2013 GMC Terrain p0017

2013 GMC Terrain 2.4l non turbo with vvt. Vehicle came in Friday after it was previously at another shop where the timing components were replaced. I scanned it, saw a P0017 which if I’m not mistaken pertains to the cam and crank signal aren’t synced. In this case I believed the 0017 is specific to the exhaust cam. I decided to start checking vvt solenoids because they’re easy and right on top. I started with the intake, it’s a two wire computer controlled solenoid.. a low reference wire and a control wire, digital on/off typical square wave. Ground was good and control was good, 0-12 bolts with no glitches or drop outs. Unplugged the sensor would read 2.42 volts, obviously coming from the computer. Next I checked the exhaust vvt solenoid. This is where things got weird… I had zero volts on the ground wire I also checked it with a test light to make sure It was grounded. Now onto the control wire for the solenoid and nothing. No voltage, no square wave nothing… I unplugged the sensor and saw a voltage reading of 2.43 volts and decided that’s my problem, bad vvt solenoid, ordered one and put it in. Re checked my voltage and nothing. Still zero, no digital square wave at all. Now I’m questioning wether or not this solenoid should be on same as the intake so I took it on a test drive still back probed at the Sensor and it never once came on.. I now decided to do my checks at the computer and the results were the same. Sensor plugged in, back probed at the computer on the exhaust vvt control wire i have no digital square wave, unplug the sensor and the computer both are showing me 2.43 volts about the same as the intake unplugged. Does any one have any idea as to why the pcm isn’t controlling the exhaust cam and more so why I have 2.42 volts on both control wires but no control on the exhaust side. Again results are the same at the computer and at the sensor?? Checks were done KOER and KOEO. I also noticed when unplugging the intake vvt the engine ran sluggish, almost as if it were missing, however unplugging the exhaust vvt while the engine was running had no effect at all on the engine. What’s normal operation KOER at idle of the exhaust cam vvt solenoid and what’s with the 2.4 volts but no control during idle or test drive??

After you installed the exhaust VVT solenoid, did you clear the fault codes? Did P0017 reset? Please be clear about both answers.

Does any one have any idea as to why the pcm isn’t controlling the exhaust cam and more so why I have 2.42 volts on both control wires but no control on the exhaust side.

I believe that answer will depend entirely on what the exhaust camshaft desired angle is while you're taking your measurements. If the PCM desires intake camshaft change but not exhaust, then that'd account for your readings.

Likewise, if the PCM has detected a base timing problem (and set a P0017 as a result), then the PCM will not command any camshaft angle change. That's why the presence of the code is key - if the PCM set P0017 as current, then it won't command the exhaust camshaft to change.

What’s normal operation KOER at idle of the exhaust cam vvt solenoid and what’s with the 2.4 volts but no control during idle or test drive??

Again, that depends on what the PCM desired angle is. :silly: 'Normal' operation will depend on a variety of factors, including engine temperature, throttle angle, engine load, like that.

Yes I did clear codes and the code would set almost immediately but the light wouldn’t come on. Takes a bit to get the light to come on but code sets immediately

As Tyler pointed out the pcm wouldn't allow VVT activation with a base timing issue.

If you could go in-cylinder with a pressure transducer to look at valve timing.....

Another option is to check out ckp/cmp relationship comparing to known good captures taken under the same conditions, eg VVT solenoid unplugged.

You also can activate the solenoid manually and look for a change in ckp/cmp relation just to confirm/discard the solenoid itself is working.

I would not be surprised to hear the base timing is off.

8-;

Anyone have an email I can send some video to? I got lucky and had a Chevy come in with the same engine and I was able to get know good exhaust cam shaft signal vs no signal at all I also got some scan data from both vehicles as well… On the known good desired angle was 5 degrees and actual angle was also 5 on the other vehicle (my problem vehicle) desired was 0 and actual was zero also command was 0… I was expecting some kind of angle with desired but it was all zero. Perhaps because the computer isn’t commanding it, would that affect the desired as well? Sooooo confusing lol

Yes I did clear codes and the code would set almost immediately but the light wouldn’t come on. Takes a bit to get the light to come on but code sets immediately

If the P0017 resets almost immediately, then there's some kind of base timing issue. Incorrect chain installation, failed cam gear, slipped sensor reluctor wheel.

The exhaust camshaft desired angle is a zero because of the P0017. Your known good vehicle has a desired angle because the PCM decided very early in that key cycle that there was no base timing issue.

A cam/crank waveform would be nice to have, since this came from another shop and all. But the result is gonna be the same - going back into the timing chain. PIP4548G is worth keeping in mind. It describes a slipped camshaft reluctor wheel:

f01.justanswer.com/indy-tech/9bde6d42-ae...06ef70d119_P0016.pdf

Read the PI very carefully before calling a camshaft. The pictures are from an LE5 engine, NOT the LEA in your Terrain.

Thanks to all of you for the great information, I appreciate it very much this has been more than helpful!