kcirdnek

Okay, I went to AutoZone on Saturday to have them check the OBDII. The check engine light has been on for awhile now. There were five different codes that came up. These are the codes that came across:
P1491 Secondary switch solenoid circuit malfunction.
P0401 The PCM has determined that there is insufficient flow in the exhaust gas recirculation system(this code actually came up twice).
P1457 Unable to pull vacuum in tank.
P0420 The PCM has determined that the catalyst system efficiency for bank 1 is below threshold for the current engine operating conditions. Bank 1 identifies the location of cylinder #1, while bank 2 identifies the cylinders of the opposite bank.

What do these codes mean the the average person?

BTW, I have a 1998 Honda Accord EX-V6.

JimBlake

My list (for '98 4-cyl...) says:

P0401 = EGR low flow rate.
P1491 = EGR valve insufficient lift.
The exhaust-gas recirculation passageways in the intake manifold can get clogged. I suppose that's true for V6 also? The Helm book has some specific tests to check it out, but I don't have the V6 book.

P1457 = EVAP system leak, control canister system.
There's a half-dozen valves, bunch of vacuum tubing, a filter, & a charcoal canister under the back seat. Something's not airtight... The canister vent-shut valve is a common failure (mine did) but this is another case where there's several pages of checks in the Helm manual to find which part is actually bad.

P0420 = Catalyst low efficiency.
If you're lucky, this one's a fluke & it'll go away when you fix the others. Otherwise, what's your mileage? I think the emmissions system warranty is 8yr/80k miles.

kcirdnek

My car has over 199000 miles on it. Probably hit the 200000 next month.

The AutoZoner told me that the P1457 code, unable to pull vacuum in tank, was just the gas cap. He also told me the P0420 code, the PCM has determined that the catalyst system efficiency for bank 1 is below threshold for the current engine operating conditions. Bank 1 identifies the location of cylinder #1, while bank 2 identifies the cylinders of the opposite bank, was the O2 sensors.

What do you think? Could he be right or was he just calling out something?

He had no idea what the other two codes meant.

I was told awhile back that my catalytic convertor was bad, could that be one of the codes?

In your reply, you called out the EGR Valve twice, do you thing it needs replacing?

JimBlake

Any code higher than P0999 doesn't mean the same thing for different carmakers. They can read the code number, but beware about their explanation for the reason.

I had P1457 last year, & AutoZoned told me it was because I didn't tighten the gas cap. I said thanks & went home to read the REAL reason in my repair manual. In fact, a loose gas cap would set P1456.

Check out this thread. Down a ways I posted some of what I did. No guarantees about what's different for a V6, but most of this stuff is back near the gas tank.
https://honda-tech.com/zerothread?id=748876

You've got 2 different codes about the EGR. I don't think you can tell from the codes whether its a sticky EGR valve, clogged ports, loose vacuum line, or a broken wire. That's why you test the different components of the EGR system to find the problem.

Bad catalytic converter will cause P0420. The 2nd O2 sensor measures how the catalyst is working, so it's possible that's bad. I'm not sure how to tell the difference between a bad cat vs. a bad 2nd O2 sensor.

Bank 1 or bank 2 is just for cars that have dual exhaust all the way (V-8 rwd?), so there's 4 O2 sensors. Not sure, but I think an Accord V6 only has one catalytic converter, so bank 1 is all there is.

Yvette

Dear Mr. Jim

I have a 1999 Honda Accord... 4 cyl. Engine light came on, so I hooked up the OBD2 scanner.. and it gave me the reading " P1259 " "Fuel Air Metering"
I looked on the Actron Wb site, and the couldnt give me any further info on this, Can you please help ?? Thanks so much, Yvette

JimBlake

P1259 is something to do with the VTEC system. I'm not sure if it's the VTEC oil pressure switch, but if you're low on oil that might be a good guess.

Maybe I can remember to look it up...

Yvette

Oh Jim, would you please do that for me..... ya know.... maybe it IS time for an oil change.... I am usually good at keeping on-top of that sorta thing.... Thanks so much, Yvette

JimBlake

VTEC uses oil pressure to work, so check that first. Make sure there's enough oil & it's not old & thin or cruddy.

It says first check your VTEC oil pressure switch. Green plug, forward & down from the distributor. Unplug it, use a multi-meter, there should be continuity between the two pins when the engine's off. If not, you need a new switch.

One of the wires should have continuity to ground. The other goes to the ECU. Leave it unplugged, turn on the car (I don't think you have to start the engine). You should measure battery voltage across the two pins of that green plug. If not, look for breaks in the wiring, somewhere.

Then you can take the whole VTEC spool valve off, check if it's full of crud. There's a screen in the gasket, maybe that's plugged?

If you get this far without finding anything wrong, you check the action of the VTEC rockers in the valvetrain. For that you'll want a copy of the Helm repair book 'cause I can't explain it in a few paragraphs.

Yvette

Hey Jim.. You were right..... I baught a shop manual and it said ALL the same things you said.... I didnt go as far as take the switch off and check the screen, (boy, are those bolts hard to get to , or what ?) But I did check the wires , like the book ( and you ) said...... Fact of the matter.. Changed the oil........ fixed the problem !! Go figure..... LOL.... Thanks for all your help..... Yvette