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P0136 - Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
Posted 23 January 2011 - 04:13 PM
So, folks, talk to me about what to do. Is this the first or second cat? Should I check the wires going from that cat up to the wiring harness? Should I pull out the O2 sensor and clean it off? Your ideas are welcome.
Posted 23 January 2011 - 04:34 PM
Posted 23 January 2011 - 05:01 PM
Posted 23 January 2011 - 05:02 PM
Got 235k miles. Have another cat to put on if necessary.
Posted 23 January 2011 - 05:56 PM
Probably should change it anyway.
Posted 23 January 2011 - 05:57 PM
235k on the original sensor?
Probably should change it anyway.
I am unsure as I bought the car in May 2010 with 220k on it.
So this is the SECOND cat's O2 sensor? I'll swap it out and hope that helps.
Posted 23 January 2011 - 06:00 PM
Check the wiring for the sensor before changing it. It runs up the side of the transmission. Make sure it isn't touching the pipes or rubbing against something it shouldn't be.
Posted 25 January 2011 - 02:26 PM
Posted 21 February 2011 - 12:22 AM
Posted 21 February 2011 - 02:23 AM
Alright. I replaced the O2 sensor with OE sensor last week and cleared the code. Gas mileage came back. All seemed to be well until I filled up again and the CEL came back on, complaining of the same code.
Disconnect the neg batt lead and press the brake pedal to drain any residual current, then re-connect the neg batt lead or skip these steps and clear the code with your scantool and see how long before the CEL re-appears. If it re-appears quickly, check the circuit wiring for shorts. If no shorts are found, check for exhaust leaks before the secondary bank 1 O2 sensor. A leak before the O2 sensor could cause the sensor to read too lean which could trigger a "low voltage" code.
My best guess is that you have an exhaust leak before the CEL throwing sensor.
Posted 21 February 2011 - 03:25 AM
Posted 21 February 2011 - 10:21 AM
Quick question- how many O2 sensors are there per cat?
Posted 21 February 2011 - 10:29 AM
typically in the late 90s there is one o2 before the cats and one after.
Posted 21 February 2011 - 10:31 AM
I had a muffler shop replace this cat over the summer with a brand new Wagner cat.
Posted 21 February 2011 - 10:35 AM
Posted 21 February 2011 - 10:36 AM
That eliminates a bad CAT then. Did you verify the wiring between the sensor and the ECU is ok before replacing the sensor?
How might I do that? Checking voltage?
Posted 21 February 2011 - 10:40 AM
Posted 21 February 2011 - 10:49 AM
Posted 21 February 2011 - 12:36 PM
Posted 21 February 2011 - 12:40 PM
Posted 21 February 2011 - 01:37 PM
Posted 21 February 2011 - 02:54 PM
example if this is your wire:
o2 sensor here:X--x----------x-------------[clip]-------------------------------------X < ecu
one of the lowercase x's = one of your voltmeter leads
02:X-----------x--------------x-[clip]--------------------------------------X < ecu
then keep moving down the wire and when you get to a plug in or clip be sure to check it with one lead on each side of the clip and if you get more than a half volt then replace that section of the wire or that particular clip. the goal for this test is .5v or less. say for example you test the clip and you get a 2v reading on your voltmeter that means your sensor would only be receiving 10v instead of 12v. keep in mind that the voltage drops are cumulative so if you have two or three spots that average 1.5v then that is 3 or 4.5v less for the circuit to receive. remember THE CIRCUIT HAS TO BE POWERED for this test to work. LOL you wouldn't believe how many times i would start a voltage drop test with the power turned off only to realize it and then start over.
not trying to insult anyones intelligence here, it's just confusing (at least for me) without a visual reference of some sort.
if anyone knows this technique better or if i forgot something correct me so i can learn it too.
Edited by SubaruAlliance, 21 February 2011 - 03:02 PM.
Posted 21 February 2011 - 04:43 PM
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