Home/Honda/S2000/Honda S2000 AP1 (1999-2003)/Repair manual/Testing & Diagnostics/DTC P0118: ECT Sensor Circuit High Voltage
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DTC P0118: ECT Sensor Circuit High Voltage Honda S2000 AP1

Testing & Diagnostics 5 illustrations ~355 words

Note. Before you troubleshoot, record all freeze data and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Scheme 34

Scheme 34: DTC P0118: ECT Sensor Circuit High Voltage

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Scheme 38
  1. Turn the ignition switch ON (II).
  2. Check the ECT with a scan tool or the HDS. Is -4 °F (-20 °C) or less, or 5 V indicated? YES - Go to step 3. NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the ECT sensor and at the ECM.
  3. Turn the ignition switch OFF.
  4. Disconnect the ECT sensor 2P connector.
  5. Connect ECT sensor 2P connector terminals No. 1 and No. 2 with a jumper wire.
  6. Turn the ignition switch ON (II).
  7. Check the ECT with a scan tool or the HDS. Is -4 °F (-20 °C) or less, or 5 V indicated? YES - Go to step 8. NO - Replace the ECT sensor (see «SPECIAL TOOLS»(ref-221324-S23506078702006022400000) ).
  8. Turn the ignition switch OFF.
  9. Remove the jumper wire.
  10. Turn the ignition switch ON (II).
  11. Measure voltage between ECT sensor 2P connector terminal No. 2 and body ground. Is there about 5 V? YES - Go to step 13 . NO - Go to step 12.
  12. Measure voltage between ECM connector terminal C26 and body ground. Is there about 5 V? YES - Repair open in the wire between the ECM (C26) and the ECT sensor. NO - Substitute a known-good ECM (see «HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES»(ref-221328-S04997151962006022400000) ) and recheck. If normal ECT is indicated, replace the original ECM (see «ECM REPLACEMENT»(ref-221329-S30667517252006022400000) ).
  13. Turn the ignition switch OFF.
  14. Disconnect ECM connector C (31P).
  15. Connect ECT sensor 2P connector terminal No. 1 to body ground with a jumper wire.
  16. Check for continuity between ECM connector terminal C18 and body ground. Is there continuity? YES - Substitute a known-good ECM (see «HOW TO SUBSTITUTE THE ECM FOR TESTING PURPOSES»(ref-221328-S04997151962006022400000) ) and recheck. If normal ECT is indicated, replace the original ECM (see «ECM REPLACEMENT»(ref-221329-S30667517252006022400000) ). NO - Repair open in the wire between the ECM (C18) and the ECT sensor.