thinner viscosity oil for sure as the VVT passages are narrow.

I add ATF about 590mi before changing my oil..

When I had my P1388 - I ran the ATF/0W20 combo for about 700 miles and the cel went off on its own and I never had an issue since..

 

Thanks for the info. I'll try this out.

 

Just bought a 2001 Jaguar SType 3.0 with 112k miles. I apologize if this question is not in the right place. On my way to get it inspected I was going to check to see if all monitors were on due to a battery replacement. Engine light came on before I could check and I have three codes, p1383, p1388, po420. No symptoms what so ever, car runs great. Please help with this. I have read info on VVT, downstream o2 sensor mirroring upstream o2 sensor. I thought about replacing cats but I don't know if that would help get rid of the VVT codes or will make no change at all. The VVT solenoids are working properly, no evidence of sludge build up in the valve train what so ever. At a complete loss, I had just done a complete suspension job on this and hate to see her sit due to this. Any help or input would be greatly appreciated.

 

Drain your oil and replace with 5W20 or 5W30 and new filter and sub 1qt of that oil w/ Dexron Trans fluid. This will clean out the small VVT oil passages.

Also, confirm your car's PCM was updated as there was a software recall regarding VVT on the 3.0 engine.

 

Thank you for your help. Would this also help the p0420 or should i go ahead and put the new cats on then tackle the vvt issue with the oil change and atf. What brand of oil filter do you recomend. I will also ck to see if the update was done. Thx again for your help

 

Not sure if you swung by the new members section. If not, please take a moment to post an intro.

I would use the cheapest oil and oil filter you can buy as you will only leave this in with the 1qt of trans fluid for about 1,000 - 1,500 miles then change it out.

It takes time for the trans infused oil to work its way through the VVT passages so drive it as normal, don't baby it.

As far as the P0420 put it in the search and read up. There could be other issues causing the P0420, mainly misfiring coil(s) on the offending side of the motor. A lazy downstream O2 sensor might be the cause as well but I'd first focus on clearing up the P1383/1388 codes first.

Finally, make sure your reading the correct O2 sensors on the correct bank... Changing the CAT will not fix your VVT issues.

 

Rather than using ATF, I would suggest that you consider using Marvel Mystery Oil. It contains Stoddard solvent, and has been on the market for almost a century. It's safe and very effective for this type of usage. Use one quart per oil change.

 

Thank you for the advice, keep ya posted after i try a few things.

 

I think it was already mentioned, but you've got two separate issues going on. Both are fairly common so don't go into FullPanicMode™ yet.

For the VVT (P1383 and P1388), try the advice already offered about the engine oil. I wouldn't change any parts ($$$) until you've tried fresh oil. FWIW, I've had these codes a couple of times previously and an oil change was all it took for me. I didn't doing anything to flush out any potential sludge. The VVT mechanism seems to be very sensitive to viscosity breakdown, flagging those codes long before any other ill effects make themselves known.

For the converter efficiency code (P0420), don't change that cat yet. There is lots of discussion in this forum about catalyst efficiency fault codes. To search for them, make sure you type "P0420", not "Po420" as you typed above. The second character is a zero, not the letter 'O'. A typo like that in the search will throw your results way off.

I've had the dreaded P0420 code, after a misfire (oil collected in the spark plug well) that was since corrected. Here's what I taught myself about catalyst efficiency fault codes:

Before pulling the trigger on a replacement cat, I decided to replace the upstream O2 sensor on a hunch. The P0420 code is determined by sampling "dirty" exhaust entering the cat, as measured upstream. The sensor sends out a reading and the PCM instantly adjusts the air/fuel ratio to compensate, constantly switching back and forth. The switching rate upstream (fast switching is basically good) is then compared to the switching rate downstream of the cat, where the switching rate should be slower to indicate the cat is cleaning the exhaust as designed. Since sensor switching tends to slow as they age, I tried a new upstream sensor to increase the difference.

Please note I kept the old sensor downstream, as slower switching there is good. The difference in switching rates between the upstream and downstream sensors is VERY important. Don't change the downstream sensor, because a new one will have a faster switching rate and this will decrease the difference from upstream. You want to maximize the difference from upstream to convince the PCM that the exhaust is cleaner as it leaves the cat.

That's what I did on my '02 V6 and everything is happy. I also suggest changing the upstream sensors on both sides. They are cheap (I got a Bosch brand for about $25 each on Amazon) and are a normal wear and tear item. The PCM makes so many decisions based on the O2 sensors, and I feel it's best to keep both banks similar. I'd certainly gamble on a normal wear and tear item before replacing an expensive cat that may still have plenty of life left in it.

 

All good advice, but I think the upstream O2 sensor is more likely to be the culprit, not the downstream one. Basically, a lazy sensor is good in the downstream position, as a slow switching rate there is what the PCM want to see to indicate the exhaust is cleaner as it leaves the cat.

More of my crackpot theory in post #29.

 

Mike,

The viscosity issue doesn't have a clear cut answer as it relates to VVT operation.

In post #3, Brutal suggestion for thicker oil makes a lot of sense, especially on a higher mileage engine. To expound on what he said, clearances open up in other areas, specifically in the main and connecting rod bearings. This extra clearance lets more pressurized oil escape back into the crankcase. In other words, a decrease in restriction anywhere after the oil pump causes overall oil pressure to drop. This decrease is a well known condition on any engine, and a good workaround is to run thicker oil. Is this a perfect solution? Not exactly, but it is thoroughly adequate and sure beats the expense of an engine rebuild. Oh, anyways, if oil pressure has been slowly decreasing like that, there may not be enough muscle force available for the VVT monkey motion to work properly.

