Originally Posted by McIvor dbl 07
Ok, so I found out why the O2 sensor read may have been going off. The mechanic that installed it didn't tighten it all of the way! That guy may not have a job tomorrow... Anyways so after I fixed that, I still got the reads for bank 1 sensor 1, bank 1 sensor 2, and another EVAP leak. We ran the smoke through the lines and fixed all of the leaks last time. I'm not sure what else to do besides keep throwing new parts into it until the check engine light goes off. The error codes that came up are P1443, P0141, and P0135. Any suggestions?
I don’t think one of the sensors not being fully tightened would cause these problems.
To start you’ll need to do some functional tests. So lets start with the O2 heater circuit first. At each sensor connector (chassis harness side) you’ll find four wires. The ones you’ll be looking for are as follows:
Sensor 1 Bank 1: Light Blue with Orange stripe (connector pin 1 engine side of harness Power supply). The other is Red with White stripe (connector pin 2 engine side of harness to PCM pin 93 ground control).
Sensor 2 Bank 1: Light Blue with Orange stripe (Power supply). The other is White with Black stripe (PCM pin 95 ground control).
Using a DVM set to read 12V and both connectors disconnected turn the ignition switch to the run position but do not start the engine.
Next, insert the red probe from your DVM to sensor 1 bank 1 connector pin 1. Connect the black probe to a known good ground. You should read 12V (or battery Voltage). Do the same thing at sensor 2 bank 1 connector pin 1. Again you should read 12V.
If you don’t read 12V at either connector you’ll need to check the HEGO fuse 20 (15AMP). If you only read 12V at one, you’ll need to trace the wiring to find the open circuit and repair it.
Next you’ll need to check the ground side. Set your DVM to read Ohms. Insert one probe in sensor 1 bank 1 connector pin 2 and the other to a known good ground. You should see a reading of less than 2 ohms (note some systems pulse the ground circuit for duty cycle so you may see the meter jumping between 1 ohm to infinity. This is normal). Someone else may have more definitive information on this aspect of the ground circuit operation.
Next do the same at sensor 2 bank 1 connector pin 2.
If your meter indicates no reading (infinity) you’ll need to trace the wiring back to the PCM looking for an open circuit.
Next,you'll need to test the actual sensors heater element in the O2 sensor. Utilizing the connector from the sensors pigtail, identify the corresponding pins 1 & 2. Using your DVM set to read Ohms, insert one probe in pin 1 and the other in pin 2. Your meter should read between 2 – 2.5 ohms. If lower than 1.6 ohms or greater than 2.8 ohms, you’ll need to replace the sensor.
Also, if you have a scan tool, what is your engine coolant temperature sensor reading (not the temp gauge on dash) when the check engine light comes on?