2000cherokee1

i just recently bought a 2000 jeep cherokee. my problem is after 15 to 30 seconds no bus come on with the key on or off i replaced the pcm cam sensor and crank sensor. also i cleaned every connector under the dash and passenger side kick panel. i checked the power at the crank sensor and im getting 10 to 11 volts on three wires theres no ground.. wierd..plz help..

rebelbowtie_GCJC

Have you checked the connections behind the cluster? Also does the vehicle run fine?

2000cherokee1

yes ive checked the connection on the cluster and it was clean but i cleaned anyways and put die electric greese on them and no it dont run no power to fuel pump and getting my grounds are hot on the crank and cam sensor

rebelbowtie_GCJC

try disconnecting the crank position sensor and turning the key on, if the "no bus" error goes away then the sensor is bad; so i have read.

Also does it have any stored codes to go with the no bus and no start issue?

2000cherokee1

the scranner wont read it with the no bus on and ive tried to disconnected the crank sensor and still no bus

rebelbowtie_GCJC

Have you tried to disconnect or inspect any other electric sensors such as TPS or MAP, etc?

2000cherokee1

yea and nothing changes

2000cherokee1

ive disconnected just about everything and it still says no bus

rebelbowtie_GCJC

Well this lks like an issue for someone smarter than me haha anywho heres a free bump and hoping you get it sorted out.

2000cherokee1

well thanks anyways..lol i hope i figure it out too

freegdr

Got this...https://www.cherokeeforum.com/f51/fi...cluster-88247/

2000cherokee1

i havent tried that yet but i also heard people still driving with no bus on.. will that not send power to the fuel pump and also on the cps and cam sensor the ground has 10.5 volts and it should be a ground.. and it wont run at all i put gas in the intake and still wont fire up..

2000cherokee1

just an update i unplugged the entire engine harness and transmission harness and i still have no bus..

CCKen

Are you saying you replaced the PCM, Cam Sensor, and Crankshaft sensor?

10 to 11 volts at any sensor is too high.

Try reading the voltage at the TPS, Cam Sensor, and MAP sensor connectors.

Ignition Switch to RUN, without cranking the engine,

Using a digital voltmeter set at 20 VDC,

On the TPS, Cam sensor, and MAP sensor connectors, touch the (+) probe to the pin cavity with the Orange wire (pin 3) and the (-) probe to the bttery negative post.

The Orange wire to the sensors is the 5 volt reference voltage from the PCM (same for the Crank sensor). You should read around 5 volts. If the voltages at these sensors is 10 to 11 volts, I would suspect battery voltage is leaking into the 5 volt supply system through the Clockspring, via the Horn circuit.

If the voltages at the TPS, Cam, and MAP sensors are within the 5 volt range then the problem is isolated to the Crank sensor circuit.

If you do see 10 to 11 volts at the TPS, Cam, and MAP sensors, gain access to the Junction Block in the passenger foot well and remove the Horn Relay, then check the voltages at the sensors again. See JB diagram below.

Do these tests and get back.



Also, check the ground connections at ground G101 for corrosion and security, see pic. The 2000 XJ won't have a coil at this spot but the grounds are there.

2000cherokee1

thank you ccken for the info.. come to find out the two grounds was going to the starter thats why i was getting 10 volts on all three wires on the crank and cam sensor.. by the way it does run now...thank god..but stilll no bus is on..i think its in the connection though..