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2007 Honda Civic P0118 Code: Diagnosis and Solutions for ECT Sensor or Wiring Issues

Model: 2007 Honda Civic Fault Code: P0118 Posted: 2019-04-02 18:46

I recently received a P0118 diagnostic code on my 2007 Honda Civic. I've already replaced the ECT (Engine Coolant Temperature) sensor, the thermostat, and multiple coolant sensors — including one at the radiator base and another in the coolant housing. Despite these replacements, the P0118 code has returned. Given that the code indicates an open circuit in the sensor or wiring, I suspect either a faulty connection or an issue with the PCM (Powertrain Control Module). However, I don't have access to a voltmeter and am not experienced with electrical diagnostics. I'm seeking advice on how to troubleshoot this issue effectively without specialized tools. Any guidance would be greatly appreciated.

Related fault codes
P0118
Comments (3)
Anonymous 2019-04-03 11:48

Without a multimeter, your best option is to perform a wiggle test on the ECT #1 connector wiring. The P0118 code typically points to an open circuit in either the sensor or its wiring. Check if the engine runs normally — does it start and run smoothly?

Anonymous 2019-04-03 11:52

Cj1, the car starts fine, but occasionally runs roughly for a few seconds before returning to normal. I've also noticed a significant drop in fuel efficiency and reduced overall power compared to before. While I can get access to a voltmeter, my experience with wiring diagnostics is limited.

Anonymous 2019-04-03 13:48

Regarding ECT#1 connector pins when disconnected from sensor. Should be 5v on one pin and ground 0 ohms on the other.