Hello I have been attempting to diagnose and solve the codes P0016 and P0017. This engine is the 3.6 V6 with DOHC and VVT.

Backstory: My girlfriend bought this car and within 24 hours on a 3 hour trip, the engine blew. I found out that it burned a hole in two exhaust valves and damage to 5 out of 6 pistons were present on the sides of the pistons. So over the next few months I had completely rebuilt the engine. New bearings all around, polished crank, new pistons and pins, machine shop put new valves in the cylinder heads and cleaned them up very well. All new timing components and oil pump. I reinstalled the engine and found I had some wiring issues which I resolved. Engine ran better but still gave me the two codes. So I looked to the crankshaft sensor and saw that the wave form patterns for the crankshaft position sensor active counter were erratic on my scan tool. I ordered a GM genuine crank sensor and put it in and it also improved engine performance but the readings were still somewhat erratic in my opinion. I made certain that the 5V reference, low reference, and signal reference circuits are in perfect condition as well. I even checked the reluctor ring on the crankshaft and it was solid.

I did some research online and found that the cam phasers can throw these codes so I tore down to the valve covers and rechecked the timing with the machined plates for the back of the camshaft flats and stage 1 and 2 are in time. I checked the camshaft phasers by getting a wrench on each camshaft and turning back and forth to see if they each lock with the engine off and found that the intake camshaft phaser on bank 1 was faulty so I drove to oreillys and purchased the right side bank, which is bank 1, intake phaser and replaced it. I thought this was the issue but it was not even though the old phaser was bad.

Did more research and found that the crankshaft reluctor ring can shift counter clockwise or clockwise on the crankshaft so I went back to the crankshaft sensor hole and set up a borescope and videoed the reluctor ring while I turned the crank by hand. Comparing to the source online, the reluctor ring on my crankshaft is very slightly off, however I want the opinion of others if they would be so kind.

CKP active counter (blue) and intake and exhaust camshaft bank 1 active counters.


This is my crankshaft.

If it was the crank reluctor slightly off, it would likely throw codes for Bank 2 camshaft correlation as well.

You said you replaced timing components. Does this include all three timing chains and the guides?

How many miles on this car?

Yes all timing chains, guides, and tensioners along with the crankshaft sprocket and two lower sprockets.
This only has 125K miles.

Something odd I forgot to mention is that the angle variance on bank 1 camshafts will either say 0 25 or 51 degrees but it’* never consistent with one value. Also when I turn the engine off the angle variance will go to 51 degrees strangely on both bank 1 camshafts.

This makes me wonder about the bank 1 cam chain tensioner.

The chain seemed tight. I’m assuming a defective tensioner would give the same symptoms as a stretched chain?
Even with the engine staying in time do you think it could cause the angle variance to be that great?

The thing that catches my eye is the continuous changes in angle variance on bank 1 that you have not reported on bank 2. If the chain was not holding tension, this could be a result. Different than a stretched chain with a good tensioner, which would act normal plus or minus a consistent number of degrees from expected.

The hydraulic tensioners will bounce like those used for the serp belt and throw codes.

Alright I that makes sense to me. I’ll double check the wiring to the cam sensors and then tear it down again. I’ll let you know if I find an issue with the tensioner

I finally got down to the valve covers and found that the chain on bank 1 is very tight and I even had someone cranking while observing. I did find that the chain on bank 2 is far looser however the codes are for bank 1.
Just to be certain… If I am looking at the front of the engine, bank 1 is on the left side correct?

I know that they refer to bank 1 as the right hand bank in the service information.