I have a 2003 EX and am having following probles:

1. The car shudders and sometime stalls, when I stop at light/sign.
2. While driving the car the gear indiacator in the instrument panen goes off (the green light by "D") and check

engine sign blinks, click-click sound comes from the grer shifter area, there's a small jerk and then gear

indicator light come back. This happens pretty frequentlty.

The car mech I have been going to since last 8-9 years first cleaned the throttle body, that didn't help.
Then they replaced the IACV and that didn't help much, except that the frequency of first problem reduced a great

deal.
Then they checked all the electric grounding and also replaced the master relay. That didn't help at all.

Now they are asking to replace the ECU. I am really confused and frustrated at this point.

Are they even looking in the right direction? Could ECU be the cause of all these issues?

Any help/pionters will be greatly appreciated.

Thanks

 

It is rare for the ECU to go bad. I think you should take your car to a new mechanic who has extensive experience working on Hondas.

Blinking of the CEL while driving indicates the occurrence of misfiring so severe that the catalytic converter can be damaged (see diagram below) -- so you don't want to run the engine very long under these conditions.

Take your car to AutoZone where they will read the CEL trouble codes free of charge. Post the CEL codes to get additional feedback.

 

I checked the codes already, since the CEL doesn't stay, no codes are set.

But I will take it to local Honda dealership today.

Thanks

 

You also might want to have the alternator checked.

 

It was installed about 4 months back. Brand new Denso.

Actually if I remember right, that's when this problem started, but I noticed it recently when it became worse.

Could it be related?

Thanks

 

You may want to check the alternator electrical connections (corrosion/damage) and whether the alternator belt is loose or slipping. Problems with the electrical system occasionally can lead to false CEL trouble codes.

Also check the battery and its terminals and connectors. They might be loose or corroded. Similarly check the ground wire from the battery to the body frame.

AutoZone will check the battery and alternator free of charge.

 

Took the car to dealership and they found no codes. Nothing new, as I had already told them that no codes are set. They couldn't replicate the problem either.

They said that the ECM software needed update though and they updated it.

This is becoming real pain now...

 

I agree you may have a fundamental electrical problem with the wiring around the battery or alternator, main fuse box, etc.

Also check that the backup power circuit is feeding the ECU. This is a separate supply that is always on so the ECU can remember codes and also fine tuning calibration factors in RAM. Without it the engine will run badly because it needs to recalibrate itself every time it is started. Also whenever the CEL comes on a code should be stored, and remembered after the light goes out, unless the backup power is not working. In that case the code will be erased every time you turn the key off.

On older models anyway the backup circuit was shared with the radio, and improper installation of an aftermarket radio could mess it up.

 

The problem was fixed at the dealer.
They could not see any error codes set my the ECM.

But there was an update available for the ECM, they updated the software. No other mechanical or electrical repair was done.

It's been 4 days now and I haven't seen the problem so far.

Strange, but the problem is gone.

Thanks all for your help here.