Throttle Body re-learn after cleaning it

[Mr Vlad]

Well today even though cold but dry I finally got to clean the MAF sensor and the throttle body (as best I could). Following numerous videos I disconnected the Battery then removed the MAF sensor (that's an easy clean). After removing the duct pipe from airbox to throttle body I disconnected the multi plug to it. Took the 4 bolts out but there are 2 pipes connected to it and they look a massive pain to disconnect so I left them but in doing so it made manoeuvring the body very limited. Anyway copious amounts of spray cleaner and use of microfiber cloths I cleaned both faces of the body. Very surprised how much dirt was there. 

Anyway after leaving it all 30 mins so the spray cleaner evaporated I put everything back together. After a coffee I went to the car and started it. Oooops revs shot to 2 thousand and stayed there. Oh pooh I thought. So I took it for a near 10 mile run including motorway. Got back home idle dropped to 1500 revs. Mmmmm still not happy so I googled it. Found 2 items of interest. 

1st video I've seen before. is250 specific. Method. Turn car on but not to start (so the needles go round then back) do that twice. Start car. Put handbrake on then into drive. Leave to idle whilst in drive for 4 minutes. Turn engine off. Repeat. I did this but my revs were now 1000-1100.

2nd video from a GM guy which actually made sense. Because in essence it was like a new throttle body the PCM needs to re learn. So this video says similar to first one except: Method start car and let it idle for 3 minutes. Shut off. Wait 1 minute. Start car again let it idle for 3 minutes. Shut off. Wait 1 minute. What I noticed was on the 2nd cycle (of 2nd video) the idle reduced to 750-800 revs. I took the car round the block flooring it where I could lol.

Low and behold car idles as it should. 

Thought I'd post this so if anyone is thinking of doing the same and the same problem occurs you'll know the cure.

Judging by the dirt in the throttle body thats a job once a year ( in warmer times)

[Mr Vlad]

Well I did that cleaning job a month ago now. Have I noticed any changes? Yes. The car runs so much better. The throttle response is much better. This car now shoots away from the lights (yes ok I use a little more throttle now but not as much as you think) and is actually a nicer car to drive. Yes it sounds daft maybe but yes a nicer car to drive. I thoroughly recommend you do this to your cars. Oh and yes I have taken into account that its ruddy cold out there and has been for weeks which means the air is denser which in turn means more oxygen going into the combustion chamber before anyone tries to pee on my bonfire. 

[JDM-Fiend]

What cleaner did you use to clean the throttle body and MAF?

 

I'm considering doing this before fitting my intake kit.

[nicnac]

https://www.amazon.co.uk/Liqui-Moly-Sensor-Cleaner-200ml/dp/B00295EEBK/ref=sr_1_1_sspa?dchild=1&keywords=liqui+moly+maf+cleaner&qid=1613385251&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyQldGUjgwOUtXWUhHJmVuY3J5cHRlZElkPUEwMjIzOTk5Mk9DUllKUjg2VjlCUCZlbmNyeXB0ZWRBZElkPUExMDQzMTUzMVc2QTFCMkc0WEdUSCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

[Mr Vlad]

Hi Chan. I used CRC Maf cleaner for the maf sensor and CRC throttle body cleaner. Used CRC as it's got the best reviews and they're really excellent products. 

[don4229]

My car is 2017 GSF which is quite different from yours. 😊 The below is the idle learning procedure for my car directly from Lexus factory service manual. Hope it helps.

Idle Learning Turn the engine switch off and wait for at least 30 seconds. Start the engine and warm it up until the engine coolant temperature is 80°C (176°F) or higher. HINT: Learning starts when the engine coolant temperature is 80°C (176°F) or higher. After the engine is warmed up, allow it to idle for 5 minutes with the air conditioning and all accessories off. Confirm that the idle speed is within the specified range. Standard: Engine Idle Speed 700 to 800 rpm HINT: Be sure to perform this step with all accessories off. Make sure that the shift lever is in N. Make sure that the electric cooling fan is off.

[eleveneleven]

Is this something Lexus do as part of their servicing? 

[Texas]

Simply put….No

They ( Lexus dealerships) don’t even lubricate caliper slide pins when/if they renew brake pads/discs and when ( not if ) they seize will gladly fit New callipers at £££££’s all day long!

So if a maf sensor is out of spec they will want/recommend fitting a new one at ££££’s again!!!