With Manufacturer's Scan Tool

Glow plug system, checking

Vehicles from model year 2002 >

NOTE: Vehicles from model year 2002 have a glow period control unit (J370) installed. It is not possible to optically and acoustically check the activation, this is only possible by connecting a current pick-up clamp to the glow plug wiring.

Special tools and equipment





- VAG 1715 Multimeter

Test prerequisites:





- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- Diesel Direct Fuel Injection (DFI) Engine Control Module -J248- OK.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with A/C, it must be switched off.
- Alternator OK, checking:
- Engine must be cold.

Test sequence

NOTE: The test must be done within 3 minutes after starting the engine.

- Start the engine and run at idling speed.
- Connect VAG 1715 Multimeter in sequence to glow plug wiring using a current pick-up clamp.
- Specified value in VAG 1715 Multimeter display of at least 6 A (amps).
- If the specification is not obtained:
- Check DTC memory, and erase DTC memory after correcting malfunctions. [1][2]Reading Diagnostic Trouble Codes
- Read-out the readiness code. If the DTC memory has been erased or the Engine Control Module was disconnected from battery positive, the readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes