Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
DTC P1133 is most likely caused by one of the following conditions:
- High fuel pressure - the system will go rich if fuel pressure is too high. The PCM can compensate for some increase. However, if the fuel pressure becomes too high, DTC P0172 will be set. Diagnose fuel system.
- A leaking or malfunctioning injector can cause the system to go rich.
- The MAP sensor - an output that causes the PCM to sense a higher than normal manifold pressure, indicative of a low vacuum, can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the sensor is disconnected.
- Inspect for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the regulator.
- An intermittent TP sensor output will cause the system to go rich due to a false indication of the engine accelerating.
- Inspect HO2S 1 for silicone contamination from fuel or use of improper RTV sealant. The sensor may have a White powdery coating, which may result in a high but false voltage signal, indicating a rich exhaust condition. The PCM will then reduce the amount of fuel that is delivered to the engine, causing a severe surge or driveability problem.