NEED HELP Momentary P0016 after COLD start

[Chickenhawk]

I am chasing a P0016 that only comes on after a very cold start. (Usually -16C or below.) The engine runs normally, and if I shut it off and restart, it does not display any symptom of a lost cam position. It seems to only last a few minutes. If I erase the code using my BlueDriver, it will not come on again until the next deep cold start.

I am suspicious of a ground issue or perhaps an oil issue.

I replaced the CPS and the CPAS. (AC Delco) My old CPAS was only three years old, and came out very clean and no oil in the connector, but replaced it anyway. Oil is 5W-30 and fresh. No signs of sludge. Performance is as normal as the day I got it.

I have a multimeter but no Tech2. I haven't started looking at the CPS connector quite yet as it seemed very sound when I put in the new CPS. But based on the fact that a CPS connector is a common aftermarket part and based on having to replace my blower fan motor connector that SEEMED good (but was fried inside) I am suspecting the connector or perhaps a ground farther down the harness. The reason I suspect a ground is because grounds have a tendency to not connect well on very cold days. (Shrinkage.)

The reason I am coming here first is that there are no other codes; I don't know where the ground comes from anyway, and if a ground was at fault, would it not throw a code for other components? I am also not sure of the difference between P0016 and P0341.

It also seems to have started after my last oil change. I went from a 5W-30 Mobil 1 oil to a MotoMaster (Shell) Synthetic 5W-30 High Mileage oil. (I have just over 210,000 KM)

If the oil is suspect, I have no problem draining and refilling if needed. Ideas?

 

[Mooseman]

We have a very good thread on that:

p0016 keeps returning

I recently replaced cam shaft and crank shaft sensors I've also cleaned Camshaft Position Actuator Solenoid, Now a little backround SES light was on I pulled a p0016 code I replaced cam sensor light stayed off for about a week, light came back on pulled same code. replaced crank sensor again...

gmtnation.com

Did you try cleaning the cam sensor?

However, because it happens when cold, I'm thinking it's something with the cam phaser or the oil pressure. You should put a real oil pressure gauge on it and see what pressures you get cold and what it does as it gets warm.

Not having a Tech 2 or other advanced scanner does hinder at diagnosing this.

 

[Chickenhawk]

Yes, I read that thread. The difference is that mine does not stay on. I am guessing it only lasts a minute or two when first started. I can erase the code after the engine is a bit warmer and it never comes back until a few weeks later when it was -24C and I couldn't plug it in. CPS and CPAS are brand new AC Delco.

I think I will run half a can of seafoam through it and change to Mobil 1 5W-30 and see what happens. I am suspicious of high-mileage oil, and what they use to help seal those seals and gaskets. The other reason why I am suspicious of the oil is that it was only run for a couple of minutes before the oil change and left to drain for two hours. Maybe there was still a bit of sludge that was not liquified yet.

 

[mrrsm]

If the changeover to Mobil1 5W-30 was not coincidental with the ACDelco CPAS R&R... It is very likely that some of that sludge is trapped inside the CPAS Screens and may call for its removal and a decent cleaning with Brake-Kleen, etc. to "Manage its Mischief".

If you've been using the vehicle lately when that activity is very coincidental with the problem of the prevailing Deep Cold, it will have become a magnet for any small animals nearby trying not to freeze to death during the night.

If they've been getting underneath and later on top of the Motor for the sake of comfort because they instinctively know that heat rises ... chances are, they've accidentally chewed into some of the wire looms and harnessing just to pass the time... making the setting of the P0016 Code entirely possible from nearly broken harness wires.

So it won't hurt to look things over under the hood very closely (but cautiously) for any signs of Rodent Activity in mind. If some of the Hood Liner has been pulled loose and added to other nesting materials of pine needles, leaves and animal fur and the upper engine and wheel wells are peppered with the most dangerous stuff of all... concentrations of Feces and Greasy Urine (with a Nasty, Deadly Hanta Virus in tow).

That Bug won't be conducive to your health should you accidentally inhale its dusty, deadly residue or touch any of it with your hands and fingers and transfer it into your mouth or eyes. 36%-40% of the people infected die with symptoms looking much the same as a serious Covid-19 Delta Variant Infection. Using an N-95 Mask, Protective Lenses and some Nitrile Gloves are the suggested additions for a close inspection under there with a Bright Flashlight.

 

[Mooseman]

that sludge is trapped inside the CPAS Screens and may call for its removal and a decent cleaning with Brake-Kleen, etc. to "Manage its Mischief".

I DO NOT recommend using brake cleaner as that will destroy any seals, internal or external, in the CPAS. Carb cleaner would be better.

 

[budwich]

your time for "deep cold" is probably getting "thin" but if it does come by again, get a hair dryer and hit the area(s) in question before your start attempt and see if that changes with warming a particular area (ie. connector or device).

 

[Chickenhawk]

Can anyone tell me what readings I should get at the CPAS connector? The CPS connector is normal and no sign of broken wiring. I am really focusing on the CPAS right now. It is brand new, so I am still thinking the oil or a ground/wiring problem at the connector.

 

[TJBaker57]

Can anyone tell me what readings I should get at the CPAS connector? The CPS connector is normal and no sign of broken wiring. I am really focusing on the CPAS right now. It is brand new, so I am still thinking the oil or a ground/wiring problem at the connector.

As in readings with a test meter?? Readings from the PCM or from the disconnected solenoid?

I found a resistance spec for the solenoid itself of 8 to 12 ohms.

I have PID definitions for use with smartphone apps for observing the duty cycle from the PCM to the CPAS.

 

[Chickenhawk]

Multimeter readings on the connector itself from the PCM. The solenoid is brand new, AC Delco in a sealed bag. I know the cam position sensor connector should read 12V when ignition on, and continuity to ground, but the two wires from the PCM to the connector on the CPAS are control wires, so I am guessing there should be a resistance reading between the terminals.

 

[TJBaker57]

As far as I remember there are 2 wires from the PCM to the CPAS. 1 is a "low reference" which is sort of a ground that is monitored and controlled by the PCM. There should be a very low resistance to chassis ground from this PCM wire. The other wire is a PWM signal from the PCM. In my tests of several P10 PCMs (02-05) this will be an open circuit to ground.

For the sensor the red wire is as you say a 12 volt power with key on. A pink/black wire at terminal C is another low reference and that again should measure a very low resistance to chassis ground. The last wire, a brown/white is the pulse signal from the sensor back to the PCM. In my tests of PCMs on the benchtop I read about 56k ohms from here to ground but this was with a fully disconnected PCM. Don't know what you might see otherwise.

Now you've given me an idea ! Having recently dipped my feet into the world of Arduinos' I'm wondering what I would see measuring the pulse timings with the Arduino. I'm like a kid with a new toy!!

 

[Chickenhawk]

From what I can gather so far is the two wires from PCM to connector have a voltage reading, depending on how it commands the solenoid. In one video, I saw 8 volts reading between the two wires with the key ON but not started.

The solenoid will have a resistance of 8 to 12 ohms between the two terminals. Plus, it should actuate with a voltage applied to the two terminals of 9 to 12 volts.

I think I will pick up some accessory test leads with alligator clips to test my connector. The alligator clips (Napa Canada has them) will allow me to wiggle the connector around a bit to see if there is a momentary connection from a partial break in the wire.

It wouldn't hurt to also test the resistance of the new solenoid.

I am also changing to fresh oil as soon as the weather warms up. (Minus 27C right now. Not great for working under the hood.)