Check Engine Light: the case of the codeless conundrum

[Human]

So, yesterday I was out running errands and when I got back in the car (2013 LaCrosse eAssist pseudo-hybrid with 18,500 miles on the odometer) at one stop and cranked the engine, the 'check engine' light came on. The car was running okay, so I cut my errands short and drove home to get my OBD II scanner and check for codes. Weirdly, there weren't any. The light was on but there were no codes showing. I cranked the car and let it run for a minute, did this a couple of times, actually, and the 'check engine' light persisted. Rather than drive myself crazy, I decided to disconnect the scanner, close up the car, and go inside and fix some supper. I chose not to worry about the car until I got in it this morning to drive to work, and when I cranked it, the check engine light was off. With any other car, I would have dismissed it as a glitch in the system, but given some of the issues I had with my other 2013 LaCrosse, I tend to be overly sensitive to this stuff, and a codeless check engine light is the kind of thing that drives me nuts.

 

[richardnewton]

A better code reader might be able to pull those codes if they weren't erased.

I don't know if the ones used at the national parts readers can do that.

A low 12v battery can drive some odd codes until the battery is charged up...

 

[Human]

A better code reader might be able to pull those codes if they weren't erased.

I don't know if the ones used at the national parts readers can do that.

A low 12v battery can drive some odd codes until the battery is charged up...

I was thinking the same thing about the code reader. Mine is almost 15 years old and have suspected it of missing codes in the past, so I bought a new one off of Amazon. It's a pretty basic model, but it did detect a P0010 code that the old scanner missed. It found the code despite the check engine light not being on. Good old camshaft position actuator circuit. I had problems with this on my other LaCrosse, replaced the actuators, and then subsequently had to replace the entire timing set, including the actuators, a few months later. I hope I'm not headed down that same road on this with less than 20,000 miles on it, The other car didn't give any trouble until it was at around 85,000.

The 12v battery should be good. Mom had AAA come out and replace it last fall, shortly before she gave me the car.

 

[02LTD2.0]

A properly charged battery should measure 12.6 volts. A battery that reads just 12 volts is under-charged. You should also have it load tested.

 

[Human]

A month later and the check engine light came on again with the P0010 code, and again it went out the next day. I took it to a trusted mechanic and he said it needed VVT solenoids replaced. That and an oil change came to just shy of $420. I was a little irked at the price because I could have ordered the solenoids and put them in myself for well under $100. Oh well, I guess that's the price of getting a professional opinion. I will say the car has gained a small but noticeable amount of power with the new solenoids. The past few weeks, it had started acting like my other LaCrosse, which often doesn't have anough power to get out of its own way. All in all, I'm not exactly impressed with the EcoTec four-bangers.

 

[richardnewton]

The cam solenoids get cooked on these 2.4 engines. Some think the internal coil wires fail intermittently when heated.

Ours looked fine, actuated cleanly with 12v, and had reasonable ohms readings. But we got the periodic code too.

The Terrain guys recommend changing them in matched pairs. The other soon fails and the system stays matched.

That said, with those vvt codes, sometimes there is more than meets the eye. But with that mileage, it is unlikely the timing set is shot IMHO.

 

[Human]

I agree. My other LaCrosse, which also has the 2.4, required a timing set, which included VVT solenoids, at around 85,000 miles. With this one having so few miles on the clock, the timing set is most likely fine. In my experience with older cars that have low miles, deterioration due to time and disuse is the biggest enemy, primarily in the form of leaks due to perished seals and oxidation of electrical contacts.

 

[richardnewton]

Our cam solenoids died around 40k miles. That car has a lot of short hops so faced a lot of heat cycles.

The rubber accessory belt also deteriorated over time. Thousands of micro cracks which were tough to see while installed on the car. Maybe good for 10 years but I don't remember the recommended change interval. The belt and tensioner were upgraded I think, so replace both as a broken belt can cause some more damage (particularly to the generator bracket but also whipping around can damage more parts.