From Ford manual:
H40 DTCs P1131, P1132, P1151 AND P1152: UPSTREAM HO2S NOT SWITCHING. DTC P1130: FUEL SYSTEM NOT SWITCHING AT FUEL TRIM (RICH OR LEAN)
Diagnostic Trouble Codes (DTCs) P1131 bank 1 (Cylinder 1) and P1151 bank 2 indicate the fuel/air ratio is correcting rich for an overly lean condition. The HO2S voltage is less than 0.45 volt. DTCs P1132 bank 1 (Cylinder 1) and P1152 bank 2 indicate the fuel/air ratio is correcting lean for an overly rich condition. The HO2S voltage is greater than 0.45 volt.
DTC P1130 and P1150 indicate the fuel control system has reached maximum compensation for a lean or rich condition and the HO2S is not switching.
DTC/HO2S Reference List
-- HO2S-11 = DTCs P1131, P1132 and P1130
-- HO2S-21 = DTCs P1151, P1152 and P1150
Possible causes:
Fuel system
-- Excessive fuel pressure.
-- Leaking fuel injector(s).
-- Leaking fuel pressure regulator.
-- Low fuel pressure or running out of fuel.
-- Contaminated fuel injector(s)
-- Vapor recovery system
Induction system
-- Air leaks after the MAF.
-- Vacuum leaks (vacuum lines and gaskets).
-- Restricted air inlet.
-- PCV system.
-- Improperly seated engine oil dipstick.
EGR System
-- Leaking gasket.
-- Stuck open EGR valve.
-- Leaking diaphragm.
Base engine
-- Oil overfill.
-- Cam timing.
-- Cylinder compression.
-- Exhaust leaks before or near the HO2Ss.
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.
Are any of the above concerns present?
Yes
REPAIR as necessary. COMPLETE PCM Reset to clear DTCs.
