Hello, I'm new to the Honda cars and I recently picked up a 1996 Honda Accord 4 door LX 4-cyl. The car has 230k miles and runs good! Everything still works and I'm pleasently surprised at how it drives with this many miles. If the odometer didn't say so I would swear this car has half those miles. It would appear that the first tank of gas I've run through it is going to net in the low 20's for gas mileage. I expected it to be higher with this car and a 4-cyl. This is mixed city and highway miles.

Anyways, a couple of questions. The check engine light is on so i went to Autozone and had them read the codes:

1. P0135 sensor 1 heater system malfunction
2. P0141 Secondary circuit heater malfunction
3. P0401 EGR insufficient flow

The guy at Autozone said it appeared that this could all be the primary O2 sensor not working correctly which could cause the other two to kick on. I would like to hear what you think about that. I read on another thread that if I trace back the wire and measure the resistance (should be 10ohms) that would give me a clue. If it is an open circuit that would definetely be bad.

Also, with this many miles, the oil appears the have not been changed recently so I'm going to change that and the filter. Any thoughts on what to use? When I was at Autozone I saw a package deal with Pennzoil 'High Mileage' oil and filter for $20. What about the ATF? I don't have any manuals or books so is there a place to find directions on changing that out?

Any ideas would be very appreciated.

Thanks!

Mike

 

Suggest resetting ECU (pull BackUp fuse in underhood fuse box for 15-20 secs) and see what codes return.

Note, if you have a Honda radio you will need the security code to reenable the radio. Lot's of threads on how to get this code, but check underside of ash tray and inside glove box. Many folks write them down somewhere on the car.

If same codes return, fix the two O2 sensor codes first. Replacement of O2 sensor is likely fix, but check resistance of sensor heater to confirm. You will need an O2 socket to remove/replace the sensors, although a large open end wrench will work for some sensor locations. Warm engine for 5-10 minutes to ease removal effort. Careful for hot exhaust parts.

Oil and filter type is not as important as frequent changes. Pennzoil is fine.

Suggest draining/replacing auto trans fluid w/ honda ATF Z1. If it's especially dirty or has a burnt smell, you may want to consider a full displacement. See "atomatic fluid" in youtube search for decription of process.

good luck

 

Welcome to the HAF...
If your car has that many miles on it...you need to find out if and or what was ever done to your car and when.
If you can't...Do change the O2 sensors anyway unless they are new..they are due for a change.
That oil change special is worth the money and the filter is a good one.

WheelBrokerAng

 

Check the DIY section for a manual you can download. Might also pick up a Haynes or Chilton (both).

If the P0401s come back might want to clean the egr ports and valve. There is a good write up in the DIY section as well.

 

For the gas mileage, you might to do some routine maintenance if it hasn't been done recently, like spark plugs, distributor rotor and cap, air filter, oil change, PCV valve, check tire pressure, etc.

 

P0135 would reduce fuel efficiency slightly as the "cold sensor" would require longer to reach closed loop operation. Unsure how much difference this would make.

W/ my 94EX, I get about 27 avg per tank on commute of 38 miles round trip w/ about a 70/30 mix of highway/suburban driving. It will do better than 30 mpg on strictly highway miles.

good luck

 

Thanks everyone....good info.

I will try resetting the ecm and see what happens and go from there.