Metering Valve Sensor (MVS) Check
The metering valve sensor is a variable resistor that sends a metering valve position signal to the ECM. The sensor is connected to a 5 volt reference and has highest resistance at closed throttle. At wide open throttle (WOT), resistance is lowest, and output will be near 5 volts. A failure in the sensor will turn "ON" CEL at engine RPM less than approximately 1500. Light will turn 'OFF" above 1500 RPM if there is an MVS fault.
- This step checks for a good voltage reference at MVS connector. Normal range at terminal "A" is about 5 volts.
- This step checks for a good ground circuit through terminal "J" of ECM. Normal reading is about 5 volts.
- This step checks for an open or grounded circuit from the ECM to the MVS. If there is an open or ground, voltage will be low. Normal circuit reading is about 5 volts.
- This step checks for a faulty ECM or faulty wire to MVS connector terminal "B." Normal voltage at ECM with MVS harness disconnected is about 5 volts. Low voltage indicates a grounded wire or a faulty ECM connection or ECM.