this reading was taken with a battery below 11V, charge the battery and take the same measurements again.

If the battery was above 11V when you took this measurement, then you have a 5V reference problem. There are three possible causes:

1.) There's a partial short to ground in a 5V reference sensor or wire.
2.) The PCM has a weak power or ground feed.
3.) The PCM has failed internally.

Your next easiest move is to start disconnecting 5V reference sensors and rechecking to see if the 5V reference circuit comes back up to 5V. Unplug a sensor, turn the key off for five seconds, turn the key back on and recheck. If the 3V reading turns into 5V, you just unplugged the problem.

Do the easy sensors first. Crank sensor, cam sensor, throttle position, MAP. If you don't see a change, go to the harder ones. Vehicle speed and engine oil pressure. I saw that you replaced the crank sensor already - that doesn't matter. Until you find the problem, your new sensor is just as suspect as any other.

This SD quick tips video shows the testing that we want to do:

I’d first make sure all the powers and grounds at the pcm are good. They should be since you got some voltage at the sensors. I’d still verify though before you go chasing your tail. Do you have a wiring diagram?
On your pcm connectors:
A2-12V ignition
A4,A6,A31,A32- ground
A17, B31- 5v supply
A22- 12 battery

Check those and let us know what you have.

If you need any wiring diagrams let me know.

Hey so I got a new battery then went to test map sensor again and while the key was on I moved the map sensor and when I moved the little cluster of wires the relay kicked on and I heard the fuel pump kick on so I think there’s a broke wire in the cluster it’s dark now so I’m gonna pull apart that part of harness tomorrow because i think that’s the issue