FWIW (for what its worth) LOL!
For the better part of a year, my son's 03MaxSE was illuminating the 'check wallet' light! All codes pointed to O2 sensor problems. After changing out (multiple times) sensors,(costing him a bundle), clearing the codes, work for a week/month, finally sent his car to the dealer. Their 'master mechanic' came back with a diagnostic that the engine harness must have a partial broken wire, couldn't (or wouldn't) search it out & repair (too much $$$) and suggested to change the harness out.... at $2800. LOL! I found a used harness ($400.) and replaced it myself over Xmas (pita)! The codes showed back up 2 days later on his way back to school..... thank God he didn't pay the dealer! I did more research.... and found out that the 2001 Max s' had grounding problems with their harnesses. (I realise that his 03Max is a different engine/harness, but What's to lose!) As my son was away at school, I suggested he buy some 10Gauge ground wire with connectors, attach 1 lead from battery GRD to engine, and another from Batt Grd to frame (clean surfaces, please)! Viola, Not only did the codes clear by themselves within 2 days (code reader was with me) but there have been 0 codes since!
So, to all that may have O2 problems, try that for the $15.
best,
Sandy

 

good call sorry for your troubles.. run a search on "the big three" or "big three cables" or big three ground" ..something like that.. and u sould come across where people have done close to the same thing.. glad to hear shes running good..