On the other hand, if the fault is caused by sludge buildup in the narrow passages in the VVT system, then thinner oil (and possibly some cleaning agent) may be what you need to get through and restore normal operation.

So it all boils down to picking your poison. You've got to make an educated guess. It could be the VVT fault is caused by low oil pressure in the whole engine, and therefore thicker oil is recommended. Or it could be the oil pressure is fine but the narrow passages are restricted, so thinner oil make more sense.

I like the previous suggestion to check for sludge at the oil filler cap. That should give you an idea which direction to go. Also keep in mind thicker vs. thinner is not a permanent decision. Try one option and if that is no help, try the other at the next oil change.

 

You are absolutely correct!

That's what I get for responding while tired...lol

 

Thanks to everyone for the advice. I spent the money on upstream o2 sensors, no change. I then spent lots of money on two new cats and that fixed that problem. Now for the VVT, i have changed the oil to 5w20 with 1qt of atf. If no change after 500 to 1500 miles i will try the thicker oil option. I will get the p1383 and p1388 at the same time, after clearing the codes i will get one or the other. I hope one of these options work, has anybody had to actually spend the money on replacing the VVT or has everyone got lucky. The reflash was done and verified so i know that is not the problem. Thanks again for all the input.

 

The ATF and low viscosity oil should do the trick. (You did sub 1qt of oil for the ATF, correct?) It takes a couple hundred miles of driving to get those passages to clear up. My p1388 took about 2 weeks of driving to clear up.

The good news is once the VVT passages are cleared up the CEL will disappear on its own. I rarely have ever heard of VVT units going bad. Clogging up yes but not going bad. If one or the other VVT is flagging then the oil/ATF mix is starting to do it's thing.

Once you get the VVT's cleared up start to put a bit of ATF about 500mi before changing oil. I also use engine flush at each oil change. I let engine idle for 20 mins then drain used oil.

Glad to hear you got the efficiency issue sorted though.

 

Yes, used 5w20 with 1 qt of atf. I will keep ya posted.Thx

 

To clarify i substituted 1 qt of atf for 1 qt of oil. Thx

 

Good talking to you on the phone today.
I'll do more thinking/remembering about the 3.0 VVT issues. I have not seen this in a long time but maybe DATALOGGER will help while the engine is running??

Let me know when you can get the car to me for some diagnosis.

Maybe I can verify the calibration files to ensure that the 'reflash' was done.

bob

 

In Britain there is a firm which uses soya oil to clean the engine internally. This could cure this problem.

Their web site is here for more information Improve Your Car | Engine Cleaner Treatment | EDT Automotive.

 

At about 236K Mi I got the P1383 and 1388 codes.

First tried adding ATF to oil as described in this thread, ran for about 2K Mi, but it didn't help. Replaced the VVT solenoids, that didn't help either. I ran out of time and needed to pass emissions to get my registration renewed. Wound up having the timing chains replaced ($$$) and that fixed the problem. Apparently the VVT actuators are still in good shape. At this mileage on the (Ford / Porche designed Duratec family) 3.0 V6, it's not unexpected to see timing chain wear. I have been having oil analysis done at every oil change (Blackstone Labs) and everything has been pretty much within normal range for trace metals, viscosity, contaminants, and TBN, so I think the engine should be good for at least another 100K Mi. (It owes me now!) It is a very comfortable car and handles well, so I don't feel too bad about keeping it a few more years.

More notes on my high mileage S-type:
I made several repairs after 200K Mi including new fuel pump, radiator, heater control valve, replaced rubber parts including coolant hoses and serpentine belt (& tensioner). Also one ignition coil and one injector. In a few months, I think I will replace all of the injectors with a set of re-manufactured ones. I'll get a spare Motorcraft brand DG528 coil to keep on hand. From experience, I would suggest replacing the fuel pump as routine PM on *any* vehicle at 200K before it fails and leaves you stranded.

Another suggestion (off topic) from experience is to stay away from the 5R55 transmission in any vehicle unless it has been replaced with a competently re-manufactured one. Not a local tranny shop rebuild. The 5R55 family (by Ford) has a design flaw: The reverse and mid band servo bores are not sleeved by OEM. The bore is through the aluminum die casting and is subject to premature wear. One early symptom is leaking of transmission fluid onto the exhaust system (I think from the breather) producing intermittent smoke that gets sucked into the cabin. It shows especially when stopping at the end of a freeway off-ramp. This leakage symptom can mostly disappear once the fluid level gets down to about a quart low. Other symptoms that could be from bore wear or from low fluid are: Transmission dropping into neutral by itself after coming to a full stop; also a distinct lag in downshifting, especially from low speed ~20mph to WOT. A later symptom is occasional intermittent slipping as the bore wear gets worse due to leakage past the increased bore clearance reducing the available hydraulic pressure. (and fluid sprays from the leak into the case.) So, due to various potential transmission problems, stay away from S-type 3.0 V6 prior to about 2004 model year. (2003 ZF had some problems of its own.)

 

does the software reflash only go for 3.0 engines?