Code 34 - Map Sensor Signal Volt Lo (A/F/J/N/P Body)

The Manifold Absolute Pressure sensor (MAP) 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 wide open throttle. If MAP sensor fails the ECM will substitute a fixed MAP value and use the TPS to control fuel delivery. Code 34 will set when signal reading is too low and ignition is turned on.

1. This test confirms Code 34, and that fault is present.
2. If the ECM recognizes and sets Code 33, high MAP signal, the ECM and wiring are okay.

Fig 1: Code 34 Flow Chart: MAP Sensor Signal Voltage Low

Fig 2: Code 34 Flow Chart: MAP Sensor Signal Voltage Low

Fig 3: Code 34 Schematic: MAP Sensor Signal Voltage Low