P0300, P0301, P0303, P0304 and VSC TRAC VSC OFF lights! All at once.

[lifer]

The 2000 LX470 (178k miles) has been running great, no recent changes, no LED bulbs (to my knowledge), light off-roading 10 miles every other weekend or so. I loaned it to my 16-year old daughter to get to school and after a few day all hell breaks loose. While she was driving back home the CEL, VSC TRAC, and VSC OFF lights came on and the engine started misfiring. I checked the codes this morning and got P0300, P0301, P0303, and P0304 - all indicating misfiring on cyl 1, 3, & 4. Quick google revealed similar trouble code pattern in Lexus ES300 was traced to a bad Oil Control Valve (OCV) aka VVT control valve. I'm tempted to go get one and replace it. I'm thinking that the shake from the misfiring is setting off the VSC TRAC and VSC OFF lights. Anybody had a similar problem?

 

[Jason YY]

I had the exact same codes prior to my timing belt breaking. I strongly doubt that you are going to have your timing belt break. I had planned on changing out the two "bad" coil packs to get rid of the codes.

When I had the belt repaired, the mechanic recommended changing the spark plugs before chasing any misfires. So that is what we did, about 1K on the new plugs and no misfire codes.

Edit
my codes were actually
P300,P302,P304 .P306
with the VSC TRAC and VSC lights going on

 

[Julian Stead]

It does sound like valve timing if it affects 1 bank of the engine, whether it is belt or vvt system im not sure. I would check valve timing and belt condition for piece of mind as it could of jumped a tooth.

 

[lifer]

I was thinking it was one bank, but I came across a photo that shows the cylinders are numbered all odd on the drivers (right) side and even on the passenger (left) side so now I'm not so sure. I think it's unlikely that multiple things went out simultaneously whether plugs, vvt valves, or coil packs but plugs are cheap so I could start there. I have a lot of data from the "deluxe" code reader. Does anyone know what the timing is supposed to read? I just looked at the spark advance while idling and it ranges from 6.5 to 12.0 degrees, slowly changing up and down.

 

[Jason YY]

One thing I still notice is my oil pressure seems "High" and I am kind of hijacking your thread in that regard. I guess , a search on that VVT control valve will tell me more. But have you looked into what it does and are there many reported failures?

 

[Julian Stead]

Was any fuel put in before the issue, just incase it is poor fuel, just a thought. You could swap coil packs around to see if fault codes change. Remove and check plugs, but for multiple failures it just seems odd.

 

[lifer]

Negative on the fuel, (16-year old girl not likely to fill up LX470 tank!), but more to the point, the fuel level is about the same as when I gave it to her - about 1/4 tank left. Good idea to swap around coil packs and plugs. At least not just throwing parts at it. The VVT oil control valve is supposed to work by controlling oil pressure to some kind of actuator on the cam shaft that adjusts timing. Based on the live feed to my OBD2 meter, it is wandering all over from 6.5 to 12.0 degrees of advance at idle, so that seems to indicate a failure in that system. The valve has an electrical connection on top and I guess it is fairly easy to get to in the valley on top of the V8 after removing the plastic shroud. I think I'll get a replacement valve and swap out the one on the drivers side to see if that does it. I remember changing plugs to iridiums last year, so I don't think they are the problem.

 

[davegonz]

Sounds like coil packs. Amazon actually sells them for a good price. Try swapping them around to see if the codes change first.

Amazon.com: Denso 673-1303 Ignition Coil: Automotive

 

[Julian Stead]

You said it is spark advance, this isnt valve timing advance, two different things.

 

[lifer]

Good point. Maybe the engine computer is moving around the spark advance to try to compensate for the valve timing problem. I don't know of a way to check valve timing.

 

[Julian Stead]

I dont think the igntion timing will alter to compensate, it just advances and retards in relation to engine knock. I would try just swaping around the coil packs on the right side as its easy to get to and see if the fault codes change. You can disconnect and reconnect the coils when it is running to find what cylinders are misfiring, then swap the coils with a known good one to see if the fault moves with it, if that makes sense.

 

[arcteryx]

As Dave mentioned, swap out a good coil pack, ie, 5-8 and put them in 1,3 and 4 and see if the code moves to the new cylinder. If it does, replace them.

When mine occurred, I had numerous codes and lights and it ended up being a stuck #6 valve. Compression was zero, which is very odd as even bad engines give some compression. So you may want to do a comp test if the above doesn't help.

