Chart C-1D, Map Sensor Output

NOTE: Test numbers refer to test numbers on diagnostic chart.

This step checks MAP sensor output voltage to ECM. Without engine running, this voltage represents a barometric reading to ECM.
Applying a vacuum reading of 10 in. Hg to MAP sensor should cause voltage to be 1.2-2.3 volts less than voltage in step 1). When applying vacuum to sensor, change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
This step checks vacuum hoses to sensor for leaks and restrictions. Ensure no other vacuum devices are connected to MAP sensor hose.

MAP SENSOR VOLTAGE ⁽¹⁾

Altitude Meters

Altitude Feet

⁽²⁾ Voltage Range

Below 305

Below 1000

3.8-5.5V

305-610

1000-2000

3.6-5.3V

610-914

2000-3000

3.5-5.1V

914-1219

3000-4000

3.3-5.0V

1219-1524

4000-5000

3.2-4.8V

1524-1829

5000-6000

3.0-4.6V

1829-2133

6000-7000

2.9-4.5V

2133-2438

7000-8000

2.8-4.3V

2483-2743

8000-9000

2.6-4.2V

2743-3048

9000-10,000

2.5-4.0V

⁽¹⁾	Low Altitude = High Pressure = High Voltage

⁽²⁾	Voltage reading taken with key on/engine off

Fig 1: Chart C-1D Schematic, Checking MAP Sensor Output

Courtesy of ISUZU MOTOR CO.

Fig 2: Chart C-1D Flow Chart, Checking MAP Sensor Output

Courtesy of ISUZU MOTOR CO.