I went to start my jeep this morning and it cranks but will not start. Odometer says "no bus", obdII scanner says "error 1".

So i went inside and did some quick research...."no bus" could be the guage cluster wiring pins or sockets needing cleaning, and a little dialectric grease. So i cleaned them with aerosol contact cleaner, hit the pins with a small file to freshen up the contact between the pin and socket, applied the dia grease, and the truck cranks but will not start. So i do the same to the ECU sockets and pins, still doesnt fix it.

Little more research shows that the CPS could be the culprit of a "no bus" and the motor not starting. So i unplugged the plug, checked them with a Ohm meter as specified on a DIY found oline, the CPS is fine.

Checked every fuse and relay in both fuse box's, still no start.

Engine has compression, is getting air, and has spark....im not sure if the fuel pump is priming, or if fuel is getting to the engine.

Anyone have any idea's?

 

I had that problem once... Try dumping fuel into the throttle body and starting it (be careful and stand back) if it still doesnt start that means fuel is getting to the engine so its not the fuel pump.. What i did to get mine started was just tune it up, it was 70 bucks for new spark lugs, wires, distrubutor cap and rotor. It might be time just to tune it up anyways

 

Its an 01, it is a coil on plug ignition system.

Ill throw some new plugs at it for the hell of it.

I hate having to drop the damn fuel tank. Why couldnt they just put a damn trap door in the trunk floor area?

 

Ahhh i see, but if your getting spark dont throw new ones on unless its about that time anyways haha

 

Any other ideas on what i should be looking at? Is the bus inside the guage cluster?

 

Found more info on CPS trouble shooting. Seems the CPS is at fault. Ill buy a new one tomorrow.

 

bad cps would mean no spark

 

spray starting fluid in the air tube to the throttle body see if it trys to start....

 

i dont think the CPS is entirely bad, ohm meter says infinite across pins B&C, but when its plugged in my guages do not work. if i unplug it, the guages work.

 

Testing of the crank sensor can be inconclusive. When it tests bad, it is bad. But when it tests good, it "might" be good. Therein lies the quandry.

If you unplug it and the gauges work, you have smoking gun proof that the crank sensor is the suspect. When the crank sensor shorts out, it stops all movement along the computer bus, leaving you with the NO BUS message on your dash.

Please do yourself a favor and buy a Mopar unit from a Jeep dealership. There is no lack of threads with issues about aftermarket crank sensors. The extra money you pay for a Mopar unit is worth every penny in reliability and longevity.

 

I'm having a problem with my 2000 xj, cranks and cranks but no spark. Replaced cps with a cheap one, no spark, bought a BWD brand from advanced auto, no spark, checked continuity on all wires relating to the CPS and ASD circuit, everything checked out, tested ASD relay on a buddy's truck, works fine, cleaned all grounds, no spark, took voltage on 4 pin connector to coil rail, I get pin a=.2V B=.2V c= 12v d=.2v, thought it might be coil rail so o replaced the rail, still no spark, stupidly reset the PCM before getting any codes that might relate to my prob. The my next step is to buy a new PCM Thought I'd get some ideas before I spend the big bucks, any thoughts?!?!?!

 

Im buying a CPS from napa, i have buddies that work there.

 

camshaft sensor? i had that problem too (without "no bus" light) replaced the sensor and fired up.

 

Hhhmmm. I was under the impression the cam sensor gave signal to the fuel injectors. I can smell fuel after I turn the engine over so I assumed the injectors were working. So I ruled out the cam sensor. Also tore the sensor apart cleaned up th magnets and seen that it was turning with the engine. Is there anyway to test it?

 

I'm not sure. When I took mine out the magnet was broke off. So I just went and got a new one. But I get your method of madness.