Mechanics

CHECK ENGINE LIGHT ON WITH IGN. ON AND WHEN ENGINE RUNNING

2003 Chevrolet Avalanche • 220 miles

Have replaced all four O2 sensors and vehicle had new plugs and wires fitted just before I purchased it(last week) Am reading p0300 and p0155 on OBD2 reader. Where and how do you check for voltage problems on sensors?
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Billy Adams
November 10, 2011.




I would suggest checking voltage variation while the vehicle is running and with a live scanner. That way you can see exactly what the sensors are doing.
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You cant always rely on those lites I dont car what anyone says! I have a 06 baja if I go up a steep hill up or down my lite comes on & theres nothing wrong with it! Sometimes when you fuel up if you dont click the gas cap 3 times the lite will come on & thats most cars & trucks then when you run the codes itll say something related 2 emissions when its just a gas cap! If you unhook your battery 4 maybe 30 to 45 seconds it will clear its brain & reset the lite wont hurt anything done it to many times try & see some say it will hurt the computer but if that was fact if you ever had a dead battery then it would hurt the computer dont make sense! Try it it works

Tiny
BILLYBOB
Nov 10, 2011.
BILLYBOB--I CAN AGREE ON SOME OF YOUR THINKING BUT NOT ALL!

1ST I CONSIDER AN IDIOT LIGHT A "LOW FUEL"---"TEMPERATURE"---"OIL PRESSURE" LIGHT. THE THINKING ON THIS WAS GAUGES WERE PRETTY MUCH A STANDARD. PEOPLE WERE/ ARE SO ACCUSTOMED TO THEM THEY FAIL TO LOOK AT THEM----(ACTUALLY FAIL TO SEE WHAT THEY ARE SAYING!)

INTRODUCE THE "IDIOT LIGHT". SOMETHING DIFFERENT, SOMETHING EYE CATCHING. BAD THING IS NO "REAL TIME" INFO IS DISPLAYEDCAN I DRIVE THIS OVERHEATED RIG ANOTHER MILE. IS MY OIL PRESSURE "ZERO" OR "15 PSI". THE BEST THING AS FAR AS MECHANICALS THAT "SHOULD HAPPEN" IS THE VEHICLE SHUT DOWN, UNTIL IT IS REPAIRED! NOT GOOD, SOMEONE SOMEWHERE WOULD BE IN MASSIVE TRAFFIC AND GET KILLED WHEN THEIR VEHICLE SUDDENLY STOPPED. IN A PERFECT WORLD, NO ONE WOULD FOLLOW THAT CLOSE, ALL WOULD GO WELL!

AS FAR AS THE CHECK ENGINE LIGHT.I AGREE SOME OF THE INFO IT REFERS TO IS "JUNK", AND DOES NOT AFFECT DRIVABILITY

A LOT OF IT IS NOT!

YOUR CAR RUNS OPEN LOOP AND CLOSED LOOP WITH A COMPUTER

"OPEN" IS WHEN THE CAR GETS OUTSIDE INFO, LIKE FROM "MAP" OR "O2s", THIS IS REAL-TIME RUN EFFICIENTLY INFO

"CLOSED" IS WHEN A SENSOR HAS NOT COME ON-LINE YET, LIKE WHEN YOU 1ST CRANK UP, THE O2s ARE COLD, AND CANNOT SEND INFO TO THE COMPUTER. TO MAKE IT RUN, THE COMPUTER IS SET UP WITH FACTORY "VALUES" (FALSE SENSOR READINGS) JUST TO MAKE IT "RUN", UNTIL ALL OF THE SENSORS START WORKING. IT IS NOT RUNNING EFFICIENTLY! MILEAGE AND PERFORMANCE SUFFER!

IF YOU HAVE DISABLED/ HAVE DEFECTIVE SENSORS, LIKE DOWNSTREAM O2s, YOU MIGHT NEVER BE RUNNING IN OPEN LOOP!

PERFORMANCE AND MPG WILL SUFFER. MAYBE TERRIBLY!

MY SISTER KEPT GETTING A CODE ABOUT HER CATALYTIC CONVERTER, IT WAS REPLACED. SHE WAS TOLD BY SOMEONE ELSE, THE CODE WAS SORTA UNIMPORTANT, SHE SHOULD HAVE DISREGARDED IT. A FEW MONTHS LATER THE LIGHT CAME BACK ON. SHE DISREGARDED IT.(YES, IGNORANT!) SHE DISREGARDED IT!

I ASKED HER IF SHE WANTED ME TO SCAN IT. SHE INSISTED IT WAS THE SAME THING AS BEFORE (NOT ONE OF 100 MORE POSSIBILITIES!)

BEING IGNORANT WHEN HER MPG GOT CUT IN HALF, SHE ATTRIBUTED THAT, TO HER VEHICLE BEING OVER 5 YEARS OLD. IN REALITY SHE HAD A BAD O2 SENSOR, I CAUGHT IT WHEN MY CURIOUS BROTHER-IN-LAW DROVE IT OVER ONE DAY AND SAW ME SCANNING ANOTHER CAR.

JUST SO YOU SEE MY STAND ON THE WHOLE DEAL, THERE ARE A LOT OF OLDER VEHICLES--NOW CONSIDERED "CLASSIC"----THAT YOU CAN RESTORE AND LEGALLY DRIVE.W/ CARBURETORS!

COMPUTER. YEAH! THE ONE BEHIND THE WHEEL. WHO CAN READ GAUGES, WHO REMEMBERS TO TURN THE LIGHTS ON AND OFF AT THE PROPER TIMES, CAN INSTRUCT THE PASSENGER HOW TO ADJUST THE MIRROR ON THAT SIDE, SERVICES THE VEHICLE REGULARLY, THE LIST GOES ON!

THE COOL THING ABOUT MY WAY OF THINKING IS, A VEHICLE RESTORED LIKE NEW IS PROBABLY HALF AS MUCH $$$ AS A NEW ONE, SYSTEMS ARE SIMPLE, INEXPENSIVE TO REPAIR. BUT YES, I LIVE IN A FANTASY WORLD. OTHERS ARE WELCOME THERE!

BUT IF YOU ARE ONE OF THOSE WHO CHOSE THE "CYBER RIG". BETTER KEEP IT UP, THEY WAY THE "CYBER ENGINEERS" WANT YOU TO. FOR MPG, SAFETY, AND TO BE "GREEN"

AS MUCH AS I HATE CHANGE, AND I MUST ADAPT (MY WIFE DRIVES A "CYBER RIG"!)

THE DARN CHECK ENGINE LIGHT HAS ITS PLACE AND IS IMPORTANT----LOOKS LIKE THEY WOULD MAKE THE DARN THING DISPLAY POSSIBLE "FIXES" ON A DASH SCREEN, INSTEAD OF NUMBER CODES, USING A PORTABLE SCANNER.I'M GONNA SUGGEST THE CELL PHONE FREAKS, GET INVOLVED WITH THE AUTO INDUSTRY

THE MEDIC

Tiny
CJ MEDEVAC
Nov 11, 2011.

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