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Gary, ASE Certified Technician
Category: Honda
Satisfied Customers: 1122
Experience:  Senior Technician
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01 passport P1340 I've cleaned grounds @: alt bracket, twin

Customer Question

01 passport P1340
I've cleaned grounds @: alt bracket, twin at batt wheel well, and the 3 on the intake. Cleaned connectors w/ electronics cleaner.
New: boots, plugs, intake gaskets, and wiring looks fairly decent being here in AZ.
Freeze frame keeps showing the DTC at low engine (800-2000 rpm) & vehicle speed (mostly 0 but one at 18 mph) PLUS B2 LTFT is ~22%. ?? Both B1 & STFT are @ 0 but LTFT B2 is rich.
Unplugged one O2 at a time and looked at live data to verify none are swapped.
What would cause the PCM to "rich" the Long Term while Short is 0??
ALLDATA diag chart says check harness from PCM to ICSS at QC line harness connector. I know PCM, but what/where is "ICSS at QC line harness"?
Just Ohm it out each line or is there some other check?
Submitted: 1 year ago.
Category: Honda
Expert:  Anthony replied 1 year ago.


Is the compression good and no clogged cats?

Customer: replied 1 year ago.
compression should be good vehicle runs well (~140k mi), plugs burn perfectly, and cleared: p300/301 via valve cover gasket change, p420/430 with new cats. New plugs are Denso k16prp11.
Pings under accel and uphill, but can give more peddle to silence.
Customer: replied 1 year ago.
engine has ~140 k, chassis has 270k.
Found rust on 3 coil tips and boot spring tops-replaced all boots and #6 is a shorter boot.
That's B1 STFT/LTFT and B2 STFT are at 0, while B2 LTFT is hanging at 22% on repeated Freeze Frame data.
Expert:  Gary replied 1 year ago.

Hi there,

Some more ideas.

Have you checked the cam timing?

The LTFT and the pinging says to me the valve timing is wrong on bank 2.

And what cats did you fit?


Customer: replied 1 year ago.
B2 LTFT appears, for now, to be coming down to more normal levels since B12 Chemtool in gas.
At 7.8 with STFT -1.8, so its trending down. Stuck closed injector(s)? Possibly gunk from tank because B2 inj are on the tank side of fuel rail. The 1340 comes mostly during Open Loop at start up/low rpm.Even though under the hood, being here in Phoenix in summertime, B2 is on the sunny side of the truck all day (I'm unemployed right now), thus causing the gas in fuel rail/B2 injectors to caramelize/stick more readily?FYI-I checked all the related harness wiring to/from PCM, coils, injectors, and ION-all good. The only oddity was all B2 injectors at 13.9 ohms resistance and the B1s were all at 13.1. I don't see roughly 1 ohm making much difference. Yes?ALLDATA is saying it is the ION module. I can see the ION affecting timing, but not B2 injector pulse length. Yes? Especially the Long Term FT. Wouldn't any ION influence be in Short Term FT first? Or, at the very least it's affect seen in both at the same time.On the cams, I have not. I realize that cams can hop teeth, but nothing has been done with the cams, timing belt or near/related to both. Plus, these cams have the diagonal teeth that I thought were much harder to jump. It's in a truck and I take care of my machines by not over-revving at any time. Wouldn't I see bad cam timing in some way at either O2s? Because our truck runs well, w/ no other codes, except for pinging and the stats on LTFT.Cats-Magnaflow Universal fit. The same unit on each side. P420/430 cleared immediately.S1 O2s are responsive and ~2 years old. S2s are brand new.
Expert:  Gary replied 1 year ago.

That's all very good info, and looks like you know enough to nut your problem out .

Great when we can be on the same page.

Yes you may be correct with varnish buildup on the B2 injectors, since your additive has made a difference.

As an experiment, I would swap all the injectors from B2 to B1, and then see if the B1 trims go high like B2 is doing now.

Is double work, but you'll know.

If the trims do swap over, then have the injectors ultrasonically cleaned.


Customer: replied 1 year ago.
The P1340 is preventing us from getting emissions this month and is our main reason for the "right now" status.1. Does the ION module have the ability to adjust the injector pulse width?2. How does an ~1ohm difference between banks affect the PCM?3. Does this 1 ohm difference tell us anything about the injectors (age, quality, varnish etc.)?4. The 1340 seems to show up mostly at morning startup. Can an errant ECT sensor shift the PCM's calculations enough to create the 1340? (I plan to pull the Live Data b4 startup to see if the reading is excessively off).5. What Ohms should one read on coils?Oh yeah, fuel pressure checked good and NEW: fuel filter, O-rings/seals on all injectors, fuel pressure regulator, EGR (had DTC it cleared), coil boots and both upper/lower intake gaskets.
Expert:  Gary replied 1 year ago.

Hi again,

Did you fit the factory recommended spark plug and gapped correctly?

Here is some info about spark plug function when not firing:

I would think that the 13.9 ohms versus 13.1 ohms would make the injector a fraction lazy, which then has the closed loop correction adding fuel (+ fuel trims), strange that all 3 on one bank read higher than the other bank.

I would still swap them bank to bank for another test.

So other than your P1340, does it now run ok, and have the fuel trims evened out as yet, or are you now willing to swap the injectors bank to bank?