check engine light on

check engine light on, i pulled the codes here is what i have code#177 HEGO system shows always lean (left) and #543 fuel pump secondary circuit failure.what to do?will run fuel pressure test tommorrow if pressure is low replace pump problem fixed? did i answer my own question or could it be something else.but i dont understand just left side showing lean? car runs good and check engine light is not on all the time but when its on sometimes it will turn off when i accelerate hard. all help and info. appreciated, thanks. BILL.

HISSIN50 said:

The O2 could have a wiring, contamination, etc issue. You can use a DMM to check its frequency and amplitude of switching.


The Secondary fuel code can be a ghost code. It means at some point for some reason, the FP lost power. This can be an issue, but many people see this code and nothing was noted before or after.

Good luck.

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O.K THATS WHERE I'LL START, I KNOW HOW TO DO THAT TEST.I DON'T UNDERSTAND THIS STATEMENT COULD YOU EXPLAIN,"This can be an issue, but many people see this code and nothing was noted before or after". AND THANKS VERY MUCH i'LL INFORM YOU ON PROGRESS.

:SNSign:

check engine light on update

all problems solved thanks HISSIN50,heres what happened before posting this thread, car was surging at idle and drive, and the check engine light appeared.i had codes listed above plus codes #121,122 @123. i tested the tps it failed test so i replaced the tps and adjusted volts to .98. i cleared codes and drove the check engine light reappeared i pulled codes and recieved codes listed above#177&543 then posted this thread and with info. recieved from HISSIN50 today i tested both ho2s the right failed the resistance test the left passed. the code that was displayed was left side running lean. why is this?knowing i needed at least 1 new h02 sensor i stopped test, removed both sensors and replaced both sensors, i like to replace items like this in pairs.drove and it ran great(no codes appeared) it just idled a little rough so i rechecked tps voltage it read .96 i readjusted to .99 put her back on the road and it drove even better and idled nice, no surging issues at all and no codes. oh ya i cleaned the maf sensor the other day too. why do ya'll think code 543 was displayed? thanks again HISSIN50!
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