DTC 33

The Manifold Absolute Pressure Sensor (MAP) responds to changes in manifold pressure and vacuum. The ECM receives this information as a signal voltage that will vary from about 1 to 1.5 volts at idle to 4 to 4.5 volts at wide open throttle (WOT).

If the MAP sensor fails, the ECM will substitute a fixed MAP value and use the Throttle Position Sensor (TPS) to control fuel delivery.

Code 33 will set when:

^ Signal is too high for a time greater than 5 seconds.
^ TPS voltage indicates throttle is closed.

Engine misfire or a low unstable idle may set Code 33. Disconnect MAP sensor and system will go into backup mode.

1. Confirms Code 33 and that fault is present.
2. If the ECM recognizes and sets Code 34, 10v MAP signal voltage, the ECM and wiring are OK.