The OBDII scan read code P0236 y P0171 yesterday today read P0237 y P0101 whats the problem?? Is a Volvo S40 2002 1.9T

you have multiple codes... you should reset your check engine light and then retest... you might have one problem causing several others...

do u have a oil leak are u putting cheap oil

What is the year, make and model?
How many miles on it?

You should know that when the check engine light flashes ENGINE DAMAGE can occur!!!

check for vacuum leaks or a faulty mass air flow sensor. all the codes have to do with engine too lean(too much air).

have the code cleared and see if it comes back, The MAF can go bad, but normally they don't unless your in lots of dust or the air filter is really bad,, check the filter, and reset the code, and enjoy your drive,, you can deal with it when you get home

'P' stands for powertrain-codes will be concerned with engine or trans and are generic, that is they are the same no matter the make of vehicle-OBDII protocol. I.E., a P0171 means a lean reading on bank 1, on a ford, chevy, volvo, toyota-universal general code for all makes and models.

0237 is turbo/ super boost sensor a circuit malfunction
0236 is turbo/ super boost sensor a ckt range performance

P0236 Turbocharger Boost Sensor A Circuit ange/Performance and P0237 Turbocharger Boost Sensor A Circuit Low. I would check to ensure your Sensor is didnt come unplugged and if not I would replace the Boost Sensor. Thanks for Using FixYa!

Sincerely,

JC

for p0171 it could be a few things like intake/exhaust leak,air system,map/vaf sensor,fuel presure/pump,injector(s),ho2s(heated oxygen sensor.