12-38 FI SYSTEM DIAGNOSIS
Step 2
1) If necessary, connect the ECM coupler.
2) Disconnect the ECT sensor coupler.
3) Measure the ECT sensor resistance.
ECT 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?
ECT sensor specification
YES
• B/Bl or B/Br wire open or shorted to ground, or
poor
L
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 ECT sensor with a new one.
Engine Coolant Temp.
Resistance
20 °C (68 °F)
Approx. 2.58 k
Ω
50 °C (122 °F)
Approx. 0.77 k
Ω
80 °C (176 °F)
Approx. 0.28 k
Ω
110 °C (230 °F)
Approx. 0.12 k
Ω
2
ECM coupler (Harness side)
2