Results 1 to 8 of 8

Thread: P0491 & P0492, diagram for secondary air pump lines. '02 325

  1. #1
    Join Date
    Jan 2006
    Location
    Provo Utah
    Posts
    50
    My Cars
    Audi A4, BMW 325i

    P0491 & P0492, diagram for secondary air pump lines. '02 325

    I keep getting the dreaded P0491 & P0492 on my 2002 325i. Before doing anything serious I was wondering if anyone knows of a diagram of the lines to the pump etc. If there is a break in the line, I'm wondering the best way to find it.

  2. #2
    Join Date
    Jan 2016
    Location
    Ca
    Posts
    6,981
    My Cars
    2001 525it
    Well you have the pump, line, vacuum hose that go around the back of the head to the rear of the intake manifold where there is a switching solenoid,,that's it.

  3. #3
    Join Date
    Dec 2013
    Location
    Chicagoland area
    Posts
    4,372
    My Cars
    EXOTICS
    M54 or M56?

  4. #4
    Join Date
    Jan 2006
    Location
    Provo Utah
    Posts
    50
    My Cars
    Audi A4, BMW 325i
    Not sure if it is M54 or M56. The air pump is on the front left of the engine if that helps.

  5. #5
    Join Date
    Dec 2013
    Location
    Chicagoland area
    Posts
    4,372
    My Cars
    EXOTICS
    Need the last 7digits of your VIN#

  6. #6
    Join Date
    Jan 2016
    Location
    Ca
    Posts
    6,981
    My Cars
    2001 525it
    The m56 engine has a hinged engine oil cap that you can't remove when adding engine oil the m54 has the normal oil cap you can remove

  7. #7
    Join Date
    Jan 2006
    Location
    Provo Utah
    Posts
    50
    My Cars
    Audi A4, BMW 325i
    The back of the engine is completely inaccessible. Are there any trick to getting back there to see if the lines are cracked or disconnected? Does the switching solenoid go bad often? How do you access it?

  8. #8
    Join Date
    Jun 2017
    Location
    Denver, CO
    Posts
    264
    My Cars
    325xi; 740i
    Pop the cabin filter assembly off, there's I think 4 torx bolts at the top undo those and it will pop off. Right side heat shield would help a little too, lift the gasket off, lift the brake booster line and the wiring harness out and there's two clips holding it in.
    New Daily:
    2011 Audi A6 Avant 3.0T prestige. 1 of 368

    ----FOR SALE-----
    04 BMW 325xi 143k


    The Fun car:
    94' BMW 740i 308k miles

    Fresh 72k mile engine with all new seals. True E34 Manual Trans Engine Harness. 6spd Transmission Swap, Getrag 420G. RHD LW Single Mass Flywheel. E39 M5 Clutch. E39 M5 Shifter. Factory Car Phone. Factory 6CD Changer. Factory Electric Sunshade. Not So Factory Factory Electric/Heated Rear Seats. E38 Heater Valves. E43 M5 calipers/brakes

    Sold:
    1996 Oldsmobile Aurora; 194k miles but with a bad paint job and dented fender resulting in a payout to buy the 740i

Similar Threads

  1. E39 Secondary Air Pump -- Fault Codes P0491, P0492
    By napalirick in forum 1996 - 2003 (E39)
    Replies: 26
    Last Post: 01-19-2019, 10:27 PM
  2. P0491 P0492 Secondary Air Pump & Valve E46
    By rpm694 in forum General BMW Mechanical Help sponsored by RM European Auto Parts
    Replies: 8
    Last Post: 04-13-2011, 01:30 PM
  3. Replies: 1
    Last Post: 12-18-2010, 07:10 PM
  4. electrical solenoid for secondary air pump
    By fish4stripers in forum 1991 - 1999 (E36)
    Replies: 2
    Last Post: 04-30-2009, 08:13 AM
  5. Need wiring diagram for E38 air pump. Anyone?
    By mihai77 in forum 1995 - 2001 (E38)
    Replies: 12
    Last Post: 10-14-2006, 04:45 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •