Starting this thread to document my experience with the P0016 and P0018 codes. There isn't much information out there on this code combo, or at least resolved cases. Found a few threads where people had issues but the final fix was never posted. I'll follow up on the diagnosis and eventual fix once it's been resolved (hopefully sooner than later!).

Vehicle info:
-2005 4Runner Sport V8 (VVTi)
-135k miles, oil change @ approx 133k, timing belt done @ 100k, all other maintenance up to date
-Truck has never had any sort of engine issues or check engine lights except for the 'air injection system'.

CEL event info:
-Out running weekend errands, had been to a couple places and was pulling onto highway when dash lit up.
-CEL, VSC off all popped on SOLID.
-Pulled over on shoulder and turned off truck. Hooked up the scan tool and got:

P0016-(Bank 1 Sensor 'A')
Crankshaft Position-Camshaft Position Correlation

P0018-(Bank 2 Sensor 'A')
Crankshaft Position Camshaft Position Correlation

I did a quick search and found out what the codes were. I fired the truck back up and listened for any irregularities in sound, checked RPMs, etc. The truck was idling as normal, no performance lags or limited power. Luckily I was within a mile of my mechanic who also did my timing belt job so I drove it straight there. There was zero change in the way the truck drives and no power loss. As he was busy on Saturday I dropped if off later that day after picking up my girlfriend's car and he'll be checking it out this morning.

I should mention I also erased the codes using the scantool and they did not come back on until about 5 seconds after I fired up the truck the second time AFTER the reset. In other words: I erased the codes. Turned truck on and drove it - zero lights on dash. I then shut off the truck and turned it back on and after 5 seconds, dash lit up.

Here are the other threads I found on this issue:
P0016

P0016 on V6

V8

The only thing I didn't do which I probably should have was to pull the battery cable and reset the truck (not 100% sure if this is different than resetting the codes but I feel like it is). The fact that I have an interference engine AND both banks threw the code lead me to believe it's not just a sensor issue but it was running normally hence my confusion. Either way those factors led me to play it safe so I'll hopefully have some more info and a happy conclusion soon.

**Update:

Taking the truck over to High Tech @Scott@Hightech as I really trust their mechanics and their ability to diagnose potential VVTi issues. I'm leaning towards it being the mechanical timing since it seems to be running just fine and both banks are registering faults. I had the mechanic who did the timing belt at least do an oil change to rule out oil or sludge issues (even though I highly doubt that was the cause)

**High Tech UPDATE**

Looks like timing belt skipped a tooth or two due to faulty/failing belt tensioner. Serpentine belt (unrelated) was also in pretty rough shape so replacing that as well. Another unrelated item is very worn SPC (light racing) UCA ball joints have a lot of play. Not too happy about this but I ordered 2 new ones from Wheelers and will swap them in when they arrive. I only had about 6000 miles and 6 months on them...VERY disappointed. I'll give them one last shot and see how these ones fare...otherwise I'll upgrade to some uniballs down the road.

**FINAL FIX UPDATE**

High Tech came through and set the timing back up. Timing belt had skipped a tooth. Scott replaced the belt tensioner and put on a new serpentine belt (old one was showing some wear).

Big thanks to Scott and Matt at High Tech. Truck is running better than ever!

Sounds like fun....... I did a quick search and only saw articles where these codes came up after timing belt replacements that were 1-2 teeth off. I doubt after 35k miles the timing belt is installed incorrectly, but it may have jumped a tooth. One or 2 teeth off will not usually cause a drivability problem other than the CEL.

Shouldn't be too hard to figure out though, see you this afternoon

Sorry I didn't get back to your PM, I am actually on Vacation right now for a couple of weeks so I don't have access to TIS (They IP lock the website even though I need credentials to log in anyways, much like AllData these days... EXTREMELY frustrating and I am too lazy to spoof a work IP address just to have a mobile log in). But yeah it could be that the belt has jumped a tooth or two. This is not entirely uncommon, it sounds like you have a good shop willing to look at the issue though. If you need any more help let me know.

