would changing a fuel filter or air filter help any of this issue? Also if i cut out the connector and just hard wired the oxygen sensor in would it increase the voltage. I know there would be less resistance over the harness, in-turn increasing the voltage?

 

No that will not help. Its a simple circuit. Power goes from the RCM through the heater and up to the ecu. That's it! You either have a bad connection on one of the wires a bad heater or a cooked ecu. You need to compare your voltages to the known good sensor sitting right next to the bad one. Now do it!

 

I agree with Tuna here.
Find the problem first then fix it. Stay focused on it being an electrical problem.

If you just cut the connector off at the sensor you will need to make a weather tight connection to fix it or you will be right back with more problems AND there is no guarantee that it will fix your problem that you have now. Be aware that you cannot just solder the wires together either. The sensor has steel wires that are difficult to solder to.

 

ok so i check voltage on other harness.

First sensor measured 10.45v second measured 10.47.

I measured the voltage sing the obdII and I was getting 0.455v and 0.455-0.456. Seems like the voltage is close to the same. I guess im gonna try switching the sensors areound and see what happens.

If I kept the sensor plugged in and removed it from my exhaust pipe and plugged the pipe with a bolt would this eliminate my cel? I wanted to test to see if this would eliminate the cel and then I could also check to see if the sensor was actually heating up?? Let me know if this would be a good idea? At least then I would know if the sensor heater is working.

 

I'd like to see the voltage at the fuse. It's F2 on the Relay Control Module which is the second fuse back from the front of the car and should be a 15A fuse. With the key on and the engine off measure the battery voltage and then the fuse, they should be almost the same. Looking at the top of the fuse there are two little slits that you can put your meter lead on to measure the voltage at the fuse. Measure both sides and the battery and let me know what you get.
If you are looking at the 2004 service manual, the fuse layout is wrong on page 8W-10-6. It's labeled as F5 there, the 2005 SRT service manual has it labeled correctly
The reason I want to know this is that there should be almost no drop in voltage at the fuse, or at the sensor for that matter and since there is low voltage to all sensors we need to find and fix this. It's possible that this sensor is more susceptible to low voltage than the other 3 so it is the only one faulting right now. if the voltage at the fuse is low then suspect the RCM.

 

Very good, now just to rule out a bad connection getting back to the ecu, ohm out the wire from pin 2 disconnected from the sensor up to connector C5 pin 1 on the pcm. Should be less than one ohm. Brown with dark green sripe.

 

Agreed bad contacts on the engine control relay maybe.

 

Ok so voltage measurements on the RCM

when running engine, battery voltage is 14.53v

I pulled fuse outta F2 and took measurements right in the fuse ports with engine running

F2 - 13.85 - 14.0V measurements jump when running engine
F1 - 14.32V
F6 - No voltage measurement
F5 - 14.41V
F3 - engaged the fan when i removed the fuse

I could not get a voltage measurement at F6?

 

voltage measurement at F2 with the key forward and car turned off

battery voltage 12.09V

F2 with the fuse removed measuring directly at the port 8.42 voltage
noticeable voltage drop

 

Ok so I just ordered a new relay control module due to time constraints. I am hoping this to be the issue?

I have also replaced so far
4 oxygen sensors - 3 Herco sensors, 1 OEM sensor
1 crank shaft position sensor
1 secondary air injection pump
dismantled and cleaned egr valves
cleaned all connection on 02 sensors and connections on RCM

 

Don't remove the fuse to take the reading. I think you might have measured the voltage on the wrong side of the fuse socket. You can measure the voltage at the fuse by placing your probe on the small slot on either side of the fuse value text [ - 15A - ] see the two dashes?

 

I tried to measure voltage on the slots of the fuse and did not get any voltage reading. I tried with the key forward with car off and with key forward and car running. I also measured voltage over other fuses and could not get a reading?

 

See this test would have completed testing of the wiring prior to spending money on the RCM. Now you still have not eliminated another possible problem.good luck I hope it is the RCM.