From Ross-Tech Wiki
17656/P1248/004680 - Start of Injection Timing Regulation: Control Deviation
- 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
- Check/Adjust Injection Start. See TDI Timing Checker
- Check Fuel Supply
- Check/Replace Fuse(s)
- Check/Repair Wiring/Connectors from/to Injection Valve (N108)
- Run Output Tests
- Might by stored with other codes like 17654/P1246/004678.
- When stored in the VW (9M/1J) Golf/Jetta or (1C) Beetle with the ALH engine code Tech Tip 23-02-03 may be helpful. The summary involves removing power at idle to the N108 Cold Start Injection Valve (Fuse 34 on those body styles) while monitoring Basic Setting group 000.2 which is shown under "Timing" when using the TDI Timing Checker. When power is removed from N108 the live reading should change to 255.