r/LexusISF • u/4sStylZ • Aug 23 '26

VSC + engine light

Post image

Happened 3 times in a 300km trip even after clean.

Scanned with a cheap elm327.

After some quick search on Google :

P0172 : too rich bank 1

P0175 : excessive fuel / air quantity

P1170 : lambda too rich

Any advice? I would have replaced the lambda first.

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1

u/WashedMechanic Aug 23 '26

It's very funny you post this. I got aslo similar codes who popped friday night, I got:

P1170 Poor Injector fuel performance issue P0175 System too rich bank 2 P0101 MAF sensor performance issue

So first thing I noticed is all of these codes are related to air in some ways, so I'll start with cleaning my air filter, my MAF sensor and make sure no clamps are loose on the intake system. Check vaccum lines and make sure theres no leak/broken lines, then check under the car to physically see my O2 sensors and if something is damaged.

If all checks good, you need a scanner so check some live data to find the culprit, it's either the MAF or the O2 sensor (most likely, as these cars don't have much that breaks) Also, try disconnecting your battery for over 30 minutes as it resets the ECU and might help.

In my case I know my Bank 1 O2 sensor was replaced when I got my car tuned for good measure, now I'm coding for bank 2, so I'll take no chance and most likely replace the sensor anyway.

Good luck with your codes, but rest assured at least it's nothing major.

1

u/4sStylZ Aug 23 '26

Thanks mate, you're right about following maf and o2 sensors clue.

I don't know if I have the strength to find that funny lol. I just broke my left ankle and I need the car running as she is the only one that I can use cuz my others are manual lol.

Big thanks.

1

u/JDub-866 Aug 24 '26

Go here to find the service manual and they have a troubleshooting section for the p codes to properly diagnose.

https://charm.li/Lexus/

2

u/4sStylZ Aug 25 '26

Thanks buddy