1998 GMC Jimmy service codes

Never let AutoZone tell you what the code means. They don't know. They just know what the code description is.

P0147 indicates something is wrong with the HO2S Heater Circuit. Check wiring and connections to Bank 1 Sensor 3 heater circuit.

P0300 is a misfire detected so it is possible the coil is bad, but check all other typical "misfire" components. But, fix the P0147 BEFORE diagnosing the P0300. ;)

P1133 relates to the HO2S not working properly, repair the P0147 and this will most likely go away.

Steve

They did say it needs a tune up, and I knew that was not the case. Maybe this is a silly question but what/where is the Bank 1 Sensor 3 heater circuit?

As Shep said, its the one after the cat.

Thanks guys. Picked up a new O2, and found I needed a special socket for it. I changed the one that is behind the cat. It took allot to get it out. I ran the engine for a while to warm it up and used a torch on it. It came out hard all the way. When I got it out the treads were GONE. I tried to get the new one to go it but no luck. Took it to the local muffler shop and they installed a new port.

I then took it to A Z and had them clear the codes. Drove it for about 5 miles and no service engine light. Fuel mileage is up. Time will tell.

O2 sensor behind the Cat did not clear up the problem Service light came back on. Will check the codes tomorrow

post catalytic oxygen sensor is not used for fuel trim,

ended up the one before the cat.

Bank 1 Sensor 3 is the one after the cat.

I changed the one after the cat and the mileage went down to 6mpg. The problem was the one before the cat the wires got against the drive shaft and wore completely cutting two of the wires.

I know the story from the other thread, it's all about context.