P 1580 throttle motor bank 1 electrical malfunction ????

[Bud Osbourne]

Finally broke down & bought a scanner.
As indicated in my previous post (high mileage Golf III...........), my Golf would NOT start after sitting for more than 24 hours. My new scanner found fault code "P1580 throttle motor bank 1 electrical malfunction".

My question: Whut dat mean?

After scanning, I got the car to start w/o any difficulty, but the idle was REAL low. Then, I mistakenly hit the "erase" button and the idle shot up to 2,000 rpm, but "hunting" (1800-2200 approx.). Shut the engine off, then re-started after 30 seconds and all is well. WTF!?!?!?!

So, if I can figure out what that fault code means, maybe I can get back to normal operation.

One more thing: after charging the battery for the past several days (no shit....several days @ 2 amps), the scanner showed battery voltage as 12.1. After several minutes with the engine running, it showed 12.9 volts. I know my battery charger is working well, so I suppose I need to think about a new battery (terminals are ALWAYS kept clean and free of corrosion).

[ps2375]

year of car would help, as the OBDI cars only had a TPS in TB, where the OBDII cars have an actuator motor that controls TB for idle speed (motor does not have an ISV). You might try cleaning the inside of the TB, they tend to get dirty from oil and stuff coming thru the PVC system off of the VC.

A better but more costly scanner would have been a VAG-Com cable, much more function and you get the "real" code, but you can still go to here:http://wiki.ross-tech.com/wiki/index.php/Main_Page, and get a valid translation.

And I have seen many a time where an old under voltage battery will cause these cars to run very poor, and just a replacement with a new battery makes a dramatic change in how the motor runs. And if your battery is more than 5yrs old and it is causing you issues, you've gotten your money out of it and it's time to replace it. I have gone further on a battery in the past, but it was on a CIS car and there were no electronics on it, so there was nothing to be effected.

[Bud Osbourne]

As mentioned in the other topic thread (you were the only one to answer that one, too....Thanks!), it's a '98 with 375,000 miles on it. It's always been a bit pissy about starting, after sitting for a few days (had it since new), but has gotten really bad about it, this year.

I'll have to check my log book to see when I replaced the battery, last. I'm thinking it may have been December of 2010 and I'm due to buy a new one. I used to get more than 5 years out of batteries, in this car, when I used to drive it a minimum of 100 miles per day (all highway/open road). Now that I'm semi-retired, it sits a lot, so it stands to reason an old battery wouldn't hold up too well.

I'll clean the TB real well and see if that makes a difference, although I seem to recall doing that last summer. The engine still doesn't burn more than a 1/2 qt of oil between oil changes (same as always), so it's not like there's a problem with blow-by in the breather system.

The scanner I bought is configured for VAG cars, but I'm afraid I need to get a printed copy of the instruction manual, so that I can teach myself how to use it more effectively.

Thanks for your help & suggestions. I'll let you know what I find & how it turns out.

[Bud Osbourne]

Update time. Well, since I got it started a couple of weeks ago (as mentioned above), it's been starting & running just fine, since I've used it every day.

Today, however, after driving it yesterday, it started with a heavy misfire. I wasn't expecting that and I let it die. So, she's a no start, again.

Put the scanner on it and it showed #4 cylinder misfiring. Since I had some time on my hands and it's not cold, today, I decided I'd pull #4 spark plug and see what it looked like. BTW, I'm the guy who always advocates checking the basics, FIRST........... Anyway, I confess to being a bonehead and NOT checking the basics, first. I found the #4 spark plug to be only finger-tight (once I finally wrestled the plug wire off, carefully, so as not to destroy it....GD modern cars!!!). Although the plug showed good color, the gap was over .060"!!! The manual calls for .024". Talk about STUPID! I go to the trouble of keeping a very detailed maintenance log book, but neglect to review it to see when I last replaced plugs & wires.

So, although this (spark plugs) may or may not be the answer to the difficult starting (after sitting) riddle (but I suspect it has a LOT to do with it), it's one of the basics which I should have attended to at the first sign of trouble.

I HATE when I don't follow my own, hard-learned rules and have to re-learn them. What really pisses me off is that massive gap makes the coil work a LOT harder, which means it will fail, sooner than normal.

The battery? Oh, yeah. Well, I ordered a new Decca, but, due to the holidays and some screw-ups by my local Decca dealer, I don't have it, yet. Scanner showed the battery at 12.5 volts, today. Given that HUGE spark plug gap, plus the power needed to crank the engine, I can imagine there were some VERY weak sparks being produced.