I was getting an intermittent generic emissions DTC (I forget which code), so I decided to replace oxygen sensors to see if that would clear it up.
Yes, I had already checked vacuum hoses and fuel cap.
I was already planning to replace the plugs and wires, so I figured that I would knock out the oxygen sensors while I was at it. I did the sensors first, so that I would not risk damaging a new plug wires while wrestling with the upstream sensor.
I have seen most of the oxygen sensor related threads on here since doing the job. I should have checked here first. So I guess that the first mistake was getting the Bosch sensors at Autozone. I am not convinced yet that that is the problem...yet. I saw the thread(s) about the change in sensors during production in 2005. My T&C Touring 3.8L, was manufactured April 2005, a month AFTER the dates listed in TSB 05005. So that should not be the issue. I have triple checked that Autozone did hand me the correct sensors.
As the title indicates, I am getting codes for Heater Failure and Heater Circuit High Voltage on the upstream sensor.
With the engine off, I put a DVM across each of the four contacts at the end of the sensor harness and checked resistance. I figured maybe I should see something across the heater contact, or maybe not. Anyway, all combinations of connections across all four wires showed infinite resistance. Maybe that is normal, I do not know.
Instead of checking voltage with the DVM while the sensor was in circuit, I used my handy dandy Autera Dynoscan / OBD II, which includes the oxygen sensor module. with the engine idling, it shows the upstream sensor reporting ~ 1v. If I rev the engine, the voltage drops accordingly and then climbs back up over 1v when I let off the accelerator. FWIW, I also monitored the downstream sensor at the same time (split screen). While it varied some with revving, it stayed in the .6v to .8v neighborhood.
So it *seems* to be working, but I say that not really knowing what the actual voltage range should be.
So at this point, any assistance is appreciated.
Yes the engine is running a little rough, although not significantly. I notice it, since I drive it everyday. Someone else might not notice it. I only notice it when accelerating from a stop.
So far, the mileage meter in the overhead console is still showing 20.6 during my daily commute, even though I did a reset on it a few days ago. That is about where it usually sits.
Thanks
Dean
Yes, I had already checked vacuum hoses and fuel cap.
I was already planning to replace the plugs and wires, so I figured that I would knock out the oxygen sensors while I was at it. I did the sensors first, so that I would not risk damaging a new plug wires while wrestling with the upstream sensor.
I have seen most of the oxygen sensor related threads on here since doing the job. I should have checked here first. So I guess that the first mistake was getting the Bosch sensors at Autozone. I am not convinced yet that that is the problem...yet. I saw the thread(s) about the change in sensors during production in 2005. My T&C Touring 3.8L, was manufactured April 2005, a month AFTER the dates listed in TSB 05005. So that should not be the issue. I have triple checked that Autozone did hand me the correct sensors.
As the title indicates, I am getting codes for Heater Failure and Heater Circuit High Voltage on the upstream sensor.
With the engine off, I put a DVM across each of the four contacts at the end of the sensor harness and checked resistance. I figured maybe I should see something across the heater contact, or maybe not. Anyway, all combinations of connections across all four wires showed infinite resistance. Maybe that is normal, I do not know.
Instead of checking voltage with the DVM while the sensor was in circuit, I used my handy dandy Autera Dynoscan / OBD II, which includes the oxygen sensor module. with the engine idling, it shows the upstream sensor reporting ~ 1v. If I rev the engine, the voltage drops accordingly and then climbs back up over 1v when I let off the accelerator. FWIW, I also monitored the downstream sensor at the same time (split screen). While it varied some with revving, it stayed in the .6v to .8v neighborhood.
So it *seems* to be working, but I say that not really knowing what the actual voltage range should be.
So at this point, any assistance is appreciated.
Yes the engine is running a little rough, although not significantly. I notice it, since I drive it everyday. Someone else might not notice it. I only notice it when accelerating from a stop.
So far, the mileage meter in the overhead console is still showing 20.6 during my daily commute, even though I did a reset on it a few days ago. That is about where it usually sits.
Thanks
Dean