How to clean a VW throttle body 2.0 for the dreaded P1582 code. MKIII ODB II Only (96'-99')

What is P1582?

It's a code, triggered by the cars computer (ECU) that turns on the check engine light (CEL). It means "idle adaptation at limit". The
cars idle is controlled by a small motor. As the car gets older (read dirtier), the ECU "pushes" the motor a little further out to let more air into the engine. - Before you do this Go Read This Link - Stan brings up some good points

Eventually the motor is at the extent of its travel, and the dirt buildup is too much, and the ECU cannot adapt to make the idle higher
– so it turns on the CEL.

Ahh, P1582, you suck.

The VW factory shop manual says "replace the TB", Bentley gives no mention of it, and other "professional" aftermarket tech manuals tell you to change the oil.

Here's a scan from the VW manual!

None of that will fix it!!!! Unless you have $600 to shell out for a new TB!
So.. What needs to be done, can you do it yourself?

Of course you can!!

Q - I read that I need to "realign the throttle body". 

A - No, not on a MKIII OBDII car.  That is only needed for the MKIV and Beetle platform vehicles.



A few rags;
An old toothbrush; (I mean it, your never going to use it again)
An O2 sensor safe throttle body spray (avoid the "old standby" Gummout, or Gum cutter)  (I really like the 3M stuff, buy it online, most GM dealers carry it as well!)
Flat head screwdriver
Safety Glasses
10mm wrench
1 hour for a 1st timer.

1 – Wait for the engine to cool down. Try on your safety glasses. Ohh, don't they look fancy!

2 – Open the hood, and look to the left of the engine compartment (That's the passenger side in North America)

3 – Using your screwdriver, follow that big rubber "elbow" up to where it connects from the air box (air filter), and then to the engine
intake. That engine intake is where we are going to work.

4 – Remove the two clamps on the big elbow. Just loosen them up, don't undo them all the way.

5 – You may have to use your screwdriver to pop off this hose, its not a big deal, but don't yank with all your might.

6 – Everything off? Good take that elbow off. If there is oil inside of it, wipe it out with a rag, don't freak out.

7 – You'll see a cable on the side of the throttle body (yes that's its name), pull back on the cable and you'll see the butterfly valve
move. This is what happens when you step on the "gas".

NOTE: Make sure NOTHING falls in there, if it does, its going to get chewed up by the engine!

NOTE II: Some more advanced folks may wish to remove the 4 Allen head bolts and remove the TB to get a better "cleaning" done to it. IMHO its not needed, but can make this job a little longer, and AND you'll want to replace the paper gasket (available from your VW dealer.. for a  buck or two) behind the throttle plate. Some people get lucky and can reuse the gasket. If I were going to do it this way, I'd have one on hand.

8 – Place a rag under the intake (to catch drips). Hold the butterfly open with one hand, and then give it a good 10 second spray.

9 – Use the rag, and wipe out the butterfly valve and "dirt".

10 – Repeat a few times, use the toothbrush to knock out the old dirt and grime, get the brush as deep as you can.

11 – DO NOT to spray the "whole can" into the engine!! If you do you run the risk of "hydro locking" the engine. If you do steps 9 and 10 more than FIVE times, try to start the car. It will clear the cleaner out. Don't worry the car is not going start, or be happy. This is normal. Just crank it, it will stumble and stall. Its OK..

12 – Once done, hook everything back up. Remove the rags. Make sure all of the lines are plugged back up.

13 – Start car. It's going to start "hard" in the sense that it may smoke some, and make some commotion. This is normal. If the CEL is still on, don't worry, we'll take care of that soon enough. Let the car warm up, and idle.

NOTE: Throttle Body Alignment (TBA) (Requires VAG.COM), in place of pulling the battery cable as per step 14.... "The best way.."

Turn the key on but do not start the car.

* [Select]
* [01 - Engine]
* [Measuring Blocks - 08]

Enter Group 098

* [Go!]
* [Switch to basic settings]

Once you do this you will see the top right display say ADP RUN. The TB adaptation is being done as soon as you switch to basic settings. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.

* Click the [Switch to Meas. Blocks] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!

14 – Final step: Unhook the NEGATIVE terminal of the battery. Let the car sit for 10 minutes.

NOTE: Make sure you have your radio codes handy (SAFE MODE). Also the horn may honk (alarm goes off) when you hook the battery back up… wear a diaper. You'll have to unlock the car WITH the KEY in the DOOR to turn it off.

This will reset the idle and ECU.

15 – Enjoy your car, it should idle like it was new, and may even start a little quicker!