EGR Valve Diagnostics

To check if EGR is working bad (not how bad it working), you can follow this procedure.

Using HDS, go to PGM FI module and then to Snapshot.
There you should select high speed mode and select following params to record.
- Engine Speed
- VSS
- ECT Sensor
- Map Sensor
- TP Sensor
- EGR L Command
- EGR LIFT

Procedure:
With the engine completely warmed up, have an assistant drive the vehicle while you operate the
HDS. Drive the vehicle between 65 and 90 km/h on a smooth road. Apply light throttle with the
transmission in 5th gear (between 1,500 and 2,000 rpm). If hesitation is felt, select the Snapshot Manual Trigger button.

After snapshot sample is saved, you can review in garage.
Plot line graph on EGR L Command and EGR LIFT.

And this is a good EGR response.

This is BAD or EGR clogging response.

From: Honda Service Bulletin 05-026.

36,400 km | 2Y 4M