H40 - DTCs 1131, 1151, 1132, 1152: Upstream HO2S Not Switching

Diagnostic Trouble Codes (DTCs) 1131 and 1151 indicate the system is correcting RICH for an overly LEAN condition. HO2S voltage less than .45 volts.

DTCs 1132 and 1152 indicate the system is correcting LEAN for an overly RICH condition. HO2S voltage greater than .45 volts. DTCs 1130 and 1150 indicate the fuel control system has reached its maximum compensation for a lean or rich condition.

Possible Causes:

- Fuel System
- Excessive fuel pressure.
- Leaking fuel injector(s).
- Leaking pressure regulator.
- Low fuel pressure.
- Plugged injector(s).

- Induction System
- Air leaks after MAF.
- Vacuum leaks.
- Restricted air inlet.
- PCV system.

- Base Engine
- Oil over fill.
- Cam timing.
- Compression.

- Ignition
- Coil and secondary side of ignition system.

- Are there any obvious concerns?

YES -- REPAIR any of the problems found in the visual inspection. Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes

NO -- For DTCs 1130 and 1150: Go to H42. H42 - Check Fuel Pressure

All others: Go to H41. H41 - Initiate KOER Self-Test