P0133,P0135,P1131,P1132 Mazda PU

Messages
328
Location
Pennsylvania
Get these codes using Autel AutoLink AK319 on my Mazda B4000 pickup. Also with the I/M function getting CAT = "INC", not the "OK" reading given on most fields. I'm guessing INC is inconclusive but I haven't researched it yet. Seems odd to me that P1131 states "HO2S Bank 1 Sensor 1, Signal below .45 v (A/F ratio too lean)" while P1132 is "HO2S Bank 1 Sensor 1, Signal above .45 v (A/F ratio too rich)" Any suggestions on how to proceed, tests that may isolate problem? The engine leaks some oil, thinking this is a problem with the CAT and both O2 sensors as a guess.
 
Messages
2,872
Location
USA
Those codes are all related to sensor 1. Check sensor heater ohms and replace sensor if bad.
 
Messages
1,556
Location
TX, USA
Bank 1 Sensor 1. For 6 or 8 cylinders: You have to locate where the Cylinder #1 is, then that side is Bank 1. Sensor 1 is before the catalytic converter which is usually the one on top. Try replacing it. Go to RockAuto to find the part numbers.
 
Messages
11,454
Location
Illinois
As others have noted, it's a before the cat converter sensor. Disconnect one and see if you get codes for both or just one. If you get codes for the same sensor, you found it. If you get additional codes for another sensor, you are on bank 2 (or on one of the post cat converters, but it should tell you if you got the right bank.) Or you could just google it, as I'm sure someone out there has located bank 1 sensor 1. As others have suggested, once located, check wiring, connectors, test out the sensor with an ohm meter, etc.
 

schuylkill

Thread starter
Messages
328
Location
Pennsylvania
Thanks all. I haven't checked it out yet, truck mostly sits. It runs fine from start up in warmer weather, if its cold needs to heat up. I'll post any updates. smile
 
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