4-54 FI SYSTEM DIAGNOSIS
Step 2
1) Turn the ignition switch to OFF.
2) Measure the IAT sensor resistance.
IAT sensor resistance: Approx. 2.45 k
Ω
at 20 °C
(Terminal – Terminal)
09900-25008: Multi-circuit tester set
Tester knob indication: Resistance (
Ω
)
Is the resistance OK?
IAT sensor specification
NOTE:
IAT sensor resistance measurement method is the same way as
that of the ECT sensor. Refer to page 7-7 for details.
2
YES
• Dg or B/Br wire open or shorted to ground, or
poor
Q
or
S
connection
• If wire and connection are OK, intermittent trou-
ble or faulty ECM.
• Recheck each terminal and wire harness for
open circuit and poor connection.
• Replace the ECM with a known good one, and
inspect it again.
NO
Replace the IAT sensor with a new one.
Intake Air Temp
Resistance
20 °C
Approx. 2.45 k
Ω
50 °C
Approx. 0.808 k
Ω
80 °C
Approx. 0.322 k
Ω
110 °C
Approx. 0.148 k
Ω
ECM couplers (Harness side)
2