P1694 No Bus not CPS

Yesterday my Jeep was running fine. This morning, I got in it to go to an interview for a job and as soon as I turned the key, the electric fan came on (doesn't normally do this.) It cranks for a little bit, then the no bus in the odometer comes on and the check engine light comes on. The fuel and voltage gauge don't move when I turn the key on. They also don't move when I unplug the Crankshaft Position Sensor. I replaced the CPS anyway because I have already done it so I knew how to do it quickly and I figured it's good to have a spare anyway. Still no start and same symptoms.

99 XJ AW4 4.0

I don't have my FSM with me so any help would be appreciated.

ETA: I can't do the CCD (whatever that is) diagnostic procedures because I can't start it to let it idle for 2 minutes

iluv83vettes said:

Yesterday my Jeep was running fine. This morning, I got in it to go to an interview for a job and as soon as I turned the key, the electric fan came on (doesn't normally do this.) It cranks for a little bit, then the no bus in the odometer comes on and the check engine light comes on. The fuel and voltage gauge don't move when I turn the key on. They also don't move when I unplug the Crankshaft Position Sensor. I replaced the CPS anyway because I have already done it so I knew how to do it quickly and I figured it's good to have a spare anyway. Still no start and same symptoms.

99 XJ AW4 4.0

I don't have my FSM with me so any help would be appreciated.

ETA: I can't do the CCD (whatever that is) diagnostic procedures because I can't start it to let it idle for 2 minutes

Click to expand...

I have same year and engine as you, with same problem of no bus. that means vehicle cannot communicate with PCM. For me it was an issue with grounds of ASD relay, etc. Check your ground cables and pcm connections.

iluv83vettes said:

Yesterday my Jeep was running fine. This morning, I got in it to go to an interview for a job and as soon as I turned the key, the electric fan came on (doesn't normally do this.) It cranks for a little bit, then the no bus in the odometer comes on and the check engine light comes on. The fuel and voltage gauge don't move when I turn the key on. They also don't move when I unplug the Crankshaft Position Sensor. I replaced the CPS anyway because I have already done it so I knew how to do it quickly and I figured it's good to have a spare anyway. Still no start and same symptoms.

99 XJ AW4 4.0

I don't have my FSM with me so any help would be appreciated.

ETA: I can't do the CCD (whatever that is) diagnostic procedures because I can't start it to let it idle for 2 minutes

Click to expand...

You don't have to start the Heep to check the CCD Data Bus voltages. In fact, you are not to run the engine while checking the CCD Bus (+) (-) voltages.

JeepNovice said:

I have same year and engine as you, with same problem of no bus. that means vehicle cannot communicate with PCM. For me it was an issue with grounds of ASD relay, etc. Check your ground cables and pcm connections.

Click to expand...

Good idea to check the grounds. There have been cases (rare) where the ground(s) below the ignition coil bracket are corroded. This ground point is essential. See pic below for itemized listing of the circuit grounds at G101.

Sidewinder CC said:

You don't have to start the Heep to check the CCD Data Bus voltages. In fact, you are not to run the engine while checking the CCD Bus (+) (-) voltages.

Click to expand...

If you need to go further with checking the CCD Bus voltages let me know.

Grounds are all good. Cables have been upgraded to 5-90's 4 gauge. How would I test the CCD without starting?

Do you have a Sentry Key Immobilizer System?

If you want to check the CCD Data Bus, here's how:

Refer to the schematic below.

Using a digital voltmeter do the following.

Turn the ignition key to RUN, engine not started.

On the Data Link Connector, check the voltage between pin cavity 3 and 4 or 5. Meter (+) probe to cav 3. You should see around 2.49 volts.

Check the voltage between pin cavity 11 and 4 or 5. (+) probe to 11. You should see around 2.51 volts.

With the ignition switch OFF/LOCK and battery (-) cable disconnected.

Using an Ohmmeter set at 2K, read between pin cavities 3 and 11. You should read around 120 Ohms.

These are ideal readings.

If one of the CCD Bus circuits, (+) or (-) is reading too high or too low there may be one of the modules on the CCD Bus causing the problem.

If the resistance reading is 60 Ohms, one half of the CCD Bus (+)/(-) circuit is open. One of the modules, or its wiring, may be defective.

Take some readings and get back.

I'll check readings tomorrow when I get my multimeter and FSM. I don't know if it has the key immobilizer but it came with factory keyless entry which I have never used because the remote that came with it didn't work. I just use the key in the door. It's a limited model with every option except heated seats. I've swapped the Dana 35 to the Chrysler 8.25 and got rid of the abs system. I don't think any of that would affect this though because that was don't a while ago.

