Help 2000 XJ p0304, p0300, p0303, p1694

I am hoping to get some help with my issue. I have a 2000 XJ 4.0l 134,000 miles and I have been trying to resolve a check engine light issue. It first started after I overheated due to a blown head gasket, cracked the cylinder head and had it replaced. A couple of days after getting it back from the shop I get the first p0304 engine light, took it back to the shop, he read it, and cleared it, and it ran fine for about 6 months. Then the light came on and it was p0304 again but the Jeep was running perfectly, no issues. I went ahead and changed the spark plugs because the shop had put in Champions & I have never had good results with them. Reset the code but it came back the next day also accompanied with a rough idle. Next I replace the coil pack, reset the the engine light, but it comes back on the next day also with a p0300. I researched various forums and decided to replace the injectors with upgraded 4hole squirter injectors. The next day p0304 is back, but this time on my way to work the engine light begins flashing and the engine is missing badly, no power, and wont go above 3k rpm. I pulled over turned it off for a few seconds maybe 30, then restart and it runs fine (still has rough idle intermittently). So next, I replace the crank position sensor, and the cam position sensor. The next day same problem p0304, and the sputtering & engine light flashing, turn off, restart & it runs fine.
Finally today it was running fine (engine light still on) i pull into work and the engine was idling in Park and the guage cluster "blinked off for a second".
Later I pulled the DTC's and had a new one, p1694 also p0300, p0303, and p0304. Is it a bad PCM???? is there a way to have it tested? i cant afford changing any more parts that dont fix the problem.
Please help....

I would make sure you cam sensor is sync'd first and foremost and if it is, then the most likely culprit is the crank position sensor. http://jeep.blackonyx.net/pdfs/jcss.pdf

I replaced both crank & cam sensors last week, but didn't help. I even cleared the PCM, or ECU whatever you want to call it to reset the adaptive memory but problem still exists. I am really puzzled today by the p1694 code...

At a loss for ideas.......

Not replace, synchronize. -> http://jeep.blackonyx.net/pdfs/jcss.pdf

P1694 P1698
http://www.naxja.org/forum/showthread.php?t=63167

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).

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.



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:
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. You can verify this by testing the CPS and checking continuity on the CPS wires.

DTC 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.

P1694 Diagnostic Procedure
1. Using scan tool, clear TCM DTCs. Start engine and let idle for at least 2 minutes. Using scan tool, retrieve TCM DTCs. If DTC P1694 returns, go to next step. If DTC P1694 does not return, go to step 5.

2. Check instrument cluster gauges for proper operation. If fuel gauge and speedometer operate properly, go to next step. If fuel gauge and speedometer do not operate properly, see appropriate INSTRUMENT PANELS article.

3. Turn ignition off. Disconnect Gray PCM harness connector. PCM is located at left front of engine compartment. Disconnect TCM harness connector. Measure resistance of CCD BUS (-) circuit (White/Black wire) between TCM harness connector and Gray PCM harness connector. If resistance is more than 5 ohms, repair open in CCd BUS (-) circuit (White/Black wire). If resistance is 5 ohms or less, go to next step.

4. Measure resistance of CCD BUS (+) circuit (Violet/Brown wire) between TCM harness connector and Gray PCM harness connector. If resistance is more than 5 ohms, repair open in CCd BUS (+) circuit (Violet/Brown wire). If resistance is 5 ohms or less, replace TCM.

5. Conditions necessary to set DTC P1694 are currently not present. Inspect related wiring and harness connectors. See WIRING DIAGRAMS. Repair as necessary. If no problem is found, check for broken, bent, backed-out or corroded terminal pins. Check for chafed, pierced or partially broken wires inside insulation. Repair as necessary.

gradon, thanks for the article. I will check the cam synchronizer. I wouldn't have thought of that, although my XJ has never stalled or not started it does have the missing and clearing up upon restart.

Thanks

Thanks Tim MN,
I will try the synchronizing first, and then if not resolved I will use your troubleshooting recommendations.

Much appreciated

Tim_MN said:

Not replace, synchronize.

Click to expand...

Instructions: http://www.jeepforum.com/forum/f11/how-reindex-camshaft-position-sensor-1145301/

Just verified that the camshaft synchronizer was in perfect alignment per the directions you showed. So now I have ruled that out, what is left? I still have the same p0304, along with occasional sputtering, no revs above 3k rpm, and blinking engine light. Turn off engine and it goes away. I have not had any of the other codes come up in over a week, never had the p1694 again. any other ideas???

Take off and clean all grounds: dipstick, head, fender@pcm

I will give that a try. the one at the dipstick head is covered in grease. I will let you know...

Thanks

Checked and cleaned all grounds. .2 ohms resistance between all points, cleared codes p0300, p0303, p0304... Road test, ran smooth but after 20 min. or so the CEL came back on..... p0304 as usual. Not idling rough or noticeably missing though. I am stumped. any other ideas?

Does it rev above 3K now? Do you have the pre-cats right under the intake manifold. I thought it was p0303 that was the typical code due to that 3rd injector boiling the gas after shutoff on 2000s and 2001s with Cali emission pre-cats, but maybe the 4th injector does it too, thus p0304.

yes,
on the last drive it was running smooth, it doesn't always have
the missing & not reving above 3k, only when the CLE is flashing & that only happens once or twice a week (intermittent), but always turns on the CLE p0304. As stated in the previous post, new head, injectors, crank sensor, cam sensor, coil, plugs....
What is left? The PCM or wiring????

Also, put heat shields on all 6 injectors

Want to buy a XJ with a 5.5" Rubicon XDuty lift?
Ha Ha Ha....

Need new ideas........

If only one code left, P0304 is a misfire detected at cyl 4, on yours a shop would tackle all the plugs then run, if still a miss detected, then we would start blaming the coil ( pretty sure yours is cop, if not then cap, rotor, and wires along with the plugs)

P0300 is general miss detected, I believe cyl 3 and 4 (p0303 p0304) are fired by the same coil so im still thinking coil.

I have already been through all of the components you mentioned & the 2000 XJ does not have a cap or plug wires. It has a coil on plug rail & uses a cam & crank sensor. I know what the trouble codes mean, you should read my previous posts before you comment.
Thanks

K read all your post there fella not one mention, someone else posted the p1694, sorry I missed the part where you already did the coil. Mmm still blamin the ignition maybe compression, leak down test?