Before servicing DTCs P0171, P0172, P0174 and P0175, verify with the customer that before the "Check Engine Light" came on, the vehicle did not run out of fuel.
Diagnostic Trouble Codes (DTCs) P1131 and P1151 indicate the system is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt.
DTCs P1132 and P1152 indicate the system is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.
DTCs P1130 and P1150 indicate the fuel control system has reached its maximum compensation for a lean or rich condition and HO2S is not switching.
DTC P0171, left bank, and DTC P0174, right bank, indicate the fuel/air ratio is too lean. The system is at the rich limit.
DTC P0172, left bank, and DTC P0175, right bank, indicate the fuel/air ratio is too rich. The system is at the lean limit.
DTC/HO2S Reference List
-- HO2S-11 = DTCs P1130, P1131, P1132, P0171 and P0172
-- HO2S-21 = DTCs P1150, P1151, P1152, P0174 and P0175
-- Excessive fuel pressure.
-- Leaking fuel injector(s).
-- Leaking fuel pressure regulator.
-- Low fuel pressure.
-- Plugged injector(s).
-- Damaged/disconnected HO2S circuit.
-- Air leaks after MAF.
-- Vacuum leaks.
-- Restricted air inlet.
-- PCV system.
-- Oil overfill.
-- Cam timing.
-- Coil and secondary side of ignition system.
l Check air intake for leaks, obstructions, and damage.
l Check air filter, air filter housing for blockage.
l Check positive crankcase ventilation system integrity.
l Check engine vacuum integrity.
l Are there any obvious concerns?
REPAIR any of the problems found in the visual inspection. RERUN «Quick Test».
GO to «H41».