Between pin 3 and 4/5 I was reading 2.41/2.42 volts. Between 11 and 4/5 I was reading 2.42/2.43 volts.

Resistance between 3 and 11 was exactly 60. Didn't jump around at all

Also I have been reading in my diagnostic procedures manuals to perform test ver2a etc. Where are these tests outlined?

Just to update, I tested the cluster in accordance with the FSM and it passed the check so the cluster isn't faulty.

The voltage readings are not that wild but the 60 Ohm reading shows there is a defect in the Bus. Generally there should be about a .02 to .150 volt differential between the Bus (+) and (-) circuits and I do see a split in your voltages so I wouldn't be concerned about that now.

You say "The fuel and voltage gauge don't move when I turn the key on." Are you saying your instrument cluster is dead? Looks like it.

There have been cases where the instrument cluster causes the 60 Ohm reading, whereas one of the CCD Bus wire connections in the cluster connector C2 is open, or the same result from a defect in the cluster module itself. C2 pins 1 and 2 are the CCD Bus connections.

Some folks have fixed this by complying with the TSB to replace the C2 connector and others have fixed this by replacing the cluster.

Other modules or the PCM are not out of the woods on your original problem of the P1694/No Bus, however.

If you had SKIS, your ignition key would look like this:



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The fact that the radiator cooling fan turns on when the key is turned to RUN is odd.

Do another voltage check at the DLC. This time turn the key to OFF. Probe 3 to 4/5 then 11 to 4/5 and see what you get. You should see the differential between the (+) and (-) circuits (ref. the voltages you got with the key to RUN. As a note, my differential is .02 volts.

Leave the key OFF.

Go to trhe PDC and pull the cooling fan relay and probe between pin cavity 85 (ref pic below) and the battery ground post. You should see near what the differential voltage was. It may be lower but never batt voltage. This is the PCM idle voltage (differential) on the relay control coil ground circuit to the PCM. If it shows the (near) PCM idle voltage that control coil ground circuit is okay. Pin cavity 86 should read zero. With key to RUN, 86 should read batt voltage and 85 may change a bit.



Check this out and see what you get.

~~~~~~~~~~~

I don't know what that ver2a test is. Here's the P1694 diagnostics steps.

Sidewinder CC said:

The voltage readings are not that wild but the 60 Ohm reading shows there is a defect in the Bus. Generally there should be about a .02 to .150 volt differential between the Bus (+) and (-) circuits and I do see a split in your voltages so I wouldn't be concerned about that now.

You say "The fuel and voltage gauge don't move when I turn the key on." Are you saying your instrument cluster is dead? Looks like it.

There have been cases where the instrument cluster causes the 60 Ohm reading, whereas one of the CCD Bus wire connections in the cluster connector C2 is open, or the same result from a defect in the cluster module itself. C2 pins 1 and 2 are the CCD Bus connections.

Some folks have fixed this by complying with the TSB to replace the C2 connector and others have fixed this by replacing the cluster.

Other modules or the PCM are not out of the woods on your original problem of the P1694/No Bus, however.

Click to expand...

I tested the instrument cluster and the results were what they should be according to the Factory Service Manual.


[/QUOTE]
If you had SKIS, your ignition key would look like this:


[/QUOTE]

My key is the more triangular shape than the circle shape. I doubt the SKIS would have caused this problem because I have used this key since I bought it and never had a problem. Plus, there was nothing done to it from when I turned it off Wednesday night to when I tried to start it Thursday morning.

~~~~~~~~


[/QUOTE]
The fact that the radiator cooling fan turns on when the key is turned to RUN is odd.

Do another voltage check at the DLC. This time turn the key to OFF. Probe 3 to 4/5 then 11 to 4/5 and see what you get. You should see the differential between the (+) and (-) circuits (ref. the voltages you got with the key to RUN. As a note, my differential is .02 volts.

Leave the key OFF.

Go to trhe PDC and pull the cooling fan relay and probe between pin cavity 85 (ref pic below) and the battery ground post. You should see near what the differential voltage was. It may be lower but never batt voltage. This is the PCM idle voltage (differential) on the relay control coil ground circuit to the PCM. If it shows the (near) PCM idle voltage that control coil ground circuit is okay. Pin cavity 86 should read zero. With key to RUN, 86 should read batt voltage and 85 may change a bit.



Check this out and see what you get.
[/QUOTE]

When the key is off, I get no voltage between pin 3 and 4/5 as well as between pin 11 and 4/5. I held the probes for my voltmeter and was reading 0, then turned the key on and it started reading 2.41-3 depending on if I was on pin 3 or pin 11.

