Possible cause of reoccurring p0136 code 2000 mustang 3.8

Question

Have replaced both downstream sensors and repaired wire harness replacing both connectors code clears for a while then returns. Have come to notice when I fill up on gas and drive on highway the light returns less than full tank the light stays off no other codes present no other symptoms other than light gas mileage seems normal per the 4 years I've owned the vehicle any ideas can't afford to fire the parts Canon at it lol

Answer 1

P0136 H02S sensor heater circuit malfunction

This code is Bank 1 Sensor 2,.Being Sensor 2 that job is to monitor the catalytic convertor, Bad and poor connection is what causes P0136, doing the wire repair is a good start, Another cause for a P0136 and Ford is famous for this is a exhaust leak right after the upstream 02 sensor.

Read more : https://www.autocodes.com/p0136_ford.html

Comments

No detection of an exhaust leak the code will clear it's self and return after I fill the gas tank and get on the highway and reach higher speeds under 3/4 tank the code clears itself and remains clear under all driving conditions seems to be related to full gas tank is what baffels me for ideas

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I just went through the wire diagram , I have tons of ford when it comes P0136. it mostly the sensor itself. Your going to need a volt meter or a scan tool that reads data. If you have ascan tool see if there is a data for the fuel system , that data should sat Fuel system closed, do this this , notice it when there is a full tank and close to empty tank. I see nothing how the instrument panel can cause this situation unless the code is really present and instrument panel is fooling

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Don't have either tool will have to check with shop that I use when needed see if their scan has that option it does read live data see what I can come up with on that thanks for the info