Manifold Absolute Pressure (Map) Sensor

Sensor is mounted to right center of firewall. To test MAP sensor on vehicle, turn ignition on. Connect voltmeter between ground and indicated ECM connector terminal (backprobe ECM terminal). See the MAP SENSOR OUTPUT VOLTAGE (ON-VEHICLE) table.
If voltage not within specs., see CODE 31 or CODE 32 in the TESTS W/CODES article. To bench test pressure sensor, see the MAP SENSOR OUTPUT VOLTAGE (OFF-VEHICLE) table. If voltage is not within specification, replace MAP sensor.

MAP SENSOR OUTPUT VOLTAGE (ON-VEHICLE)

Altitude (Feet)

Vacuum (In. Hg)

⁽¹⁾⁽²⁾ Output Voltage

3.5-3.8

1000

3.4-3.7

2000

3.3-3.6

3000

3.2-3.5

4000

3.1-3.4

5000

3.0-3.3

6000

2.9-3.2

7000

2.8-3.1

8000

2.7-3.0

9000

2.6-3.9

10,000

2.5-2.8

⁽¹⁾	MAP sensor output voltage tested with coupler connected to ECM. Before testing MAP sensor output voltage, ensure ECM supply voltage is 4.75-5.25 volts at connector terminal B1 (Light Green wire) and terminal A3 (Light Green/Red wire).

⁽²⁾	Output voltage is checked at ECM connector terminal B3 (Light Green/Red wire) and terminal B9 (Light Green/Black wire). Start engine, if possible, and see if output voltage varies.

MAP SENSOR OUTPUT VOLTAGE (OFF-VEHICLE)

Altitude (Feet)

Vacuum (In. Hg)

⁽¹⁾⁽²⁾ Output Voltage

0-2000

28-30

3.1-3.6

2001-5000

25-28

2.8-3.4

5001-8000

22-25

2.6-3.1

8001-10,000

20-22

2.4-3.9

⁽¹⁾	MAP sensor output voltage is tested with three 1.5-volt batteries connected in series (output 4.5-5.0 volts). Positive lead of batteries is connected to VIN terminal. Negative lead of batteries is connected to ground terminal. Check output voltage between VOUT terminal and ground.

⁽²⁾	Voltage should reduce when up to 15 in. Hg of vacuum is applied to MAP sensor.