Pin 85 hole of the fan reads 0.02 and pin 86 reads 0 (with the key on, it was reading battery voltage.)


~~~~~~~~~~~
[/QUOTE]
I don't know what that ver2a test is. Here's the P1694 diagnostics steps.



[/QUOTE]

I would be nice if I could start the vehicle so that I could follow the steps that are outlined there.

As I am thinking about it more, it almost seems like the PCM had a hard shutdown when I turned it off and is still set up for how it was running right before I turned it off (A/C on and up to operating temperatures so fan is running). I don't know, just an idea

I'm having the same problem now what's the ending to this story here I feel screwed ATM

When Sentry Key (SKIM) has problems, the engine will start and run for 2-3 seconds and then shut off. Repeated attempts to start with a SKIM fault will lock up the PCM. The symptoms described do not point to a SKIM problem.

If you have a P1694 and /or a P1698 code, you should suspect a faulty Crankshaft Position Sensor (CPS) and/or issues with the CPS wire harness, despite what the trouble codes point to. See the linked info:

http://www.naxja.org/forum/showthread.php?t=63167

http://wiki.answers.com/Q/What_does_code_p1694_mean_for_a_2000_Jeep_Cherokee

P1694 Fault In Companion Module. No CCD/J1850 bus messages received at the power train control module (PCM) from the AisinWarner Transmission Control Module (TCM).

P1694 will set if no CCd bus messages are received from PCM for 20 seconds or invalid messages are received for 20 seconds.

Possible Causes
-CCD Bus (-) circuit open between PCM and TCM.
-CCD Bus (+) circuit open between PCM and TCM.
-Transmission CCD bus wiring damaged.
-Faulty TCM
-Faulty CPS

When the CPS short circuits the engine computer (PCM) shuts down to prevent damage to itself. As a result, there is no communication (P1694).

Disconnect your crankshaft position sensor then put the ignition key in the on position. If the instrument cluster starts to work once the CPS is disconnected, then you know the CPS or CPS wires are shorted and is the root cause of the codes.. You can verify this by testing the CPS and checking continuity on the CPS wires.



P1698 No CCD Messages Received From PCM. Bus communication failure to PCM. A "Companion DTC" was set in both the ECM and PCM.

Possible Causes:
- Faulty Engine control Module (ECM)
- Engine control Module(ECM) harness is open or shorted
- Engine control Module (ECM) circuit poor electrical connection

ruffrich26 said:

I'm having the same problem now what's the ending to this story here I feel screwed ATM

Click to expand...

I just took it to a shop. They spent two days finding a 2 shorts. One was to the fuel pump and when that shorted out it fried the fuel pump, so I needed a new fuel pump too. The place was really nice and only charged me an hour labor to find and fix the shorts. They ran a new wire to the fuel pump.

Sidewinder CC said:

Do you have a Sentry Key Immobilizer System?

If you want to check the CCD Data Bus, here's how:

Refer to the schematic below.

Using a digital voltmeter do the following.

Turn the ignition key to RUN, engine not started.

On the Data Link Connector, check the voltage between pin cavity 3 and 4 or 5. Meter (+) probe to cav 3. You should see around 2.49 volts.

Check the voltage between pin cavity 11 and 4 or 5. (+) probe to 11. You should see around 2.51 volts.

With the ignition switch OFF/LOCK and battery (-) cable disconnected.

Using an Ohmmeter set at 2K, read between pin cavities 3 and 11. You should read around 120 Ohms.

These are ideal readings.

If one of the CCD Bus circuits, (+) or (-) is reading too high or too low there may be one of the modules on the CCD Bus causing the problem.

If the resistance reading is 60 Ohms, one half of the CCD Bus (+)/(-) circuit is open. One of the modules, or its wiring, may be defective.

Take some readings and get back.

Click to expand...

I have been having a problem with the gauges not working for a few weeks now. I have searched high and low for the issue. Have tried all the tricks and checked all the grounds. I came across this post about using meter to ohm between 3 and 11. I get 0. I got a different meter and got 0. This is with batt neg unhooked. With it hooked up and key on I get 0 vdc on either of the bus pins at data connector. I’m not sure what is supposed to give power to the bus line but I am getting nothing. If I do the gauge test all the lights work and sweep properly. Air bag light is on. Nothing else. Turn signal and headlight indicators do come on. Not getting any no bus error on odometer. Jeep drives and runs fine. Looking for some kind of direction to head from here.

Thank you so much in advance.
-g

Since this post I went out and changed the meter to 200 instead of 2000 and I get a reading of 22. With everything unplugged but the airbag module it is currently reading 27 didn’t know if this was helpful info.