Honda Car Forum

My 2003 Honda Civic EX Coupe recently started misfiring on all cylinders, throwing codes P0300-P0304. I took it to the dealership and they told me I had a bad ELD and that when they diagnosed my car it threw a Honda specific code P1298. Honda wants to give me a new fuse box for $495 but if i get a new ELD and put it in myself is it likely to solve the misfiring problem, or are the two problems unrelated? I understand that the ELD changes the alternator voltage based on the electrical load on the car. Can it be telling the alternator to run too low and not create enough voltage to make nice sparks, or do I have deeper problems?

the two problems are unrelated.first, on the ELD, it appears to be a product problem..Honda has a dealer service bulletin 05-006 on the condition:SYMPTOMDTC P1298 (electrical load detector (ELD) circuit highvoltage) is stored in the ECM/PCM.PROBABLE CAUSEThe electronic load detector (ELD) has a faulty solderjoint.CORRECTIVE ACTIONReplace the ELD.NOTE: Previously, if an ELD required replacement, youhad to replace the under-hood fuse/relay box. Toreduce repair costs, replacement ELDs are nowavailable.PARTS INFORMATIONElectronic Load Detector:P/N 38255-S5A-003, H/C 7987571I would suggest you contact your Honda distributor to request that they pay for the repair of this product problem. Its worth a shot. If the car is in the U.S. the distributor is American Honda and their phone number is 1-800-999-1009. They are usually pretty good about goodwill for product problems.as for the misfires, the ELD problem is too high a voltage, not too low. for multiple cylinder misfires you need to look to causes that affect all cylinders. typically that is limited to either a bad ignition coil (most frequent cause), a cracked distributor cap (unusual on a 2003), a gas tank full of contaminated fuel (water, high alcohol content or dirt; again less likely) or an air leak between the throtte body and the intake valves (intake gasket, big vacuum hose off). Its almost always a bad coil.hope that helps