This 2001 Honda Civic came in with a multitude of problems one of which was a code P1298 stored for an ELD fault (electric load detector circuit input high). I had never had to actually test one of these before although I knew that they existed. The ELD sends a signal to the engine control computer so that the computer can adjust the alternator output in relation to power consumption. The ELD is located in the underhood fuse box. I am pointing to it with my screw driver.
To test the ELD I had to lift the underhood fuse box and remove the bottom cover. Once removed I could access the wiring for the ELD. The wire on the far right of the connector is power supply (battery voltage).
The wire in the middle of the connector is battery ground.
The wire on the far left of the connector is a five volt signal sent from the computer. The ELD will pull the voltage lower with increased system load and should vary with a change in load. For example if the blower or headlights are turned on it should drop. This particular unit was stuck at 3.81 volts and would not change with no loads or full loads applied. If the voltage had been near zero I would have had to unplug the connector and see if the five volt reference signal was being sent by the computer and wiring.
After testing and finding a faulty ELD, it was very easy to change. I removed the four adjoining phillips headed screws that held the two PAL fuses in place.
I released the latch on the harness connector and unplugged the connector.
With the wiring removed I simply lifted the unit. Slid the bar out and installed the new unit.
Below are a couple of pictures of the actual ELD part from Honda.
On a 96 Civic LX: Speedometer pulsates when it acutally works. Lights pulsate when speedometer does. Came up with codes for IAT sensor, VSS, ELD, Primary and Secondary O2 sensor heater. Checked fuses, wiring harness behind the motor, and changed VSS. Nothing has changed. Checked voltage on ELD and far left pulsates between 3.5V and 4.8V depending on load. Middle barely reads regardless. Far right only reads .45V to .56V, not the 12V your pictured showed. Is this a bad ELD? BTW, great pics, very informative.
speedometer jumps around when it actually works; checked fuses, changed speed sensor, checked c115 wire harness for shorts and nothing worked. when speedometer jumps the dash lights flicker. came up with several codes: IAT sensor, VSS, ELD, primary O2 sensor heater, and secondary O2 sensor heater. Checked ELD voltage according to your pictures. Far left fluctuates between 3.5 and 4.8 depending on the load. Far right only reads .45V to .75V depending on the load, not the 12V that you show. Middle wire barely reads most of the time. Would this all be caused by a bad ELD?
Yes, it would be part of the harness assembly but you should be able to obtain a used one a a salvage yard. If it is not broken too badly you may be able to still use it. Make sure the wires are properly separated and that they do not feel like they will fall out.
Sparky
When I replaced the ELD on my 2002 honda civic I accidentally pressed too hard and broke the 3 pin connector that attaches to the back of the ELD. Is this a separate part that can be replaced – Honda says the whole harness has to be replaced. Please advise.
Thanks
I do not know if that one is available separately or not. I would suggest contacting another dealer just in case the counter person was not performing a well as he/she could have been. I do this a s a fairly common course of business. Sometimes people just have bad days and do not see everything that is listed. Sometimes the parts are not available too. Second set of eyes looking are kind of a like a doctors second opinion.