need help with o2 sensor wires

[Orangedsm95]

Im trying to test my o2 sensor and im not sure what all the wire voltage should be. Ive done some searching and I know the wires on the harness side are
red - power - 12 volts
yellow - heater - .3 to .4 volts?
black- signal ground
white - signal - .1 to 1.0 volt?
How many volts should the heater wire be putting out? Also on good sensor what should the signal volts be?
Now for the sensor side
2 blacks wires - heater wires - about 12 ohms?
blue - signal
white - signal ground
When i checked the continuity of the heater wires i saw 18-22 ohms. How many ohms should they be?

 

[gofer]

(1) Blue - Signal wire
(2) Black - Heater wires
(1) White - Ground wire

First start the car and let it get to full operating temp (180* +) so the o2 sensor is cycling like it should, this allows the car to enter closed loop. The (2) black wires are for the heater, the blue wire is the signal, and the white wire is the ground. You are looking for voltage on the blue (on the signal wire) to cycle above and below 0.45 volts. If you see it cycling and its moving from 0.2 to 0.7 volts your done testing the sensor, its good. If its not cycling and the voltage your seeing appears to be "stuck" then it might not be warmed up yet, run the engine above 2k RPM for about 30 seconds and check it again. If it appears to be "stuck" and not cycling after doing this more often than not you have a bad o2 sensor. One last thing you can do to ensure the sensor is actually stuck is create a vacuum leak at the IM (intake manifold) by removing a vacuum line. This should create a lean condition and force the o2 sensor to cycle below 0.5 to 0.1 volts.

Since the sensor must be installed and plugged into the wiring harness and ECU you'll probable have to find a set of sharp DMM (digital multimeter) leads to stab through the wire insulation to test the voltage accurately. The front o2 sensor wires go over the top of the heat shield so when your testing it be sure your DMM leads aren't going to go into your P/S or alternator belts when you start the car. The rear o2 sensor is easily accessed by removing your driverside seat and kickpanel, then pulling back the carpet until you see where the sensor is fed through a hole in the bottom of the car.

 

[Orangedsm95]

(1) Blue - Signal wire
(2) Black - Heater wires
(1) White - Ground wire

First start the car and let it get to full operating temp (180* +) so the o2 sensor is cycling like it should, this allows the car to enter closed loop. The (2) black wires are for the heater, the blue wire is the signal, and the white wire is the ground. You are looking for voltage on the blue (on the signal wire) to cycle above and below 0.45 volts. If you see it cycling and its moving from 0.2 to 0.7 volts your done testing the sensor, its good. If its not cycling and the voltage your seeing appears to be "stuck" then it might not be warmed up yet, run the engine above 2k RPM for about 30 seconds and check it again. If it appears to be "stuck" and not cycling after doing this more often than not you have a bad o2 sensor. One last thing you can do to ensure the sensor is actually stuck is create a vacuum leak at the IM (intake manifold) by removing a vacuum line. This should create a lean condition and force the o2 sensor to cycle below 0.5 to 0.1 volts.

Since the sensor must be installed and plugged into the wiring harness and ECU you'll probable have to find a set of sharp DMM (digital multimeter) leads to stab through the wire insulation to test the voltage accurately. The front o2 sensor wires go over the top of the heat shield so when your testing it be sure your DMM leads aren't going to go into your P/S or alternator belts when you start the car. The rear o2 sensor is easily accessed by removing your driverside seat and kickpanel, then pulling back the carpet until you see where the sensor is fed through a hole in the bottom of the car.

When the sensor is cycling im seeing .1 to 1.0 volts. Is that ok? Im getting a code for a heater circuit malfuction on the front sensor (PO135). Do u know how many volts the heater wire on the harness side should be putting out and on the sensor side do u know what the continuity should be between the 2 heater wires?

 

[gofer]

When the sensor is cycling im seeing .1 to 1.0 volts. Is that ok? Im getting a code for a heater circuit malfuction on the front sensor (PO135). Do u know how many volts the heater wire on the harness side should be putting out and on the sensor side do u know what the continuity should be between the 2 heater wires?

As far as I know checking continuity between the wires doesn't tell you anything, maybe someone can jump in here and correct me. The heater wire I would think be getting 12v but I'm not for certain.
If your throwing a CEL but you just verified that the front o2 sensor is cycling like it should (.1 to 1v) then clear the code and see if it pops again. Your o2 sensor might have gotten carbon build up and was stuck for a drive cycle and threw the code randomly or the sensor is going bad...

 

[Orangedsm95]

As far as I know checking continuity between the wires doesn't tell you anything, maybe someone can jump in here and correct me. The heater wire I would think be getting 12v but I'm not for certain.
If your throwing a CEL but you just verified that the front o2 sensor is cycling like it should (.1 to 1v) then clear the code and see if it pops again. Your o2 sensor might have gotten carbon build up and was stuck for a drive cycle and threw the code randomly or the sensor is going bad...

I cleared the code with the scanner and it came back within a day. I pulled the sensor and it looks to be in pretty good shape. I guess the sensor must be on its way out because the a-f ratios are real erratic. Would a bad MDP sensor cause the car to have erratic a-f ratios? The car also is throwing a code for a bad MDP sensor (p1400).

Please help im lost here.

 

[Orangedsm95]

I went and had the car put on the engine scanner and the code for the o2 sensor is no longer coming up. But the MDP sensor code p1400 is stilling coming up, along with p0443 which i believe is coming up because the emissions are deleted.

 

[gofer]

Replace the MDP sensor, to my knowledge that would be the only thing possible that would throw that CEL.

 

[Orangedsm95]

I did a little more research and found out that the p0443 code is for the evaporative emissions purge valve circuit. Where is that located?

I plugged the purge solenoid back in and cleared the codes. I drove the car today and the cel came back on. Plugged the scanner in, these codes came up P0170 fuel trim malfunction and P1400 which it has been coming up. The fuel trim code would explain the erratic a-f ratios. Now where to start with that .