3-72 FUEL SYSTEM (DFI)
Inlet Air Pressure Sensor (Service Code 12)
If the reading is within the standard range, and check the
input voltage again at the sensor connector.
Remove the air cleaner housing (see Air Cleaner Housing
Disconnect the inlet air pressure sensor connector and
connect the harness adapter [A] between the sub harness
connector and inlet air pressure sensor connector.
Connect a digital meter to the harness adapter leads.
[B] Inlet Air Pressure Sensor
Special Tool - Sensor Harness Adapter: 57001–1561
Inlet Air Pressure Sensor Input Voltage
Connections to Sensor
Meter (+) → BL lead [C]
Meter (–) → BR/BK lead [D]
Measure the input voltage with the engine stopped.
Turn the ignition switch ON.
Input Voltage at Sensor Connector
4.75 ∼ 5.25 V DC
If the reading is out of the standard range, check the
wiring (see wiring diagram in this section).
If the reading is good, the input voltage is normal. Check
the output voltage.
Turn the ignition switch OFF.
Output Voltage Inspection
Measure the output voltage at the ECU in the same way
as input voltage inspection. Note the following.
Inlet Air Pressure Sensor Output Voltage
Connections to ECU
Meter (+) → Y/BL lead (terminal 17)
Meter (–) → BR/BK lead (terminal 14)
Output Voltage at ECU
The output voltage changes according to the local at-
The vacuum sensor output voltage is based on a nearly
perfect vacuum in the small chamber of the sensor. So,
the sensor indicates absolute vacuum pressure.
If the output voltage is within the usable range, check the
ECU for its ground, and power supply (see this chapter). If
the ground and power supply are good, replace the ECU.
3.80 ∼ 4.20 V DC at the standard
atmospheric pressure (101.32 kPa,
76 cmHg abs.)