P0021 - 2007 Toyota Tacoma 4.0L

Might want to figure that out before ripping more stuff off your truck.

 

Beyond just putting a multi-meter on it, it is a fairly simple part. It shows 0.9 ohms bouncing a little lower at times. Not sure on that one what else to do. I need to repair the timing cover leak anyways so I am not taking anything apart that does not need to come apart to do that job.

 

I wonder if the oil pump is intermittently failing. Isn't there a (pressure relief) spring loaded valve in the oil pump that could stick open and let oil pressure go back down into the pan? It's weird that you saw that oil pressure warning light around the same time the check engine light came on, but your pressure readings look pretty good.

If it lost pressure for just a minute it could allow the chain to slip a tooth or two at the cams. Are you sure you didn't hear any rattling when the oil pressure warning came on?

 

I am pretty sure there was no rattling but I was with someone and we were discussing it, so I could have missed it, if it was brief. The CEL came on and the oil pressure light came on a few miles later maybe 10. I will know tomorrow if the timing chain slipped a tooth. Not sure how to diagnose the oil pump. Looks like it is behind timing cover?

 

O had a weird code come up like that on my last truck. It turned out to be the Oil Check Valve on bank #2 very simple to get to. I pulled mine ran power to it it worked but replaced it anyways. Never got the code again.

https://www.tacomaworld.com/threads/oil-control-valve-location.270960/

 

sounds like you are referring to the oil control valves a.k.a. variable valve timing solenoids? I think they are the same thing. I had a P0022 and P0012 come and replaced the OCV’s and it switched to the P0021. So don’t think they are the problem unfortunately

 

Yea that's what I meant, oh well good luck man! Keep us posted for future info

 

Have you tried reinstalling the original OCV for the side with the P0021 yet? To try ruling out a faulty new part?

 

I have not tried reinstalling the original OCV, I did test the new one and it is at 7.9 while the old ones were testing at like 7.2.

 

Should be a quick 5 minute swap. Just to rule out any possibility.

 

I’ve had a similar issue. I’ve got a 2009 Toyota Tacoma and had to take it in for an oil leak. Tool it the the dealership and they had to replace the timing chain cover and the seals and gaskets. Also replaced the water pump. I got the vehicle back and it had the check engine light on with a P0020 code. I took it back multiple times and they said they would fix it but each time they never did. It also never had the check engine light on when it came in.I’m not to sure what to do. Any help would be appreciated it

 

Old thread but I'd be very interested if the OP figured this out? Having the same issues with my 09 after vvt's replaced and new timing chains and phasers.