98 Ranger with 4.0 engine. Has been awhile but the engine code 1151 has come up again. This would be the third time this O2 sensor supposedly has gone bad. Any one have any experience with this recurring type of problem?? Also looking for a way to measure the output voltage from the senor to make sure its really bad. Anyone able to help with this please o rpoint me to where it can be found ??

Thanks for your help !!!

Smitty

 

Looking at my Ranger manual here, they don't have a code 1151. Any code that has to do with the powertrain has a PO in front of it. The codes for for O2 sensors problems are PO131 to PO161. The book says "low voltages generated by the sensor depend upon good clean connections which should be checked whenever a malfunction of sensor is suspected"(Hanes Manual: Ford Ranger: Emission Control Systems pg. 6-8).
Which basically means to warm up the engine to to normal operating temp, disconnect the O2 sensor harness, on sensor side with volt meter check for constant current from 0.35 to 0.55 millivolt. On the Harness side just turn the key to the on position and check the voltage. Should be 12 to 13 volts
If current outside those ranges the O2 sensor is bad if not check some of the other sensors.