2016 Chevy Malibu limited LT
What does it mean when you press the brake an RPMs are below 500 when in Drive mode. but when depressed it goes back to regular RPM?
I just had to clean my MAF Sensor and change my aux battery bc it threw code: P305F. After i cleaned the MAF. So issue is resolved and its normal for the car to be in gear while on the brake to be below hash mark below 1. But live data shows its still over 600 RPM.
It might help if we knew your vehicle details. You left out a few details that are clearly asked for in the posting instructions...
Its a 2016 Chevy Malibu limited LT and when my foot is on the brake while in gear the RPMs are below 500 but when depressed the RPMs goes back to normal operating. What could be the cause or what part should i replace?
When what is depressed the RPMs go back to normal?
So while in gear when i press down the brake pedal the rpm below 5 and when i lift foot while in gear it goes to normal
Lifting your foot off the pedal is the opposite of "depressed" - the pedal is depressed when you step on the brake. Have you checked for codes or analyzed live data to see what's going on when this happens?
Yeah i know what it means that’s why i retyped it i figured y’all would follow what i was trying to say. But no didn’t do any live data because its not throwing a code.
Just because there are no codes (if that's the case) doesn't mean there are no issues to be found in live data. You may also have pending codes that have not yet triggered the check engine light.
Its a 2016 Chevy Malibu limited LT and when my foot is on the brake while in gear the RPMs are below 500 but when depressed the RPMs goes back to normal operating. What could be the cause or what part should i replace?
With your foot pressing the brake pedal the RPMs drop, when you remove your foot from the brake pedal the RPMs go back to up to normal. Ok.
First off don't go replacing anything. More diagnostics are needed. It 'might be' several things. Might be electrical, it 'might be' caused by a vacuum leak.. worsened when you step on the brake pedal activating the brake booster. Depending on whether the car is running too rich or too lean, the rpms could increase or decrease.
@chucktobias suggested examining the live data. Examining the data changes occurring when you press the brake pedal down and after you release it offers insight/clarity as to what's happening with the engine during this time.
Ok i will hook up my scanner to read while running with live data. Thanks you guys will be back with updates soon.
When i tested it the MAF Drops and then when i let up off it went back to normal.
Adding @chucktobias @mmj other members for opinions.
I agree it's probably the brake booster. If it's vacuum boost, then disconnect the hose and plug it. That should tell you right away.
Thx @mmj , was starting to doubt my initial suspicions
I agree it's probably the brake booster.
That's a good possibility. A couple of years ago a friend's car cut out on him while on the road due to sudden failure of the brake booster creating a huge vacuum leak.
when depressed it goes back
When i tested it the MAF Drops and then when i let up off it went back to normal.
Why are you testing the MAF sensor? It won't hurt to clean the sensor but what's needed is the interpretation of several live data parameters over several minutes, like STFT & LTFT values, at various RPMs. Jumping around guessing at this or that is illogical and counterproductive. What's the mileage on this Malibu?
Im pretty sure its the hose to the brake booster cause it’s not my engine its dealing with my brake pedal being pushed while engaged. She has 218k miles on it with great maintenance done on her
Why are you testing the MAF sensor? It won't hurt to clean the sensor but what's needed is the
Sorry, I meant to ask you "How" you tested MAF. Did you check flow with a scan tool, did you use a multimeter? Was there a code?
Im pretty sure its the hose to the brake booster cause it’s not my engine its dealing with my brake pedal being pushed while engaged. She has 218k miles on it with great maintenance done on her
Adding @chucktobias @mmj other members for opinions.