my 2001 jeep grand cerokee was coding p0138. this was an oxygen sensor. I replace the oxygen sensor and now it is coding for all four oxygen sensors I cleared the codes and it is back on again.
Changing one O2 sensor will not cause any others to go out. O2 sensors get slower to react with age and miles. It is probably a good idea to change both upstream sensors if the vehicle has over 100,000 miles on it. This may result in slightly better fuel mileage.
Search Jeep Grand Cherokee Questions
Jeep Grand Cherokee Experts