Scanner how-to

[5337]

I bought a scanner to help find a problem with my Jeep and now have retrieved 2 codes from my Ranger.
The codes are po171 and po174 lean bank 1 and bank 2.
I have cleaned the MAF sensor and checked for vac leaks but the codes keep coming back after resetting

I don't really know how to use the scanner the way it was intended to be used but I read in a previous post that you can check the O2 sensors with it

Could someone explain how to do this or point me in the right direction.

My truck is a 2000 XLT 4.0 4x4 A/T and the scanner is a ACTRON CP9145

Thanks in advance,
Tim

 

[5337]

I got a reading from the scanner yesterday with truck running for the O2 sensors.
The first reading was O2S22 (V) -1.2 - 8.3.
The second reading was O2S12 (V) 0.620 - 0.645
The third reading was O2S21 (V) -0.70 - 0.785

Could someone tell me what this means?
Are these the individual readings for the O2 sensors and how do I tell which is which?

Thanks for the help,
Tim

 

[jmg8550]

If your first reading was really 1.2 to 8.2 v, you have a serious problem. Like a dead short to power. as far as the other o2 sensors, you really have to watch how the o2 sensors switch(going from around .1v to.9v). the front sensors should do that fairly fast. the rears are gonna react fairly slow. this is normal as it also monitors your catalytic converter efficiancy.

 

[5337]

Thanks jmg,

These readings were from the lowest to the highest on each sensor. They kept alternating and I documented the lowest and the highest of the readings.

It would read a negative number then jump to positive numbers and back and forth.

I guess I'll have to take to the shop and have them check it out.

Thanks