hello , am having problems with the check engine light , the reading is p0171 + p0174 , I allready checked the intake leaks and replaced the air filter but still have the same problem , is it the o2 sensor ? how many has my car ? can anybody help me please? thank you.

 

check the fuel trim reading when held at idle and then 2500rpm. If its adding fuel ( (mt 10%) at both idle and 2500rpm...check the fuel pressure with a fuel pressure gauge. if the fuel pressure is low...replace the fuel pump.

 

thank you very much, it has a lot of logic what you say, it shows that you know and although it is very helpful , but I will have to take it to a mechanic because I do not have the means to do it myself.

 

I don't answer pm. post your update here.

 

hi, I had problems with the engine check light and you suggested check the fuel pressure, but I do not have the gauge. Then I changed the two upstream o2 sensors and the engine improved a bit, but two days ago the engine turned off and when I started it did it with shivering and turned it off, I left it for a few minutes and managed to start it again to bring it home, on the highway at 3000 rpm it did not exceed 30 m / h and in the reading of defects saids that had problems in sensors 1 and 2 in both blocks and regulation of injection too poor in both blocks. I wanted to know your opinion of the problem, thank you very much.

 

same codes setting or new ones? if new ones...post the codes

 

those are the new codes after the engine stops for 3 times
P0131 SENSOR 1 BLOCK 1 -LOW TENSION
P0137 SENSOR 2 BLOCK 1 -LOW TENSION
P0151 SENSOR 1 BLOCK 2 -LOW TENSION
P0157 SENSOR 2 BLOCK 2 -LOW TENSION
P0171 INJECTION REGULATION TOO POOR
P0174 INJECTION REGULATION TOO POOR
P0299 SYSTEM OF ADJUSTMENT AFTER CATALYST TOO RICH
P0297 SYSTEM OF ADJUSTMENT AFTER CATALYST TOO RICH

 

the first 4 codes are for low 02 sensor voltage
the next 2 codes are for fuel trim lean
the final 2 codes...don't come up for a 2015 suburban so either the scan tool is your are using to retrieve the dtc is messed up or my service information is missing something

are you using flex fuel? any aftermarket cai installed?
if yes, go in with the scan tool and read the flex fuel percent displayed in scan tool data for the pcm/ecm

 

am using E 85 , is 85% ethanol , but I didnt any modification on the system . is it posssible that P0171 and P0174 are caused by problems on the gas pump? thank you.

 

the ethanol content sensor may be reporting bad fuel ethanol %. reset the ethanol sensor. after the tank of e85 is done. fill up with regular fuel and forget e85