Diesel Data: Automotive Repair

DTC 34

Code 34 - MAP Sensor:




Wiring Diagram For Code 34 - MAP Sensor (Voltage Low):







CODE 34 - MAP SENSOR (SIGNAL VOLTAGE LOW)

Circuit Description:

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 to 1.5 volts at idle to 4-4.5 volts at wide open throttle.

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 34 will set when signal is too low and ignition is turned on.




Test Description:

1. Confirms Code 34 and that fault is still present.



2. If the ECM recognizes and sets Code 33, high MAP signal, the ECM and wiring are OK.