P0021 - 2007 Toyota Tacoma 4.0L

Hello,
I am struggling to solve the issue with my Tacoma. It has 205,000 miles on it and has recently begun acting up.

I was driving to work when the Check Engine Light (CEL) came on. Shortly after the CEL came on, the red oil pressure warning light came on. I immediately pulled over and quit driving. I checked the oil and the fluid was between the two notches on the dip stick and it only had around 1500 miles since the last oil change. The oil appeared very clean. I added some new oil to the truck to get it to the top notch just in case. This made the red oil light go off, so I began driving it home. Shortly after, the red oil light blinked a few times and then came on solid so i pulled the truck over again. I towed it home and began my diagnosis. I recently bought the truck and am not sure what all has been done to the Tacoma. I have had it for around 700 miles. The pickup appeared to be running with no symptoms of an issue other than the two warning lights.

I scanned the Tacoma and found the code was P0012 and P0022, "A camshaft position timing over - Retarded Bank 1 and 2" respectively. So I began by changing the oil and filter. I decided to do the spark plugs while I was at it. I also decided to just go ahead and replace both Variable Valve Timing(VVT) Solenoids and the PCV valve. I cleaned the throttle body and the MAF sensor while I had it apart.

I put it back together and cleared the previous codes. I fired it up and it immediately kicked on the CEL. I scanned it again and this time I got a P0020, "A camshaft position actuator circuit/ open bank 2". This code would be kicked on even without the vehicle running. So I went back in to what I had done and realized that I did not get the electrical connection on the bank 2 (driver's side) VVT solenoid all the way connected. I cleared the codes again and it did not kick the CEL light on. So I thought the problem was resolved. I drove the truck to work the next day and it was running fine until it kicked on the CEL after a few miles of driving. When I pulled up to the next stop light it was idling very rough when I was stopped. If it was at higher RPM's (while driving) it seemed to run fine. I drove it home to re-diagnose.

I scanned the Tacoma this time and got a P0021 code - "A camshaft position timing over - advanced or system performance bank 2". At this point, I am very confused but continued to try to diagnose a few things. I cleaned both the camshaft position sensors and pulled the small OCV oil screens and cleaned them. Neither sensor nor the screen appeared to be excessively dirty. After I put it all back together. It kicked on the P0021 code again after only a quarter mile, and the truck was idling very rough.

Not sure what the issue could be at this point. Seems like something I did caused it to start kicking a different code and began idling much worse. Any help or suggestions would be greatly appreciated.

Thanks

 

Im probably guessing it's your timing chain tensioner it could be losing tension & the chain must be stretched that's why your getting timing issues seems like u might have to replace the chain & tensioner. I know the cause of this issue is from not changing your oil regularly especially if you use conventional oil & going over its intervals sludge can mess up the VVT system causing the chain tensioner to plug up & loosen the chain since it works by hydraulic pressure using oil.

 

Is there a good way to attempt to verify that before just diving in and replacing those? When I bought it, there was a leak in the timing cover that I am going to fix, so I need to to pull the timing cover anyways.

 

Oil warning light coming on intermittently and the oil level is registering on the stick?

Id start by looking at oil pressure and the condition of the pickup tube in the pan

 

Would the pickup tube being clogged or covered in sludge cause these different error codes related to the timing to come on? The oil pressure light did come on intermittently briefly and then stayed on. Since the oil change it has not come on again, but i have not driven it very far either. I will drop the oil pan and look at the suction tube to see if there is any buildup.

 

well since u mentioned about removing the timing cover u might as well remove the oil pan too to see what's going on I would check the condition of the chain & the tensioner by removing the whole chain & checking if it has stretched & if it is I would replace the whole chain as well as the tentioner but make sure u have the new chain first so you can do a side by side measurement to see if the original has stretched.

 

I think my plan will be to go ahead and replace both the chain and tensioner while I am in there at this point and look into a few of these other possible solutions including oil sludge and chain stretch. I am also going to replace the water pump while I am in there.

Is there an aftermarket chain and tensioner that people are using or should I stick with OEM? Same with water pump?

I also cannot find a comprehensive list of parts/seals/gaskets that I will need to do the job. Does anyone know what seals I will be replacing while I tear it down this far? With the current state of how long some things are taking to ship, I would like to order everything now in case places in town do not have it and I then end up waiting on parts for long periods of time. I have not found a thread that has this information.

Thanks again

 

The variable valve timing system needs oil pressure to move the cams (advanced/retarded)to a desired position. Those codes are trying to tell you that the pcm is commanding the cams to move but its not seeing the movement it would like to see.

If you had codes and no oil pressure warning light you could look at the oil control valves, filter screens, chain timing/stretch, etc. But you've got a bigger problem than just chain stretch.

the low oil pressure warning is a symptom that needs to be looked at before you start replacing chains and guides. If you slap a chain on there, put it back together and the oil supply and pressure is still not correct you'll be in the same spot you are now.

Yes the chain may have stretched or jumped time and there's a good chance you'll be dealing with that eventually too but you need to figure out the oil supply issue before you can safely reset/replace the chains and timng components

Long story short, before you pull the timing cover I would try to put an oil pressure gauge on it and see whats up. The engine needs to be able to run to check oil pressure. If no gauge is available then at least drop the pan and look at the pickup tube to see if its blocked

 

https://www.tacomaworld.com/threads/code-p0022.492501/#post-23208466

 

Playing devil's advocate here - it could be issues with the VVT solenoids and/or filters, and he could have a bad oil pressure sending unit. I think I'd test that sending unit before diving in and taking the front of the engine off. Diagnostics are free.

 

I put a pressure gauge on it tonight and it is reading 70 psi while the truck is idling in N. It is reading 60 psi while it is idling in D or R. The light has not come on since the original time it came on, so I am not sure how to get it to duplicate those conditions, but there must be an underlying cause for the original time it came on.

I am going to check the inspection port to the tensioner on the timing cover and see if there is any stretch. I will also drop the oil pan and check that pickup tube before I begin pulling the timing cover.

I was not aware that there is a quicker fix to the timing cover leak rather than removing it entirely. Is the fix without removing the timing cover as good?

 

good stuff

 

I removed the inspection port to look at the tensioner. From what I can tell, there is no movement on the tensioner. It does not have visible rings from extending, nor does any art of it appear cleaner or anything indicatiing any movement.

 

So I pulled the oil pan and inspected the pickup tube. It appears to be in great shape with no blockage or sludge buildup.

The tensioner is tough to see on the left hand side of this image through the mirror, but it seems to be in good shape and has no signs of movement.

The oil pressure tested at 70 psi in N and 60 psi in D. I let it idle for five minute at that pressure. Now I am not sure what to check. I dropped all the oil out of it to inspect the pickup tube. In the bottom of the oil pan I did find some very concerning pieces of a some rubber material? gasket maybe?

 

After further inspection, the pieces of gasket are definitely from the oil pan gasket and probably occurred while i was removing it, so nothing to worry about there.

 

That looks like old and brittle FIPG which may be one of the reasons your timing cover is leaking. Be happy it ended up in the pan and not clogging a vital oil galley

 

Yeah, no doubt about that. Could have come from up there too, but it looks like the oil pan gasket had a few spots where it was missing material. Who knows, I just am very confused why I am reading good oi pressure and there is no sludge buildup anywhere. The next step is to remove valve covers and look at the timing closer? To see what is causing these codes to be kicked on and why the idle is so rough suddenly....

 

So have you diagnosed the oil pressure sender unit?

 

How do you do that?