Dear Experts,

I have a 1996 Honda Accord
2.2 VTEC engine
275K miles

In addition to some other issues I've mentioned,
lately the car is fast idling.

Before, when stopped, the warm idle
RPMs were 600 to 800 RPM.

Now, long after the car is warmed up, the
RPMs are 1200 to 1500 RPM.

In addition, I've got the P0401 error.
Exhaust Gas Recirculation Insufficient Flow
https://www.engine-codes.com/p0401_honda.html

This is odd, because when I changed the
fuel injectors, I also cleaned out the EGR
passage as recommend by Eric the Car Guy.

But I've still got the P0401 error after
cleaning the passage.

The P0401 error may or may not be related to the
fast idle.

Does anyone have any experience with either of
these symptoms? If so, please tell the
secret as the problem, and solution(s).

Thanks

 

An update

A few online posts and a mechanic
suggested that the issue may be a bad
Idle Air Control Valve (IACV)

Honda 16500-P0A-A01
https://www.hondapartsnow.com/genuin...0-p0a-a01.html

And, that two hoses with coolant connect to the valve.


Turned out that the coolant was really low.

Today, I filled up the overflow tank, and it seems to help.

Soon, I'll also fill up the radiator, when it's cold,
and see if that solves the issue.

 

Another update

Added more coolant to both the radiator and
overflow tank

The car still fast idles, but it is
better than before. Sometimes,
after it has warmed up, the RPM
drops to less than 1000 rpm.

 

have you changed your egr valve? Go buy one with a warranty at pick a part

 

Thanks

I'd checked the EGR value in September
less than 2 months ago

The vacuum was working fine

Any other ideas?

 

You need to bleed the cooling system and get all the air out.

Did you replace or reuse the EGR gasket?

 

Update:

Over the Winter, in the cold weather, every few dozen miles,
Keep getting code:
P1491
EGR valve lift insufficient detected

In the cold weather, the car also idles fast, about 1500 RPM,
Then slower, about 1000 RPM
Jumping up and down between the two..

But not the old 600 RPM

Suspect that I need to change the
Idle Air Control Valve (I.A.C.V.)

Does anyone have any experience?

Thanks