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Hello Paul Good day, I am facing a rather hectic situation with my car, its throwing up a P0130 code and there is no activity from the HO2S1 , i swapped it with a new one still the same. O2 sensor 2 is showing activity but , when i unplugged the O2 sensor 2 the scanner still shows 0.1v, car runs fine but i think its not good for the engine running with the O2 sensors not working correctly. I checked the wiring harness its good. Its a 2014 Daihatsu hijet cargo (660cc) japanese kei car.
Do the other sensors have bias voltage? What voltage does the scanner show when the sensor is disconnected? Have you checked the wires for opens and shorts? Can you drive the sensors rich?
I would swap bank 1 sensor with bank 2. If you still have the code, you have a wiring issue or a fuel mixture issue. Swapping the sensors would help in figuring out if you have a bad new part, a wiring issue or a faulty sensor. If you have good power and control to the heater and good ground and signal (voltage drop), you either have a fuel mixture problem or a bad sensor in my opinion, unless the pcm is applying some weird strategy in my opinion.
Sorry for assuming that the vehicle has two banks. I am not at work where I could check Pro Demand.
To answer the question, I would say yes if both sensors are narrow band sensors and not a wideband and a narrow band sensor and if both of them are heated(4 wires). Have you try enriching the mixture to see if both sensors go rich? If no, try doing that and let us know.
Turns out , the engine is running rich, being a Toyota family product the first O2 is a A/F sensor which is reading 0v-0.07v and the second 02 is reading close to 0.9 which indicates a rich condition. But now what should i diagnose to fix the rich condition ??? MAP sensor is also reading close to 2g/sec at idle which is normal.
If the front sensor is a wideband sensor(A/F), the rear one is most likely a narrow band sensor. There were no need to swap them.
The reading of the 0- 0.07v of the A/F sensor and the 0.9v of the downstream suggest that there is an issue with the front sensor or its circuit. The pcm is adding fuel due to the low voltage from the front sensor causing the rear sensor to go rich. If you disconnect the sensor, do you see a bias voltage on the scanner? If you rev it up to warm the sensor, do you see a change in the front sensor voltage, which would suggest a heater problem?
The scanners shows heater circuit (Passed) and the O2 sensor (Failed). As far as i have the knowledge of electric circuits , i just made sure all 4 wires have continuity to the ecu and there is 12V on the heater wires. Should I check for bias voltage in millivolts for the sensor circuit on my multimeter?
For the bias voltage, unplug the sensor or just check voltage with key on.
We usually do voltage drop when checking for high resistance. You can have continuity and have high resistance. If you have checked eveything: All the circuits,connector, pin fitment, corrosion. control to the heater from the pcm, opens and shorts and no change, I really can't tell you more. We'll have to wait and see what others think
At least, do a voltage drop on the signal wire and the ground wire of the sensor.
So, I couldn't wait for tomorrow as i use the car daily and its been drinking a lot of fuel... I checked for the bias voltage (6.6mv)and checked the resistance(0.41kohms) in the o2 sensor circuit. I did it with the car switched on and o2 sensor unplugged.
The bias voltage can be checked by unplugging the sensor and looking at the voltage on the scanner.
The voltage drop should be done with the sensor plugged in. Does the vehicle have 2 banks? If yes, try swapping the front sensors.
You can use a test light to load the ground a little.
There is only one bank as it is a 3 cylinder engine...i swapped the post cat o2 with the pre cat and it works. But the O2 sensor 1 is working and maybe the engine is running rich because of some other problem??? As far as i have researched P0130 pops up when the ecu doesn't see the required voltages from the O2. Cause when I rev the engine abruptly the O2 Sensor 1 voltages goes up and comes right back down. What could be the other things that control the fueling of the car????
There is a lot of things that can cause a rich condition. Search things that can cause a rich condition and you will find a list.
Also, if you rapidly pump the brake pedal, the sensors should go lean than rich.
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