3-50 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
Removal in this chapter).
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.
Inlet Air Pressure Sensor [B]
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
Standard: DC 4.75 ∼ 5.25 V
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.
Inlet Air Pressure Sensor Output Voltage
Connections to ECU
Meter (+) → Y/BL lead (terminal 8)
Meter (–) → BR/BK lead (terminal 28)
Output Voltage at ECU
Usable Range: DC 3.80 ∼ 4.20 V at the standard
atmospheric pressure (101.32 kPa, 76
The output voltage changes according to the local at-
The inlet air pressure sensor output voltage is based
on a nearly perfect vacuum in the small chamber of the
sensor. So, the sensor indicates absolute vacuum pres-
If the output voltage is within the usable range, check
the ECU for its ground, and power supply (see ECU
Power Supply Inspection in this chapter). If the ground
and power supply are good, replace the ECU (see ECU
Removal/Installation in this chapter).