joefnh
Well-Known Member
- Joined
- April 30, 2005
- Messages
- 223
- Reaction score
- 0
- City, State
- New Hampshire
- Year, Model & Trim Level
- 03 XLT
- Callsign
- KA1DGB
I have an 2003 Ford Explorer XLT 4.0L V6 that i have been using Live Link & an Xcal-2 (both latest versions of software and firmware)
When using live link to look at the O2 sensors I noted that what appeared to be the bank 2 upstream sensor not switching. After replacement & further diagnosis with an ocilloscope, I noticed that the O2 sensor was working fine.
After the Oscope test ,I checked again and Live Link still showed a very slowly switching / faulty sensor.
So at this point the O2 sensor is a known good and the wring to the PCM is also known to be good. Both signal and heater power connections.
I then went to each of the 4 O2 sensors connectors one by one, while unplugged put a 4k ohm resistor across the vpower to signal pins. All the while monitoring Live Link for signal change. I did these one O2 connector at a time noting the actual position I was testing and the results in Live Link.
By putting a 4k ohm resistor across these pins you force a .8V signal to the PCM so that you can see any changes in the signal without starting the engine (KOEO)
What I found is that Live Link was reporting the sensors positions incorrectly. For instance, the reported bank 2 upstream position was actually the bank 1 downstream position.
The question I have is do I believe Live Link or Ford.
It does not appear that any of the wire harness has been modified from the factory placement.
Any help would be greatly appreciated.
--Joe
Manchester, NH
When using live link to look at the O2 sensors I noted that what appeared to be the bank 2 upstream sensor not switching. After replacement & further diagnosis with an ocilloscope, I noticed that the O2 sensor was working fine.
After the Oscope test ,I checked again and Live Link still showed a very slowly switching / faulty sensor.
So at this point the O2 sensor is a known good and the wring to the PCM is also known to be good. Both signal and heater power connections.
I then went to each of the 4 O2 sensors connectors one by one, while unplugged put a 4k ohm resistor across the vpower to signal pins. All the while monitoring Live Link for signal change. I did these one O2 connector at a time noting the actual position I was testing and the results in Live Link.
By putting a 4k ohm resistor across these pins you force a .8V signal to the PCM so that you can see any changes in the signal without starting the engine (KOEO)
What I found is that Live Link was reporting the sensors positions incorrectly. For instance, the reported bank 2 upstream position was actually the bank 1 downstream position.
The question I have is do I believe Live Link or Ford.
It does not appear that any of the wire harness has been modified from the factory placement.
Any help would be greatly appreciated.
--Joe
Manchester, NH
