Code 33 - Map Sensor Signal Volt Hi
The Manifold Absolute Pressure (MAP) sensor responds to changes in manifold pressure (vacuum). The ECM receives this information as a signal voltage that will vary from about 1-1.5 volts at idle to 4-4.5 volts at WOT. If the MAP sensor fails, the ECM will substitute a fixed MAP value and use the TPS to control fuel delivery. Code 33 will set when signal reading is too high for more than 8 seconds and the TPS voltage indicates throttle is closed. Engine misfire or a low and unstable idle may set Code 33. Disconnect MAP sensor and system will go to backup mode. If the misfire or idle condition remains, MAP sensor is good.
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- This test confirms Code 33 and presence of fault.
- If the ECM recognizes and sets Code 34, low MAP signal, the ECM and wiring are good.