Exhaust 99 V6, P0135 Code

austin3749

Member
Nov 10, 2018
24
2
13
19
Pennsylvania
I have an engine code for P0135. Sensor 1, Bank 1. I know that sensor 1 is upstream/front, but which side is Sensor 1? I’m not entirely sure. I ordered a new O2 sensor from AM to replace it. And also, is it before or on the catalytic converter?

Thanks for any answers. I definitely want to get to the point where I’ll work on my car a lot more.
 
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wmburns

SN Certified Technician
Aug 14, 2009
5,360
417
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Houston Texas
bank x sensor y

For a Ford bank 1 is on the right side (from the car's point of view). Bank 2 on the driver's side.

Sensor 1 is before cat. Sensor 2 is after cat.

Soooooooooo bank 1 sensor 1 is right hand side before cat.

Note, when ever a "circuit Malfunction" is called out it usually means that something is so wrong with the circuit that the PCM is unable to perform any real diagnostics. Think:
  • connector problem. dirty pushed corroded pins.
  • wiring problem
  • blown fuse.
  • serious bad O2 sensor.

P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
  • Short to VPWR in harness or HO2S.
  • Water in harness connector.
  • Open VPWR circuit.
  • Open GND circuit.
  • Low battery voltage.
  • Corrosion or poor mating terminals and wiring
  • Damaged HO2S heater.
  • Damaged PCM.
 

austin3749

Member
Nov 10, 2018
24
2
13
19
Pennsylvania
bank x sensor y

For a Ford bank 1 is on the right side (from the car's point of view). Bank 2 on the driver's side.

Sensor 1 is before cat. Sensor 2 is after cat.

Soooooooooo bank 1 sensor 1 is right hand side before cat.

Note, when ever a "circuit Malfunction" is called out it usually means that something is so wrong with the circuit that the PCM is unable to perform any real diagnostics. Think:
  • connector problem. dirty pushed corroded pins.
  • wiring problem
  • blown fuse.
  • serious bad O2 sensor.

P0135 - HO2S Sensor Circuit Malfunction (HO2S-11)
  • Short to VPWR in harness or HO2S.
  • Water in harness connector.
  • Open VPWR circuit.
  • Open GND circuit.
  • Low battery voltage.
  • Corrosion or poor mating terminals and wiring
  • Damaged HO2S heater.
  • Damaged PCM.
Alright, that sounds good, or at least good to know. In most cases, I would assume replacing the sensor entirely would solve the issue unless it was due to water in the harness or a fuse issue, correct? The sensor I ordered from AM requires reusing the harness and all so I guess I have to cut some wires. Hopefully it isn’t much for me, I got an aftermarket radio working with the wires so hopefully this works.