Sticky ECU Code 14

Hello, a friend's 1996 Honda City (with an engine almost identical to
the D16Y7, 4cyl SOHC manual) recently had an uncontrollable high idle.
The ECU said code 14 (IAC), so they replaced the IAC valve (3-pin,
rotary).

However it still keeps blinking the same code, and I tried resetting
the ECU (overnight!) and even pulling other sensors, but it keeps
blinking code 14, and won't blink any other error even when other
sensors are disconnected.

What could be the problem? Thanks so much.

 

I'm thinking a hefty vacuum leak into the intake manifold. That would cause
a high idle and make the ECU think the IAC wasn't responding because the ECU
had ordered a lower idle and the IAC wasn't delivering on that. A close
visual inspection of hoses on the intake manifold is a good place to start.
Cracks right at the ends are most common.

Mike

 

I'm thinking a hefty vacuum leak into the intake manifold. That would cause
a high idle and make the ECU think the IAC wasn't responding because the ECU
had ordered a lower idle and the IAC wasn't delivering on that. A close
visual inspection of hoses on the intake manifold is a good place to start.
Cracks right at the ends are most common.

Mike

 

Is the idle still high?

 

Is the idle still high?

 

Thanks for the responses.

Tegger, we haven't started the engine yet. The error code appears when
the ignition key is in the 'On' position. We've already tried leaving
the battery disconnected overnight to "clear" the code, we also tried
(in desperation) connecting the old IACV, but the code won't go away. I
also tried disconnecting the TP and MAP sensors, but it still blinks
"14" (IAC). I checked the resistance of the new IAC and one pair of
terminals read 19 ohms, all other pairs read open. Could it be a bad
ECU?

Mike: I wish it were, but the code appears even before we start the
engine. We haven't done that yet, because we're worried the ECU may be
bad.

Tomorrow I'm going to try disconnecting the same sensors on a Civic of
the same series (EK) and see what error pops up.

The owner is really worried, knowing the cost of a new ECU..

 

Thanks for the responses.

Tegger, we haven't started the engine yet. The error code appears when
the ignition key is in the 'On' position. We've already tried leaving
the battery disconnected overnight to "clear" the code, we also tried
(in desperation) connecting the old IACV, but the code won't go away. I
also tried disconnecting the TP and MAP sensors, but it still blinks
"14" (IAC). I checked the resistance of the new IAC and one pair of
terminals read 19 ohms, all other pairs read open. Could it be a bad
ECU?

Mike: I wish it were, but the code appears even before we start the
engine. We haven't done that yet, because we're worried the ECU may be
bad.

Tomorrow I'm going to try disconnecting the same sensors on a Civic of
the same series (EK) and see what error pops up.

The owner is really worried, knowing the cost of a new ECU..

 

dude, start the engine to see if you've fixed the problem first!!! if
not, /then/ worry about the code. and if replacement doesn't cure,
check the wiring.

also, make sure your coolant level is correct.

 

dude, start the engine to see if you've fixed the problem first!!! if
not, /then/ worry about the code. and if replacement doesn't cure,
check the wiring.

also, make sure your coolant level is correct.

 

Definitely, start the engine. The ECU can't know whether the IAC valve is
working until the engine is started. If it idles okay and the light is still
on, drive it a while or reset the code manually and see if it returns.

In the unlikely event the ECU is bad - they rarely fail unless they get
wet - a replacement usually costs about $75 to $150 US at a wrecking yard.
Prices vary that widely, so call around. It should come with a 30 day
replacement guarantee in case of an intermittent. If it works 30 days it
will probably work forever.

BTW - where is this located? I think all of North America was using OBDII in
1996, and 14 is the OBDI code for IAC valve signal.

Mike

 

Definitely, start the engine. The ECU can't know whether the IAC valve is
working until the engine is started. If it idles okay and the light is still
on, drive it a while or reset the code manually and see if it returns.

In the unlikely event the ECU is bad - they rarely fail unless they get
wet - a replacement usually costs about $75 to $150 US at a wrecking yard.
Prices vary that widely, so call around. It should come with a 30 day
replacement guarantee in case of an intermittent. If it works 30 days it
will probably work forever.

BTW - where is this located? I think all of North America was using OBDII in
1996, and 14 is the OBDI code for IAC valve signal.

Mike

 

Hmm. I think it's already OBD-II, but the CEL light is on so we jumped
the SCS connector, and the CEL blinked one long and 4 short blinks. Am
I reading it correctly?

 

Hmm. I think it's already OBD-II, but the CEL light is on so we jumped
the SCS connector, and the CEL blinked one long and 4 short blinks. Am
I reading it correctly?

 

Start the engine. Does it run OK?

What country are you in?

You won't wreck the ECU just by startng the car.

 

Start the engine. Does it run OK?

What country are you in?

You won't wreck the ECU just by startng the car.

 

Ah - I heard there were some versions that could be read as either OBDII or
OBDI, and this must be one of those. That should be the correct reading.
There is a manual for Japanese import OBDI reading at
http://www.iequus.com/downloads/manuals/3173_ICCR_E_14JAN03.pdf and Hondas
are on pages 16-25 of the PDF.

Mike

 

Ah - I heard there were some versions that could be read as either OBDII or
OBDI, and this must be one of those. That should be the correct reading.
There is a manual for Japanese import OBDI reading at
http://www.iequus.com/downloads/manuals/3173_ICCR_E_14JAN03.pdf and Hondas
are on pages 16-25 of the PDF.

Mike

 

We're in the Philippines (Southeast Asia). The car is a 96 City,
manual. The engine is the same in every respect to a D16Y7, except it's
only 1.3L, not 1.6. Hope we read the trouble code correctly.

Will try starting it tomorrow, will post back on how it goes..

 

We're in the Philippines (Southeast Asia). The car is a 96 City,
manual. The engine is the same in every respect to a D16Y7, except it's
only 1.3L, not 1.6. Hope we read the trouble code correctly.

Will try starting it tomorrow, will post back on how it goes..

 

Jumping the SCS connector reads out the ABS codes or the SRS codes depending
on which light you are looking at, NOT the engine codes. You need to read
the engine codes with an OBDII tester. ABS14 is left front wheel sensor, SRS
1-4 is short in driver air bag inflator..You can't flash engine codes on any
OBDII vehicle I know if.