EGR and P0402 code

[Dale]

Hi. New to this forum and gotta say I'm impressed with the general knowledge here Our '95 Camry V6 LE auto. has 215k kms on the clock and it has been well maintained over the years -- such a reliable product that I'm hesitant in replacing the car with anything more current. Anyway, the ECM recently threw OBDII code P0402 -- excessive EGR flow. With that code the only other signs of odd behaviour is power surging which makes it feel at times like it's stuck in low gear ..or the power switch on the console is depressed -- no apparent hesitation or rough idling though Through info on this forum and as it was the easiest spot to start, I began by checking the VSV (vacuum switch valve) under the top engine cover. The valve is whistle-clean inside. The specs call for a resistance of between 33~39 ohms across the 2 solenoid terminals. Unfortunately, it reads infinite -- circuit's open. I double checked with another known working vacuum switch valve (from under the engine cover) and sure enough it reads within specs (34.5 ohms). So I guess I should stop testing there for now as this vacuum switch is hooped electrically and will need to be replaced. I figure going to a wrecker may help with the expense of replacement. Can anyone tell me which models (and maybe DoM) of Toyotas that have the same vacuum switch? -- they look like they may be a relatively common item for the years involved.

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[toyomoho]

Years 1992-1996 were the same generation.

The engine was used until 2001.

The switch works by changing the routing of the vacuum coming in from the "T" port to either the side port or the filtered port (on the "T" side).

Bring the old switch with you to compare plus the meter.

[Dale]

Originally Posted by toyomoho

Years 1992-1996 were the same generation.

The engine was used until 2001.

The switch works by changing the routing of the vacuum coming in from the "T" port to either the side port or the filtered port (on the "T" side).

Bring the old switch with you to compare plus the meter.

So, this switch was used in all 1MZFE engines through all makes?

fyi, I guess this switch has been on its way out for quite a while as sometimes it took weeks or even a few months before the mil came back on. It's only lately that the fault has been a steady pita.

I've removed the switch for now (until a suitable part is rounded up) and just temporarily connected the 2 vacuum hoses together -- I don't think this will this cause damage to any parts of the engine, cat converter or O2 sensors ..can you confirm this

[toyomoho]

Ops, if 1MZ-FE the engine was used until around 2005ish.

I don't know if the same part was used throughout the years. The Rockauto website my list the part, if so you can compare part numbers between years.

If you bypass the VSV, the EGR system will be ON all the time. This should not damage anything but the engine may not idle very well. EGR system turns off when engine cold, at idle, full throttle, RPM above 4200ish, light engine loads.

[Dale]

Originally Posted by toyomoho

Ops, if 1MZ-FE the engine was used until around 2005ish.

I don't know if the same part was used throughout the years. The Rockauto website my list the part, if so you can compare part numbers between years.

If you bypass the VSV, the EGR system will be ON all the time. This should not damage anything but the engine may not idle very well. EGR system turns off when engine cold, at idle, full throttle, RPM above 4200ish, light engine loads.

Thanks, Joey -- Rockauto doesn't list the VSV at all. It would be nice to be able to find a site that one can plunk in the part number and have it cross reference other models and years


Amazingly, the engine seems to run smoothly, albeit with a surge ..it can jack-rabbit with the touch of the gas pedal. This is part of the reason I have ignored the problem light until now that I have more time for it.

Gonna check out a wrecker this week and see what they have for replacement. As there are 3 switch valves on the v6 (for different apps), will any of those other switch valves work in place of this particular one -- just in case I can't find the correct one ..or it's damaged on-site?

Any other related stuff I should consider grabbing while there?

[toyomoho]

Manual states possible problem areas are:

EGR valve stuck open
VSV or wiring
Computer (Seldom goes bad)

[Dale]

Originally Posted by toyomoho

Manual states possible problem areas are:

EGR valve stuck open
VSV or wiring
Computer (Seldom goes bad)

Gotcha -- thanks.

I managed to find a used VSV and replaced it (it's solenoid section was open) into the EGR system. I guess I should have just left the MIL light on and let the car cancel when it ran through its routine, but I forgot that step and manually cancelled it via the OBDII interface (laptop). So far, so good -- no dash light has come back on

[toyomoho]

Great!