Thanks Scott! Just dropped it off. I'm sure you guys will have it patched up in no time. Let me know if you need any other info.




No worries man and enjoy your vacation! Really appreciate you taking the time to shoot back a reply. Hopefully you're somewhere warm as it's aiming to be downright arctic here for the next few days.

Thanks to High Tech the truck is running better than ever.

I updated the first post with the final fix.

Question I have is was the tensioners replaced when the tb and pump was originally done? And what was replaced in that service?

The tensioner appeared to have been replaced. along with the water pump and timing belt and pullies.

Here are the pictures that show the timing belt being off. Typicall this is very common when installing a timing belt. The T marks you can see are NOT the timing belt marks when you are doing the replacement. They indicate top dead center(0 deg on the crank). The 2 vertical lines on the cyl head about 1/2 to the left of each red T Are the timing marks and there is a corresponding mark on the crankshaft pulley(timing belt) and the block. The whole assembly is rotated just off TDC as to give the valves more room if something were to jump unexpectedly.

Could the replacements been crappy replacements? Cheap Chinese parts? Did you end up going in and replacing everything again?

When I had the 90k service done, yes, I replaced all the mandatory and optional items (water pump, pulleys, tensioner, etc).

Thanks Scott. This is why High Tech is bada$$.

I'm 99% sure I used quality parts for the timing job. I'm pretty OCD and quality oriented on my truck even on non-critical items so I'd be shocked if I skimped on timing parts. While I can't remember exactly the brand I used, I'd wager they were good quality. From what I can tell, I think this was just a freak occurrence. Stuff happens.

I ask because I see tons of 4.7l kits on eBay, Amazon, Rick auto etc. I just bought all Red box oem Toyota stuff down to the seals. $600+worth, didn't want to find out later down the road that this can happen to me.

If you can remember that would help others know what aftermarket brands to avoid.

Glad they fixed it. It's hard to find a good shop that you trust doing your work.

If you got red box then I'm sure you'll have confidence in your timing belt rebuild. I just called the guy who did my timing belt and I'm 99% certain we used the Aisin kit from Olympus Auto Parts (who provide the same parts as OE). So I can't say this occurred due to crap parts.

I completely agree that going quality and OEM will reduce your chances of pre-mature failure and provide peace of mind. But stuff happens and parts break. I'm pretty sure the Toyota dealers use the Aisin brand but I'm sure someone can correct me if I'm mistaken.

Thanks for the reply! I wonder if the oem supplier, let's say it is asin. Puts out a higher grade for oem red boxed Toyota stuff and a lesser quality for aftermarket sales. I know this is true when it comes to aftermarket car stereo stuff. A single manufacture can produce many different grades of products. Cheaper plastics, less cooper stands, bulk packaging and our no packaging. It can drive costs down from $5 to under $2. I am sure this is possible in automotive parts. Look at the 2x2 knock offs of the rigid leds 45 each vs 200 each.

A lot of people tend to use the T Marks for lining it up if they don't know what they are doing (because hey, T for Timing right). I stressed this somewhat in my thread where I showed how to replace the timing belt on my own 4.7L V8 engine.

I'm glad you guys got it figured out and it was pretty benign.

Looking at first picture I can say exactly what happened there. They used right marks but they didn't rolled back cam sprockets by 1.5 and 1 mark respectively. This is very important as I noticed doing my own TB just 4 months ago. I followed FSM ($13 well worth it) to the letter and had no problems with alignment. You also need to be careful when turning these cams, they will jump on you, my hands were all beat up and bloodied from trying to hold them and trying to set them back to right place once cam slipped half a turn lol. When new tensioner installed the marks will align perfectly.

Just did my timing belt and water pump. Thought I did everything with care but now I am getting the 0016 0018 code. I lined everything with the timing marks and not the t. I'm hoping I just pinched a wire but after further reading I saw that you need to turn the cams back a bit. It starts and runs fine but I won't drive it till I either take it apart again or pay someone.

On a positive note, I replaced my fj cruiser rear coils with the OME 895E and I'm really stoked on the ride difference and added lift in the rear.