FI SYSTEM DIAGNOSIS 4-55 Step 2 2 1) Turn the ignition switch OFF. 2) Measure the IAT sensor resistance. IAT sensor resistance: Approx. 2.45 kΩ at 20 °C (68 °F) (Terminal – Terminal) 09900-25008: Multi-circuit tester set Tester knob indication: Resistance (Ω) Is the resistance OK? 2 • Dg or B/Br wire open or shorted to ground, or ECM coupler (Harness side) poor Q or S connection (Black) (Gray) • If wire and connection are OK, intermittent trou- YES 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. E IAT sensor specification L Intake Air Temp Resistance P 20 °C (68 °F) Approx. 2.45 kΩ 50 °C (122 °F) Approx. 0.808 kΩ M 80 °C (176 °F) Approx. 0.322 kΩ 110 °C (230 °F) Approx. 0.148 kΩ A NOTE: S IAT sensor resistance measurement method is the same way as that of the ECT sensor. Refer to page 7-7 for details.