SureTrack Community Fix: Hummer Time

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Timing is everything, in life and engine operation. SureTrack community member Jeffytune had a low mileage 2006 Hummer H3 in the shop that they had to rebuild the cylinder head but then was setting a code for timing after reassembly. They posed the question to the community, and with the help of fellow community member CampsallsAuto and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

Vehicle
2006 Hummer H3 3.5L

Title
Code P0017 after cylinder head replacement, reset timing.

Complaint
Cylinder head rebuilt, now engine runs fine but sets code P0017.

Diagnostic Steps Performed/Parts Replaced
This vehicle spent most of its life at a condo in Hawaii and only used a couple times of the year and only has 18k mile. New owner brought it in after buying it and it had codes P0174 and P0300 for running rich and misfires. Testing revealed intake valve seat wear and engine has low compression.
We removed the cylinder head using the special GM tools. Before removal, I used a TDC tool to ensure it was at TDC, the exhaust gear showed the “Delphi” logo was level with the head. On both of the dimples, I cleaned the oil off and used a paint pen to mark the location, as well as marking the exhaust gear’s front sensor ring to the body to make sure it all went back the same way it came out. I was very attention detailed in the reassembly, everything is lined up and the engine is running smooth. It does not stall, but it is setting a code P0017 (Cam correlation).

I removed the oil control solenoid and it looks fine. The plunger moved with power and the screens were in place. We still replaced it (With AC Delco part) and tried again with same result. We tried to use the scan tool to operate the solenoid, but once the code sets it will not run the test. We then hooked power and ground to the solenoid, and with the engine running, we applied power. The engine RPM changed, and at 1000 rpm, it made the engine stall. There is power and ground to the solenoid from the computer and there is power and ground to the sensor. Since GM did not decide to give us a PID for cam sensor, I backprobed both, but I can not find a “Known good pattern” to compare mine to it to see if it is really out of time or if the computer is failing to read it right. Is there a PCM update to correct this code? Could it be a timing issue brought on by surfacing the head?

And guys, please remember that it is 5.5 hours just to remove the valve cover (Intake has to come off) and the reason we bought those GM tools, to pull the timing cover requires removing the engine, it’s over 18 hours. If you know where I can find a known good cam/crank correlation pattern I would be very grateful.

Best Answer from Community Member CampsallsAuto
I’ve seen this code come up lots of times with being 1 tooth off on the camshaft timing. Also have seen the camshaft solenoids (camshaft gear itself) fail. If you can turn the camshaft without the camshaft gear moving I would replace the camshaft solenoid, it’s activated by the oil pressure from the oil control solenoid to adjust timing. If it’s not responsive, the engine will throw P0017. Hope this helps.

Cause
Well I went and bit the bullet and pulled off the cam cover/valve cover and used the new and improved service bulletin (06-06-01-017G) method of setting the timing chain. What I found was that wile the “Links” lined up on the gears, the camshafts on the rear flats were not level. The tool would slip on just fine, but that intake cam was advanced 1 tooth, and the exhaust cam was too, but was not at full advance, once as full, it was off the same amount. After resetting the cams, the engine ran just fine, thankfully we did not bend a valve. The lesson here is, always check the TSB’s for updated information. Now weather the cam chain was off from the extreme poor running when it came in or if some how I slipped a tooth with the factory hold tools in I can’t say, but to take off the timing cover would have been a 17 hour job, and pulling the engine out.

Correction
Reset cam timing. The computer is happy and it runs fine, and the customer is happy so I am calling it fixed.

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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.