Good day,

i have a 98 Civic hatchback with B18C1 swapped in it. I'm having a CEL #6 right now, and its killing me. Because of this ECT error, my car is difficult to start, idles like ****, drives like ****, VTEC is non existance.

1) i changed the sensor (the correct one, the one that send the signal to the ECU) but still doesnt fix the issue.
2) I used multimeter on the plug, it seems normal.
3) i measured resistance of the new sensor, reads normal
4) measured the grounding at Thermostat housing, reads 22V +/-

before this, i had TPS and IAT sensor fault too (input too high). But i managed to clear the faults.

Anyone can help me with the ECT error?

 

The wire colors on the ECT sensor plug are red/white and green/black. The red/white wire is the signal voltage wire. You must check continuity between the sensor plug and the ECU. If you have an OBD-1 ECU, you must check both the stock location and the adapter harness pin passing through to the ECU. If this is clean, check the green/black wire... from sensor plug to the junction plug under the intake manifold, and ultimately, back to the control ground pin at the ECU. Also, check to make sure your engine harness ground at the thermostat housing is clean and tight. If all of the above checks out, try another ECU.

 

Check all sensor plugs by wire color. The two wire and three wire plugs are not mechanically keyed, and can be plugged on to the wrong things.

The green-black wire should be 5 volts to ground (or negative post of the battery) with the key on. This voltage comes from the ECU and is teed in to several sensors (IAT, ECT, MAP, and TPS).

The wires on the thermostat housing should be zero volts to battery(-) with the key on. How did you measure 22 volts in a 12 volt system?

 

Okie... my bad guys... the ground is not reading 22v... checked the ground resistance, it was showing between .1 and .3, continuity between grounding points and batt negative post was good...so i assume the ground is good.

i went to check the voltage of the signal wire u mentioned... it reads 11.77V instead of the 5v it was suppose to read. what could had cause this ?

And now i have a new code... its the P1298 (ELD high input)

 

OMFG....!!! FOUND THE PROBLEM.... The plug was connected wrongly... mixed up the VTEC connector with the ECT switch

 

This is why I suggested checking for proper wire colors... mixing up the ECT and the VTP plugs is very common.