 

[lifer]

Fixed it! Thanks everyone! I swapped coil packs between cylinders 1 and 7. The problem went away on cylinder 1 and did not appear on cylinder 7. Then I installed all eight new coil packs and the engine ran better than ever since I've owned it over a year. All codes cleared and no more warning lights. I would swear it has more power too.

I used these coil packs and they worked great!
Amazon.com: ECCPP® New Set of 8 Ignition Coil on Plug Coils Pack For Lexus GS430 GX470 LS430 LX470 LX570 SC430 Toyota 4Runner Land Cruiser Sequoia Tundra V8 B277 UF230 5C1196 9091902230 9008019027: Automotive

These coil packs fit more snugly on the plugs and the engine harness connectors - that means a better fit in my opinion. The engine harness connectors can be difficult to get the snap lock to click. A little dielectric grease on the seal would probably help a lot.

Some observations: The coil packs go through the valve covers and if the seal is not good, oil can pool around the spark plug. ( That was the case on #5 but didn't cause a misfire.) The seals become hard with age. Some seals are soft silicone and others have hard material overmolded with rubber. The soft ones work better.

The failure of one weak coil pack appears to cause others to become weak and throw codes. The coil pack failures appear to disturb the electrical system and cause the VSC TRAC and VSC OFF lights to come on. After looking at many VSC light posts, a common cause was an electrical disturbance (LED light swap on the PRND2L shift indicator, ABS connectors loose, cable abrasion near the back turn signal/brake light). I saw the VSC lights turn on again 2 or 3 times soon after replacing my coil packs. After a couple of days, that went away. I think the ECM had to relearn the new voltage baseline after installing the new coil packs, but after a few days it was stable.

I would recommend replacing the whole set at 100k miles along with the plugs.

 

[2001LC]

Interesting you had codes indicating coils on both side and Jason YY had T- belt go out. Could the erratic miss firing of coils knocked-out a weakened T-Belt. Be my guess.

 

[lifer]

Fixed it! Thanks everyone! I swapped coil packs between cylinders 1 and 7. The problem went away on cylinder 1 and did not appear on cylinder 7. Then I installed all eight new coil packs and the engine ran better than ever since I've owned it over a year. All codes cleared and no more warning lights. I would swear it has more power too.

I used these coil packs and they worked great!
Amazon.com: ECCPP® New Set of 8 Ignition Coil on Plug Coils Pack For Lexus GS430 GX470 LS430 LX470 LX570 SC430 Toyota 4Runner Land Cruiser Sequoia Tundra V8 B277 UF230 5C1196 9091902230 9008019027: Automotive

These coil packs fit more snugly on the plugs and the engine harness connectors - that means a better fit in my opinion. The engine harness connectors can be difficult to get the snap lock to click. A little dielectric grease on the seal would probably help a lot.

Some observations: The coil packs go through the valve covers and if the seal is not good, oil can pool around the spark plug. ( That was the case on #5 but didn't cause a misfire.) The seals become hard with age. Some seals are soft silicone and others have hard material overmolded with rubber. The soft ones work better.

The failure of one weak coil pack appears to cause others to become weak and throw codes. The coil pack failures appear to disturb the electrical system and cause the VSC TRAC and VSC OFF lights to come on. After looking at many VSC light posts, a common cause was an electrical disturbance (LED light swap on the PRND2L shift indicator, ABS connectors loose, cable abrasion near the back turn signal/brake light). I saw the VSC lights turn on again 2 or 3 times soon after replacing my coil packs. After a couple of days, that went away. I think the ECM had to relearn the new voltage baseline after installing the new coil packs, but after a few days it was stable.

I would recommend replacing the whole set at 100k miles along with the plugs.

UPDATE: After a 1+ year of running great, the P0300 and P0303 codes reappeared with misfiring, CEL, VSC TRAC, and VSC OFF lights coming on. I saved the good coil packs from last year and will pop one onto the #3 cylinder.Lexus Workshop Manuals > LX 470 V8-4.7L (2UZ-FE) (1999) > Maintenance > Tune-up and Engine Performance Checks > Firing Order > Component Information > Specifications

 

[lifer]

UPDATE: After a 1+ year of running great, the P0300 and P0303 codes reappeared with misfiring, CEL, VSC TRAC, and VSC OFF lights coming on. I saved the good coil packs from last year and will pop one onto the #3 cylinder.Lexus Workshop Manuals > LX 470 V8-4.7L (2UZ-FE) (1999) > Maintenance > Tune-up and Engine Performance Checks > Firing Order > Component Information > Specifications

Update: P0302 code appeared with rough running. Replaced #2 coil pack and runs great now. Those cheap coil packs seemed great but 25℅ failure in 1+ years is crap.