My Mom’s 2000 Civic LX with about 72,000 miles threw a CEL recently. I did the jumper and counted the short and long CEL blinks and determined a code 41 was the cause. Took it to the local Honda dealership and they determined that it was the ECU and not the O2 sensor. They wanted $1500
to replace it. They also identified several other items they recommended replacing, all of which was BS, bringing the total repair bill to $3200. This is more than the car is probably worth and she only puts about 2000 miles a year on this car.

Anyways, I know it’s easy to replace the ECU and I know that I need to get a used ECU with the exact same part number (37820-P2E-A92.). This Honda does not have an immobilizer so I don’t have to worry about that. What I’m not able to determine is whether or not any reprogramming is necessary.

Any help and advice would be greatly appreciated!

 

2000 civic, get an obd2 reader or take it to some part store that offers to read the code and give you a print out. Come back with the codes. If it comes back as o2 heater circuit failure you can pick up another o2 sensor while your there. No universal ****, straight plug in.

 

Tony, I didn’t think this car had an OBD2 connector, but it does! I connected my scanner up, but I couldn’t get it to work. Probably user error and I’ll try again tomorrow and post up the results.

Thanks

 

Any USDM car 1996 or newer has an OBDII connector. Try your scanner on another car to become familiar with its operation. If the scanner didn't power up at all this is often a blown fuse in the car. If the scanner does power up but can't communicate, that is usually a bad ECU.

If the ECU is to be replaced the new one does not need to be reprogrammed. Always disconnect the battery before unplugging or plugging in an ECU.

 

If it’s automatic, I’ve got the one from my 2000 Civic LX. If you need it, let me know.

 

Resolved the user error, which was not hitting “connect” at the bottom of the OBDFusion interface.

There is only one code - P0135.

 

I figured out what the user error was in using my OBDII scanner and was able to scan the vehicle. The only code the was found was P0135. I followed a "How to troubleshoot Code P1035 (1995-2000 Honda 1.6L0" article and using a multimeter found the following for the sensor located on the front of the engine:

1. Verified that heater element is getting power - ~12.12 volts
2. Verified that the heater element is getting ground - ~12.12 volts
3. Test the heater element's resistance and got a reading of 5.1

These test results seem to indicate that the O2 sensor is working, but I don't have enough experience to be 100% confident that this is indeed a fact. If the O2 sensor is indeed ok, does that indicate that the ECU is faulty?

A little back story on this may be useful. This car rarely gets driven as its mostly used to take my Mom to doctor appointments or shopping. She's the original owner and it only has about 72,0000 miles and the local Honda dealership has performed all maintenance and work on the vehicle. A few weeks ago, I took her for a ride to go view the wildflower super bloom occurring in the mountains around Bakersfield, CA. The drive was about 30 miles each way on the freeway and it was a warm day so we had that AC on, but it wasn't working very well. The car ran fine, except the AC issue, Two days later when I started the car, the Check Engine Light came on. I drove it anyways as Mom had a doctor appointment and the car was having noticeable idling issues, though it never stalled. After the doctor appointment, the idling issue "fixed" itself. The idling issue and CEL are intermittent issues.

Appreciate and advice or insight on how to proceed and thanks to those who have responded so far.

David

 

Thanks mk378! That was what I was hoping to hear should I have to replace the ECU>

David

 

I’m interested. Is your ECU part no 37820-P2E-A92?

David

 

let me look

I looked.

 

That’s the right one. Any issues b4 it was removed? How much?

Thx,

David

 

No issues. The car was bought with a rod knocking as a project car, and I pulled everything out for the swap.

$40

 

I replaced the ECU with a used one and the CEL/P0135 persisted. Replaced the O2 sensor on the exhaust manifold with a new Denso unit and the CEL is gone. Completed the idle learn process and the car is idling fine.

I’m appalled by the dishonesty of Barber Honda in Bakersfield CA. They wanted over $1500 to fix this problem, which only cost $65 to fix. I wasted $40 on a used ECU because of their BS diagnosis, but that was still better than getting ripped off. (FYI, I called Barber Honda parts today to see what they charged for the O2 sensor and they quoted me $497. Unbelievable!)

I have a good used ECU if someone needs one!

David

 

That’s highway robbery! Glad you got it all worked out, but sorry the ECU didn’t help much other than letting you know that wasn’t the problem.