o2 sensor

[wpony1]

HI I drove the van over to the parts store to see if the service engine light that was on had any thing to do with the transmision jerk going into 1st from nuetral and it shows o2 sensor on bank 2 but the engine runs great no miss at all do you think it is a false light or can it be a bad sensor and run good anyway ,
Thanks George

[inafogg]

clear the code & see if it resets

[wiswind]

When having them read the codes, ASK for the actual numeric code.
They normally don't give it to you unless you ask, as it makes no sense to most people.
HOWEVER, you can more accurately troubleshoot your problem with this code.
There are a number of codes that are "oxygen sensor".

The most common code is P0171 and P0174, which is a lean code (one is for bank 1 and the other is for bank 2)
These codes mean that the oxygen sensor is returning a reading that is indicating a lean condition.
The MOST likely cause of this is a vaccum leak.
The LEAST likely cause of this is a defective oxygen sensor.

This can also be caused by a dirty fuel injector(s), and the PCM trying to compensate for this, which is difficult because the injectors are no longer spraying the same amount of fuel in when activated.
For this, I would put a can of Berryman's B-12 Chemtool into a tank of gasoline to clean the fuel injectors up.
This is a good fall tuneup item to get ready for winter.

[wpony1]

the code is P0161

[wiswind]

P0161 is a malfunction in the HEATER circuit for the downstream oxygen sensor for bank #2, which is the FRONT bank of cylinders.

This is the sensor that is AFTER the catalytic converters.

I would check the wiring....making sure that it is not against the exhaust system at any point. The wires to the downstream sensors are held up off the exhaust system, but could have fallen down.
Also, unplug and check the contacts inside the connector that the wires from the sensor go into....and plug into the vehicle wiring.

It is possible that the sensor has failed, but check these things just to be sure.

I prefer to change the upstream sensors as a pair, as then you have matched switching speeds / charactoristics.
However, this is NOT important for the downstream sensors, as they switch at a much slower speed, and are not used at all for fuel trim or other engine controls.
The downstream sensors are used ONLY to monitor the catalytic converters to make sure that they are working correctly.

[wpony1]

Hi could that have any thing to do with the trans not shifting into 1ST when it warms up? I have a friend coming down today to flusg out the trans and change the filter. Thanks for all your help George

[wiswind]

I do not see how the oxygen sensor would cause that problem with the transmission.

Fluid change, and the Transmission Range Sensor (TRS), aka "neutral safety switch" are the 2 things that I would try for the transmission problem.

I have step by step pictures of the transmission fluid and filter change on my '96 posted in the pictures that the link in my signature takes you to.

Mobil 1 is now Mercon V specified and would be a easy to find fluid that would be an excellent choice for all years (including former Mercon years).