p0401

  1. Bambusiero

    EGR Vacuum Modulator - Sensitive Functional Bench Test & Alternative Part Numbers

    I've been getting intermittent P0401 error code (Insufficient EGR Flow), so checking the vacuum modulator using the FSM test procedure. Apparently, I can't tell the difference between air passing through to the filter side "freely" and "with strong resistance". So - convinced the modulator was...
  2. Str8Razor

    97 LX450 Flashing Check Engine Light/ Vibration

    Truck has 195k miles on it and s***ty valve seals, Left for work this morning, accelerating through the gears and all of a sudden i get a heavy vibration and the check engine light starts to flash, truck was not happy and vibrating considerably over 2100 rpm, seemed to go away or calm down a bit...
  3. O

    p0401 part numbers

    Can someone provide me with the part numbers for a complete p0401 repair (intake gasket, throttle body gasket, vsv, vacuum hoses....and anything else I will possible need)?? I sure that info is here somewhere but I cant seem to find it. Thanks
  4. toyteg08

    Quick question - P0401 and knock sensors

    I searched, but didn't find much of anything. Is there any way at all possible for a bad knock sensor to cause a P0401 code without throwing a P0325 or 330 code? Back story: completely took off intake manifold to have hot tanked, broke connectors on TVV and rear knock sensor when unplugging...
  5. shack

    My P0401 Experience

    I recently have been battling the dreaded P0401 and ordered an OEM VSV with hopes I'd be able to replace it following the thread below. Seems easy enough right? Job only took the guy that wrote the steps about an hour. Here is his link and steps. RMLCA - Rocky Mountain Land Cruiser 4x4...
  6. BrooklynFJ80

    P0401 fix leads to bad stutter

    So I did all the work needed. See previous post 'this is what p0401 code looks like'. Idle now struggling and not smooth as before. Truck readjusting to more airflow? Should I disconnect computer and rehook up? Amy other ideas?
  7. BrooklynFJ80

    This is what P0401 code looks like.

    So I decided to just tackle all of this and get it done. Thanks to Onur for the parts. This is what 20yr old vac lines, manifolds and ports looked like inside. Replaced modulator, vac lines, check valves, etc...
  8. 40thSagePearl

    In need of some OBD diagnosis help.. P0171 and P0401

    well here is another one of these threads lol
  9. A

    Dreaded P0401 EGR on...and off...and on...and off...

    A year or so after head gasket replacement, and getting the head cleaned and having the EGR port cleaned out, my Lexus finally turned on the 'ol pop the hood and make sure the engine is still there' light. Scanner shows Insufficient EGR flow, but the truck runs fine so I ignored it for a week...
  10. W

    EGR Vacuum Tube Routing

    I've got a P0401 on my 1995. Had someone look at it and they suggested replacing the entire system essentially...the EGR valve, VSV, temp sensor. I checked it out today and noticed that there are a couple of open lines that have nothing connected to them. Upon comparing to other pictures, I...
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