# Exhaust cam issues?



## Blasirl (Mar 31, 2015)

Zelex said:


> Okay. I am legitimately at a loss for this one.
> 
> I have a 2017 chevy cruze 1.4 turbo automatic transmission. 114k on the clock
> 
> ...


Just looking at what you wrote, I would clean the MAF (using MAF cleaner)t, verify the MAP sensor is ok, 

*P121A code possible causes*

Faulty Fuel Injector
Fuel Injector harness is open or shorted
Fuel Injector circuit poor electrical connection
Read more @ P121a Code - Cylinder Balance Test Injector Restricted
* Chevrolet DTC P121B*
Make:Chevrolet
Code121B
Definition:Mass Air Flow (MAF) Sensor Supply Voltage Control Circuit Low
Description121B Vehicle ON and the engine is not running. The DTC runs continuously when the above conditions are met for greater than 1 s.
Cause:The ECM detects the commanded and actual states of the MAF control circuit do not match for greater than 4 s. 
Read more @ P121B - Chevrolet Diagnostic Trouble Code (DTC) Definition, Causes and Diagnosis


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## Zelex (Sep 13, 2021)

Blasirl said:


> Just looking at what you wrote, I would clean the MAF (using MAF cleaner)t, verify the MAP sensor is ok,
> 
> *P121A code possible causes*
> 
> ...


Thank you so much for the reply, 
I have replaced the MAF already, although I can always try cleaning it as well. I cleaned the MAP sensor as well. It was a little gucky, but nothing so bad it looked like it could impede its performance. Although from what I have read these have two MAP sensors? 

Thanks


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## Blasirl (Mar 31, 2015)

Zelex said:


> P00F4 humidity sensor


I know zilch about this, but here is a picture of one along with the part number:








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and this is a Chevy TSB, but not for the Cruze.


https://static.nhtsa.gov/odi/tsbs/2019/MC-10155007-9999.pdf


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## Zelex (Sep 13, 2021)

Blasirl said:


> I know zilch about this, but here is a picture of one along with the part number:
> 
> 
> 
> ...


I think I may have resolved the ambient temp and humidity ones. Because it looks like the intake pipe coming from the intercooler wasn't completely attached. But I am still getting those three main ones.


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## jblackburn (Apr 14, 2012)

The vacuum pump on the drivers side of the camshaft may be failing or a tensioner/guide is allowing slop in the chain.

I'd take it to a mechanic to diagnose further from here.


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