MAP Sensor Check VINS T and V - Diesel Electronic Control (DEC) System

Fig. 024 - WIRING DIAGRAM for MAP Sensor Check. VIN T, VIN V:

MAP SENSOR CHECK

An Absolute Pressure Sensor (MAP) is used to monitor vacuum in the EGR vacuum circuit. It senses the amount of vacuum in the circuit and sends a signal back to the ECM. The signal is compared to the EGR duty cycle signal. If there is a difference in ECM command and MAP sensing, a CEL is set. The system can sense a high or low vacuum error, indicating a vacuum leak or faulty electrical component in the vacuum control system. Once a vacuum error is sensed, the CEL will go "ON" after 10 seconds and will not go "OFF" unless the key is shut "OFF".

Fig. 023 - Chart For MAP Sensor Check.:

1. Checks for V-ref. at MAP sensor harness. Normal voltage at Terminal "C" of MAP harness should be about 5 volts.
2. Checks for an open to ground in the MAP circuit to the ECM. Normal voltage is about 5 volts with a good ground.
3. Checks for proper circuit from the MAP signal wire to ECM Terminal "B". High voltage (about V-ref.) indicates an open ECM terminal or ECM. Low voltage is an open or grounded wire, or faulty MAP sensor.