Audi Workshop Service and Repair Manuals

• ‒ → Remove oil dipstick -1- from guide tube.
• ‒ Remove engine cover -arrows-.
• ‒ Reinsert dipstick in guide tube.

Checking internal resistance

• ‒ Switch ignition off.
• ‒ → Unplug connector from boost pressure control solenoid valve -N75 -Item 3-.

• ‒ → Connect multimeter between contacts 1 and 2 to measure resistance.
• ‒ Specified value: 14...20 ω

If specified value is not attained:

• ‒ Replace solenoid valve for boost pressure control -N75.

Checking power supply

• ‒ → Connect multimeter between contact 2 and earth to measure voltage.
• ‒ Switch the ignition on.
• ‒ Specified value: approx. battery voltage

If specified value is not attained:

• ‒ Check wiring for open circuit and service if necessary.

Checking actuation

• ‒ → Connect voltage tester V.A.G 1527 B between contacts 1 and 2.
• ‒ Start final control diagnosis and activate solenoid valve for boost pressure control -N75:

=> TDIInjection and Glow Plug System(4-cyl Pump Jet); Repair group 01; Final control diagnosis

• ‒ The LED must flash slowly.

Note:

Voltage testers with a low current consumption continue to glow faintly between actuation from the engine control unit (rather than extinguishing completely) and become much brighter when actuated.

If the LED lamp does not react as described:

• ‒ Switch ignition off.
• ‒ → Connect the V.A.G 1598/31 test box to wiring harness connectors; the engine control unit should not be connected. Attach the earth clip of test box to earth -arrow-.

=> TDIInjection and Glow Plug System(4-cyl Pump Jet); Repair group 23

• ‒ → Check for open circuit and short to positive or earth in the following wiring connections:

• ‒ Rectify any open/short circuit as necessary.