2000 Pathfinder (8/99)
SES light on. P0161 for bank 2 sensor 2. Changed bank 2 sensor and still have the code. I swapped bank 2 sensor 2 from cat to bank 2 sensor 1 ecm wire and bank 2,2 works. So I know the sensor is good. When I connect bank 2,1 to 2,2 ecm wire, bank 2,1 fails on scan. Anyway ideas how to check the 2,2 ecm wire that seems to be failing? Need to pass emissions asap.
P0161 error code help
Re: P0161 error code help
BTW this is the only error code coming up. No other codes, engine idles fine as well. But does have accel issues at highway speed of 50 mph. Under 50 or above 50 accels fine. Only loss of power at around 50 mph. Is this a cause of the p0161 code as well?
Re: P0161 error code help
That error is for the downstream (post CAT)sensor. From your description it appears you swapped out the sensor wire for the upstream sensor on bank 2. If that's what you did, that won't work. When you first changed the downstream sensor what was the manufacturer of the replacement? It's also possible that the initial problem was a short in the wire harness itself.
Re: P0161 error code help
Yes i did swap the sensor wires only to confirm the new sensor on b2s2 was working. I did check the resistance on the new b2s2 and its good. I checked the harness also and im getting 12v power to it as well. Maybe the signal wire is bad? I can see on a live scan that the b2s2 does move a smig when i press the gas but the waveform is not like its suppose to be. Not sure of original b2s2 manufacturer as im not the original owner and they had this problem as well. Any way to test the harness to check for problems? I did run through the Service manual but only shows how to check the resistance on the sensor. Could a bad fuel filter cause this?
Re: P0161 error code help
Ok so I just tested the b2s2 harness side and I do get 12v but I'm not getting ground. Tested with key on but not started and also started with the same result. Harness doesn't seem to be grounding. What could cause this?
Re: P0161 error code help
Neo2020 wrote: ↑Mon Jul 30, 2018 11:17 amOk so I just tested the b2s2 harness side and I do get 12v but I'm not getting ground. Tested with key on but not started and also started with the same result. Harness doesn't seem to be grounding. What could cause this?
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Old wiring exposed to too much heat and then contraction over more than a decade. You may have to run a new ground wire. BTW, The earlier question I asked about the manufacturer of the downstream sensor referred to the replacement you purchased - not the original one.
Re: P0161 error code help
Ok so I replaced all O2 sensors with Bosch. I am still getting a p0300 random now. Tested all O2's and they are in fact working. No ses light but keep getting random mf at highway speeds. Replaced maf also.
Re: P0161 error code help
I know this is an old post but I have an undiagnosed p0300 + p0161 issue. Did you ever figure out the cause of the p0300? In regard to the p0161 I noticed that there is a flat stranded (for lack of a better term) cable that is loose and appears to connect to the back of the catalytic converter. Is this the GND for the Bank 2 downstream O2?
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mdmellott
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'02 Pathfinder SE 3.5L AT P/4WD - Location: SF Bay Area, CA
Re: P0161 error code help
That small, braided grounding strap is just another engine to body ground to take out errant electrical noise. It's not a critical ground point but it should eventually be replaced when you have time. The O2 sensors have their own ground wire in the harness.texasqx4 wrote: ↑Wed Oct 19, 2022 8:16 pmI know this is an old post but I have an undiagnosed p0300 + p0161 issue. Did you ever figure out the cause of the p0300? In regard to the p0161 I noticed that there is a flat stranded (for lack of a better term) cable that is loose and appears to connect to the back of the catalytic converter. Is this the GND for the Bank 2 downstream O2?
There are many issues which can cause multiple cylinder misfires to get that P0300 DTC. The P0161 DTC has nothing to do with the cause of the misfire issue since that code is specifically related to trouble with a downstream O2 sensor that has no control related feedback for engine operations.
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VStar650CL
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2004 Nissan Altima 2.5 S
Re: P0161 error code help
Md is right on all counts. P0161 is usually a wiring problem if it isn't a bad sensor. It's for the sensor heater and not the sensor itself, the ECM is detecting an open or short circuit when it tries to fire up the heater. See EC-290 here for troubleshooting info:mdmellott wrote: ↑Wed Oct 19, 2022 9:21 pmThat small, braided grounding strap is just another engine to body ground to take out errant electrical noise. It's not a critical ground point but it should eventually be replaced when you have time. The O2 sensors have their own ground wire in the harness.
There are many issues which can cause multiple cylinder misfires to get that P0300 DTC. The P0161 DTC has nothing to do with the cause of the misfire issue since that code is specifically related to trouble with a downstream O2 sensor that has no control related feedback for engine operations.
https://www.nicoclub.com/service-manual ... 0%2Fec.pdf
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