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 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.