johnheibel

I have a '96 E320 and I just solved a problem with it I thought I'd share. After putting a bottle of cheap fuel injector cleaner in my gas tank, the first time I started and drove it, the "Check Engine" and "Engine Electronics" warning lights came on. The engine sounded and drove fine and I drove it for several days while researching and fearing what "electronic" problem it could be. Went to AutoZone, and for free they hooked up their code reader and found only one error code listed "PO441". That code is "Evaporative Emission Control System Incorrect Purge Flow." I had previously suspected it had been something to do with the gas cap and had cleaned it, flipped over it's gasket and inspected and cleaned the tank nossle area. But everytime I started the car the warning lights would come on. Apparently, even if the problem is fixed, the warning lights do not reset on their own. It tries to force you to go to a repair shop to have it checked, fixed (riped off) and reset the system. First, I think the whole problem was caused by some fuel injector cleaner getting in the evaporation tube line near the cap nossle and temporarly screwing up the recirculation system.

The way I reset the codes and stopped the warning lights from going on everytime I started it, was to disconnect the negative side of the battery under the rear seat, for a few minutes, then reconnecting it. Now everything works fine.

shawnmichael

I think I've heard of that working for most cars to clear most codes (unless they still exist). My question is, is there a good way to do this in general and do I risk problems disconnecting the battery? I ask because I disconnected my positive terminal on an F150 years go an it wiped the ECU. The truck, which was fairly new with probably 20k miles wouldn't idle anymore and when I took it in (playing dumb) they said that the ECU was wiped. They asked if I had disconnected the battery to which I replied "Huh? No. Why would I do that?" So am I always safe to disconnect the negative terminal without risk of computer problems?

johnheibel

I don't know about your newer F150, but my older F250, Jeep and other vehicles including this '96 E320, I have changed out the batteries for new ones without causing any ECU computer problems. Their memories or programming seem uneffected. The only problem is that I usually loose my radio station button programming assignments.