When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
You may be looking at a broken wire or burnt wire... Look where the wires route along the frame and see if anything is near the muffler or rubbing a bracket.......
P0138 FORD - O2 Sensor Circuit High Voltage Bank 1 Sensor
P0138 FORD Possible Causes
Faulty Rear Heated Oxygen Sensor Bank 1 Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Intake air leaks Exhaust gas leaks Inappropriate fuel pressure
Faulty fuel injectors
You may be looking at a broken wire or burnt wire... Look where the wires route along the frame and see if anything is near the muffler or rubbing a bracket.......
P0138 FORD - O2 Sensor Circuit High Voltage Bank 1 Sensor
P0138 FORD Possible Causes
Faulty Rear Heated Oxygen Sensor Bank 1 Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Intake air leaks Exhaust gas leaks Inappropriate fuel pressure
Faulty fuel injectors
I replaced o2 sensor and both catalytic converters code still comes up.... I reset all codes and light stays off and then comes on after 50 miles
That was some expensive guess work.
Originally Posted by steve(ill)
You may be looking at a broken wire or burnt wire... Look where the wires route along the frame and see if anything is near the muffler or rubbing a bracket.......
P0138 FORD - O2 Sensor Circuit High Voltage Bank 1 Sensor
P0138 FORD Possible Causes
Faulty Rear Heated Oxygen Sensor Bank 1 Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
Intake air leaks Exhaust gas leaks Inappropriate fuel pressure
Faulty fuel injectors
I'd HIGHLY recommend using Ford's documentation instead of generic things posted on the internet when dealing with Ford's fault codes. The above is rather "not very useful" in this case as it tries to apply to a wide variety of manufacturers.
The P0138 DTC indicates that the voltage sensed by the PCM for B1S2 exceeds 1.5 volts, usually due to a short between the signal line and vehicle power. The short could be in the sensor itself, the wiring harness, or the PCM. The PCED has the diagnostic procedure that should be followed.