OBD II Code

Recently, I was driving my 98 Jetta and the check engine light came on. The car drives normally, no loss of power or anything. So I used an OBDII scanner to read the code and it gave me this reading: "P0605 Internal Control Module Read, Only Memory (ROM) error."

Do you guys know what this could be and what is the fix for this?

Many Thanks!

99% of the time this means the rubber hose that leads into the car's ECU and connects to the internal boost sensor has developed a crack... very commonly inside the ECU itself. Fix is pretty easy... pop the lid off the ECU and replace the hose.

If you search here on that code you should find some good threads with pictures... here's one to get you started:

https://forums.tdiclub.com/showthread.php?t=195336

Ditto what Vince said, that little hose has caused a lot of distress over the years.

This is the condition:



The resolution:



I've done both of mine, 90 B3V AHU conversion and 97 Mk3 TDI. The little hose inside the ECU is not a very good hose TBH, it's protected in there and it still manages to get a hole in it.

Steve

Thank you Vince & Steve! This is very helpful information for me. I'll take a look at the ECU, both inside and the vacuum hose that goes into it.

Porcelain Blue said:

Thank you Vince & Steve! This is very helpful information for me. I'll take a look at the ECU, both inside and the vacuum hose that goes into it.

Click to expand...

Just follow the DIY on myturbodiesel, and be sure to use a new razor blade to carefully cut the hose lengthwise to ease removal. Breaking the plastic nipple on the MAP sensor means you will likely need a new ECU... so be careful!