1998 Blazer Codes

P0135 O2 sensor heater malfunction (Bank 1 Sensor 1)
P0147 " " (Bank 1 Sensor 3)
P0155 " " (Bank 2 Sensor 1)

Are the codes, does this mean just replace the O2 sensor or sensors?

How many are there and where are they at?

Also, Ive got a code reader so if anybody lives in the Albany/Saratoga Springs area I can read your codes for you.

With 3 o2 sensors giving heater element codes, I'd first suspect a circuit issue that supplies the voltage to the sensor's heater circuit. The same circuit supplies those 3 o2 sensors for the heater element side.

Have you checked the underhood fuse block? There is a 15Amp O2 sensor fuse that feeds those 3 o2 sensors for the heater element.

If the fuse is OK and you are seeing 12volts on the pink wires at the 02 sensors with the key in the Run position, then check the black wires (grounds).

How many miles do you have?

With 3 o2 sensors giving heater element codes, I'd first suspect a circuit issue that supplies the voltage to the sensor's heater circuit. The same circuit supplies those 3 o2 sensors for the heater element side.

Have you checked the underhood fuse block? There is a 15Amp O2 sensor fuse that feeds those 3 o2 sensors for the heater element.

If the fuse is OK and you are seeing 12volts on the pink wires at the 02 sensors with the key in the Run position, then check the black wires (grounds).

How many miles do you have?

~95000 miles

I'll check the fuse and then check the wires for power and what not. Where exactly are the sensors?

Thanks
Billy

I don't have any pictures to show, but if you get under the vehicle, you will see an o2 sensor on each side of the engine, under the vehicle, near transmision level. They stick out of the exhaust pipe. Hard to miss. There is also one behind the catalytic converter, which monitors the operation of the catalytic converter.

I don't have any pictures to show, but if you get under the vehicle, you will see an o2 sensor on each side of the engine, under the vehicle, near transmision level. They stick out of the exhaust pipe. Hard to miss. There is also one behind the catalytic converter, which monitors the operation of the catalytic converter.

Fuse was bad, replaced it, watched it blow, took a resistance to ground reading very low, so something is grounded, I guess that I'll just have to unplug one sensor at a time to try to find it.