If you have more than 100K miles on the O2 sensor, yes, try replacing it.
From TSB,
Diagnostic Trouble Code Description Possible Causes
P1151 - Lack of HO2S-21 Switch (Bank 2-Radiator side Upper Sensor
Fuel Trim at Limit. The HEGO Sensor is monitored for switching. The code will set when the HO2S fails to switch due to circuit or fuel at or exceeding a calibrated limit.
Electrical:
�· Short to VPWR or VREF in harness or HO2S
�· HO2S circuit shorted to Ground
�· Water in harness connector
�· Open circuit
�· Corrosion or poor mating terminals and wiring
�· Damaged HO2S
�· Damaged PCM (other DTCs should be present)
Fuel System:
�· Excessive fuel pressure (stuck fuel pressure regulator, restricted fuel return lines, etc.)
�· Leaking/contaminated fuel injectors or fuel pressure regulator
�· Low fuel pressure or running out of fuel (fuel pump concern, fuel supply line restrictions, low fuel level, etc.)
�· Vapor recovery system (stuck VMV, etc.)
Induction System:
�· MAF contamination
�· Air leaks between MAF and throttle plate
�· PCV system / Other vacuum leaks
�· Improperly seated engine oil dipstick
EGR System:
�· Leaking gasket
�· Stuck EGR valve / Leaking diaphragm or EVR
Base Engine:
�· Oil overfill
�· Incorrect cylinder compression
�· Exhaust leaks before or near the HO2S
�· Secondary air stuck on
Last edited by Tony2005; 05/08/06 02:51 PM.
