Got flashing MIL while accelerating on an uphill following a slowdown

[mlt]

Over the past week I got twice this problem, so it became a concern. After Malfunction Indicator Light flashes a bit, it goes away and no code is left.

Here is my assumption how it happens. I didn't want to double check it on purpose as I need a working car these days

I was on HWY in traffic and had to slow down then I changed lane and somewhat strongly accelerated so no one hit me in the back and I got flashing MIL light for a while.

I have an automatic transmission and 2.0L gas engine. I feel like the car lowers gear and then has to suddenly change it back or something.

Is something slowly dying in the tranny Did anybody have anything like this? Automatic transmission works smooth if I don't have sudden slow downs and accelerations.

P.S. I just found similar badly named thread with similar problem. Is it possible to merge threads to avoid duplication? Mysterious Event.... completely clueless.

[Smileybug]

Did you scan with VAG-COM?

[mlt]

I didn't have a cable at hand, so I asked mechanics to scan it when I replaced an oil. They said no codes were found. It kind of makes sense since the light is not lit constantly.

[Smileybug]

Was it with VAG-COM though? Generic scanners may not pick up all the codes. If the light is triggered, there is a code. Not all codes trigger a CEL.

[mlt]

This was likely a misfire on 2nd cylinder, since after several such incidents MIL stayed on. It was a time to replace spark plugs and wires.
Be careful changing them it is dangerous to change spark plugs by yourself.!!!!!
Useful info summary spark plug Gap calibration

[NewBeetleMechanic]

Originally Posted by mlt

This was likely a misfire on 2nd cylinder, since after several such incidents MIL stayed on. It was a time to replace spark plugs and wires.
Be careful changing them it is dangerous to change spark plugs by yourself.!!!!!
Useful info summary spark plug Gap calibration

It's not a misfire.


Smileybug asked you the right question. A 1551 or better (scan-tool) will give you the code, I already know what it is going to be.

You will need to buy a new sensor and a tube of RTV. And a heavy magnet, if you dont have one.

(Well maybe two sensors, but one for sure)

Get the actual code and come back.

[mlt]

I just linked orphan thread in case someone will be looking for same symptoms. It happened quite a while ago as you can see from the date.

Originally Posted by NewBeetleMechanic

It's not a misfire.

Smileybug asked you the right question. A 1551 or better (scan-tool) will give you the code, I already know what it is going to be.

You will need to buy a new sensor and a tube of RTV. And a heavy magnet, if you dont have one.

(Well maybe two sensors, but one for sure)

Get the actual code and come back.

There were no codes after flashing was gone. I got it scanned that time at mechanic. Usually I use free VCDS Lite from ROSS-Tech and e-bay cable for $10.

What sensor? and what is RTV? Why magnet?

All I have right now (intermittent random/multiple misfire, MAF problem (I feel like I made a code typo in other thread)) is likely caused by leaking air through injector's air inlet. Before I even changed spark plugs, I was "lucky" to have MIL constantly on for a moment just for mechanic to diagnose misfire in 2nd cylinder. After I left mechanic MIL went off by itself. Though mechanic tried to convince me that clearing the code would be useless as it will come again right away.

[Smileybug]

But you never scanned the car with VAG-COM did you? As I said, generic code readers may not pick up certain codes. A VAG-COM will pick up codes. If the CEL comes on, there is a code stored.

[mlt]

Originally Posted by Smileybug

But you never scanned the car with VAG-COM did you? As I said, generic code readers may not pick up certain codes. A VAG-COM will pick up codes. If the CEL comes on, there is a code stored.

I didn't have the cable that time:-) It is old 2002 beetle, there is no CAN bus, just plain old OBD-II. I usually have no problems using this cable and VCDS Lite. I remember some users here were saying that e-bay cable won't work on Air Bag controller module. But this one did work okay for me.

Anyway, yes, I did not scan with brand name hardware scanner:-)

[mlt]

I'm curious now if I shouldn't have changed spark plugs & wires (and damaging fuel injector:-) ) and the problem was in something else. Spark plugs & wires was my guess, and was confirmed by another mechanic. Along with the fact that those were changed more than 2 years ago, it convinced me to do it.