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· Registered
3 Posts
Discussion Starter · #1 ·
HELP!... 2002 JETTA TDI, about 143,000 miles. Bought it 6 months ago, runs great! Had timing belt and fuel filter replaced at that time. Occasional 17656 code initially, but nothing lately until a week ago on a long trip. I clear it, but it comes back after a couple trips. Even when the engine light is on, it still runs great, plenty of power, starts instantly, idles smoothly. Getting upper-40's fuel milage. Hard to believe there's anything really wrong, but what should I be looking at to get rid of the intermittant code?...

I've read thru some of the posts and it seems to be a code that is caused by problems with the injection pump, but most posts mention the engine running badly, so not sure that's the cause of my code!

· Premium Member
23,904 Posts
Try this:
Possible Solutions

  • Check/Adjust Injection Start
  • Check Fuel Supply
  • Check/Replace Fuse(s)
  • Check/Repair Wiring/Connectors from/to Injection Valve (N108)
or this: http://www.myturbodiesel.com/forum/f9/free-eobd-ii-error-codes-software-2919/

Basically, it could be a wire shorting out quickly and throwing the code. Probably not a fuse since it's not constant. It's possible there is a fuel blockage in the fuel filter, (should be changed every 20,000 miles) or fuel tank, or that injection timing is off. Check the injection pump timing. There is a procedure on how to do this in the mk4 ALH engine timing belt article.

· Premium Member
9,237 Posts
VAG Error Code: 17656

EOBD II Error Code: P1248

Fault Location:Start of injection - control difference

Possible Cause:
Loss of Power at high Engine Speeds.
Engine difficult to Start.

Start of Injection Timing Regulation not OK.
Injection Pump Control Range blocked/dirty (e.g. by Metal Particles).
Engine has stalled / ran out of Fuel recently.
Wiring/Connectors from/to Injection Valve (N108) faulty.
Injector needle lift sensor.
Fuel level low.
Pump timing.

Possible Solutions:
Check/Adjust Injection Start.
Check Fuel Supply.
Check/Replace Fuse(s).
Check/Repair Wiring/Connectors from/to Injection Valve (N108).

Special Notes:
Might by stored with other codes like 17654/P1246/004678.

Cheers chitty. ;)

· Registered
2 Posts

Did you ever solve this issue? I am having the same problem. The code shows, I can clear it, but it pops back up again. The IP was replaced, but I have adjusted the timing folowing procedure, and it runs perfect right now. I put a new fuel filter in at the same time as the pump replacement. Anyone have thoughts on this?

If it was a fuse, which would I be checking??

Should I just clean the wiring connector with electronic cleaner??

Any help would be great...thank you!

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