Welcome Visitor! Please take a few seconds and 
Orca
Active Member
- Joined
- Jul 30, 2020
- Messages
- 141
- Reaction score
- 37
- Points
- 28
- Location
- USA
- Vehicle Year
- 2004
- Make / Model
- Ford Ranger
- Engine Type
- 4.0 V6
- Transmission
- Automatic
- 2WD / 4WD
- 4WD
In theory, lack of heater current shouldn't prevent the O2 sensors from eventually warming up enough to allow closed-loop operation, so it's not the most urgent of problems, IMHO.
Having said that, it's always wise to check for any Diagnostic Trouble Codes (DTCs), both 'stored' and 'pending', as reported by Torque or FORScan. Scanning the thread, I see no mention of "codes", so if you haven't checked yet, please consider doing so now.
In general, consider leveraging more of the power of FORScan to aid in your diagnosis, not just for that odd O2 heater issue.
For example, the PCM in my 2004 Ranger (and probably your 2003 Mazda) reports "Fuel Injector Pulse Width" (bank 1 and 2) and a per-cylinder set of flags to report "Fuel Injector Primary Fault". Those values should be readily available in FORScan. They're probably in Torque Pro too, but you'd have to take the extra step of loading the "Ford PIDs". Checking those (and other PIDs) might help in your overall diagnosis.
Will add more if I think of something useful....
