Category Archives: cars

Audi Q7 4.2L Base BAR engine codes(Revised)

The car started to idle rough, sometimes it would shut off, other times it was difficult to start. The EPC and CEL(check engine light) were both on. To prevent the car from laboring too much I would have to keep it in neutral at stops. I updated this posting in red. 

The following two codes(P0171, p0174) were remedied by replacing the PVC valve that is located near the firewall above the throttle body. You will need a T27 or T30 star bit to get it out. It is in a tight space. Took me about 45 minutes. Under further inspection these codes are caused by a split hose. A leaky vacuum hose connected to the intake. 



The following code(P0129B) was remedied by bending the metal contacts inside the connectors to the two high pressure fuel pumps. Once I had gotten this code previously because of a blown fuse in the engine bay fuse box located under the hood, on the drivers side just below the windshield. It was one of the blue 15 amp fuses. Its best to check the fuses and connectors before replacing these high pressure pumps because they are expensive. This took about 2 hours of trail and error, swapping relays, testing the regulator/solenoid coil continuity, battery connections, etc. After replacing my High Pressure Fuel Pump at the tune of about $300 I found this issue is related to the solenoids. Under the driver’s side wind sheild wiper there is a fuse box. One section is easy to open with plastic knobs, the back of it has to be removed using torx bits. I saw a solenoid number 614 in both sections. I swapped them around and this code went away.


The following (P0300)code was remedied by changing the PVC valve, the ignition coils and spark plugs. The issue arose because the bad PCV valve caused oil to build up in the spark plug wells and reduced the quality of the connection between the ignition coil and spark plug. I could have simply cleaned the connectors on the coils and the plugs and this would probably have been good enough. I would suggest using a lot of dielectric grease when putting the coils in as it keeps some of the motor oil from getting into the space between the coils and plugs. I forgot to put grease on the ignition coil harness connectors…… Before buying a whole set of ignition coils. I would try to clean the connectors inside. This was caused by the solonoid mentioned above. 


I found the best deal on the OEM NGK spark plugs  and no frills ignition coils on I cant recall where I purchased the PVC/breather box as it took me a year after buying it to install it. If you have the time and the freedom(#MGTOW) just address a CEL/EPC light immediately or other problems will develop. Those of us on the plantation do not have that luxury and end up spending thousands for the dealer to do a simple fix.

If you need to access Qudi Q7 4.2 Manuals I found a few by digging around online and have uploaded them here: Audi Q7 4.2 Manuals

Featured photo: Tennen-Gas [CC BY-SA 3.0 (

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Unrelated to fanance kinda.. Volvo S80 2.9 Alternator change

Just got my first European car Swiss to be exact. I have had Japanese and Korean so I am familiar with metric bolts. Never had a car over 4 cylinders until now though. I find I prefer the expendable nature of small 4 cylinder economy cars as I am so delicate with this one. Its a used Volvo S80 2.9 non-turbo. Recently the car would not stay running unless it was connected to another running vehicle. I took the battery to Autozone for a free test and it passed. Going through the forums and asking for help eventually got the alternator out for a free test and it failed. So that was the problem. The dealership wanted over $600 for the alternator and I got one from Ebay for $50 plus fees. Popped it back in and got back on the road. This is unrelated but I found the instructions on the forums to be somewhat inaccurate.

1. Disconnect the battery terminals(10mm and 12mm bolt)
2. Remove the cover from the computer box and the outer cover
3. Use a flat-head screwdriver to remove the plastic cap from the tensioner pulley.
4. Rotate the pulley nut now visible clockwise(14mm bolt)
5. Pull the belt off while releasing the tension from the belt.
6. Remove the plastic cap from the positive terminal on the alternator(13mm)
7. Remove the three bolts from the power steering pump(12mm)
8. Remove the 2 bolts that are at the top of the AC compressor(12mm)
9. Loosen the 2 bolts at the bottom of the AC compressor(12mm)
10. Remove the bolt holding the top of the alternator(12mm)
11. Remove the water hose at the end to the Radiator(7mm)
12. Remove the bolt from the dipstick hanger(10mm)
13. Pull the alternator out(hard) Be careful not to break anything while forcing it out.

Autozone will sell you a cheap alternator about $190+ without a pulley. You have to remove the pulley by spinning the bolt clockwise(i really mean clockwise)(24mm)with an impact wrench. Or a 10mm star tool with a special open ended 24mm wrench. There are 2 different amps available. 120A and 140A so have it handy when you visit the parts store.

Or just buy a used alternator on Ebay as the dealership will charge 500 for the alternator unit only. I got one from Ebay for $50, and it came with the pulley.

Also you could simply order a regulator(Bosh or Chinese generic) which comes with the brushes inside for $20 to $50. Swap out the old regulator and the alternator will act like new.

Photos pending.

Now for something more related. Buy shares in Pep Boys(PBY) hold and sell at the end of spring. The summer compels long distance trips, dates, racing, car shows, car sales. Its also income tax return time.