FI SYSTEM DIAGNOSIS 12-47
Step 2
1) Connect the ECM coupler.
2) Disconnect the IAT sensor coupler.
3) Measure the IAT sensor resistance.
IAT sensor resistance: Approx. 2.58 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 ECT sensor. (12-62)
2
YES
• Dg or B/Br wire open or shorted to ground, or
poor O or N 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. 2.58 kΩ
50 °C (122 °F) Approx. 0.77 kΩ
80 °C (176 °F) Approx. 0.28 kΩ
110 °C (230 °F) Approx. 0.12 kΩ
ECM coupler (Harness side)
2
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