no bus????

[winterbeater]

1999 Jeep Cherokee 4.0L, Vin S, Eng Cfg L6
Customer Concern: Odometer displays no bus. Crank no start, died while driving.
Tests/Procedures: 1.Test powers and grounds at the Powertrain Control Module (PCM) on the C1 connector. Pins 2 and 22 are power, then check pins 31 and 32 for ground.

2. Next, test the 5 volt power supplies at pin 17 of the C1 connector and pin 31 of the C2, or middle connector, for shorts to ground. Sensors on the circuit are the Camshaft Angle (CMP) sensor, Crankshaft Angle (CKP) sensor, Throttle Position Sensor (TPS), Manifold Absolute Pressure (MAP) sensor and Vehicle Speed Sensor (VSS).

3. Unplug the sensors on the 5 volt power supply, one at a time, while monitoring the 5 volt supply.

4. When the shorted sensor is unplugged, the PCM will wake-up and scan tool communication will return.
Potential Causes: Camshaft Position Sensor (CMP)
Crankshaft Position Sensor (CKP)
MAP Sensor
Oil Pressure Sender
Powertrain Control Module (PCM)
Throttle Position Sensor (TPS)
Vehicle Speed Sensor (VSS)
Wiring Harness

I would test out per wildman's post. Do you have a multimeter? If not, you need one as a companion tool for your XJ.

 

[jneary]

poor connection behind the cluster on the right side connector. replace the connector nd solder the new wiring to the original harness

 

[ColoradoRaptor]

........had this very same thing happen to me and it was a LOOSE ground!! CPS, possibly due to crank/no start but the other symptoms..... Your money, your Heep................

 

[firefighter19]

per wildman i tested the pins on the c1 connecter for power and neither had power. i guess this means a loose ground? what other grounds are there? i found one near the battery and one on the lower passenger side of the engine and another one on the valve cover on the drivers side

 

[winterbeater]

The orange wire (per 2000 FSM) coming in to the CKP should show 5 volts. The brown / yellow should be ground. So if you check for voltage between those two points, you should get 5V. If not, try checking with the red probe on the orange and black probe on a known good ground. If that works, you have a ground problem. The 5V comes directly from the PCM and grounds within the PCM also.

 

[firefighter19]

no power out of the orange wire, but the brown/yellow wire is grounded

 

[winterbeater]

So you need to test the orange wire coming out of the PCM for 5 volts. If you have it at the PCM (hopefully), but not at the CKP, there is a break in the wire somewhere. If not, the PCM must be bad. That same wire also feeds the Camshaft position sensor too, as well as almost all the other sensors. If you can find a connector on that orange wire, that unplugs everything, you can make sure that nothing else is shorting it all out. Then check for 5V there.

 

[firefighter19]

i tested the ckp wire and it had no voltage, i tested the input wires to the computer, nothing. where is this other orange output wire??? also, when working on it tonight. we put di electric grease on all fuel injector plugs, distributor, and battery terminals and battery ground. also had my truck hooked up to my buddy's wrangler while the wrangler ran to try and charge the battery. after a half hour i went to start it and the gauges worked except the fuel, the check engine light came on but no code came up on my reader, the electric fan didn't run like it used to. still didn't run, then after cranking a few times it went back to no gauges, electric fan running, no bus, etc. later after the vehicles had just been sitting there, i just turned the key to start, not to crank it and i could hear the electric pump kinda loudly with the gauges working, yada yada, cranked it then back to original symptoms again.

 

[winterbeater]

Di electric grease is an insulator. From what I understand, the connection usually scrapes through, but I always try not to get any on the electrical contact surfaces.

The "other" orange wire comes out of the PCM and runs to the CKP and other sensors. It is right at the PCM.

 

[joe_peters]

Could be your battery has failed. Try charging it overnight (24 hours better) and then see what happens.

 

[firefighter19]

charged battery, new pcm, new ASD relay, now the fan, ac clutch, fuel pump, and new ASD relay just click on and off when the key is in the on position

update: has fuel and spark