Map Sensor Check
The MAP sensor monitors vacuum in EGR circuit. If there is a difference in the ECM command and what is at the EGR valve (sensed by MAP sensor), the ECM makes minor adjustments to correct the vacuum level. When a major difference is sensed, the ECM recognizes a fault and sends a full EGR signal.
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- This step checks for 5-volt reference signal to MAP sensor. About 5 volts should be present at terminal "C" with ignition on.
- This checks for complete circuit from MAP sensor back through sensor ground wire. About 5 volts should be present at terminal "C" with ignition on.
- This checks for normal response from MAP sensor to an external vacuum signal. There should be an immediate voltage indication as vacuum is applied.