4-48 FI SYSTEM DIAGNOSIS
Step 2
1) Turn the ignition switch OFF.
2) Disconnect the IAT sensor coupler.
3) Measure the IAT sensor resistance.
IAT sensor resistance: Approx. 2.45 k
Ω
at 20 °C (68 °F)
(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 ET sensor. Refer to page 4-70 for details.
2
YES
• Y/R or B/Br wire open or shorted to ground, or
poor 5 or T 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 (68 °F) Approx. 2.45 kΩ
80 °C (140 °F) Approx. 0.32 kΩ
ECM coupler (Harness side)
2
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