SEAT Workshop Service and Repair Manuals

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ Test box V.A.G 1598/31
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● → Fuse No. 14 must be OK.
• ● The battery voltage must be at least 11.5 V.
• ● Fuel pump relay must be OK

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit .)

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press keys 0, 4 and 1 for "Display group number 41" and confirm entry with Q key.

• ‒ Run engine for 2 minutes at idling speed.
• ‒ Check Lambda probe heater status in display zone 2:
      Display: Htg.bC.ON, Htg.bC.OFF (alternating)

Note:

The Lambda probe heating may be switched on or off depending on the operating mode of the engine, therefore the display in display zone 2 may show "Htg.bC.ON or alternating from Htg.bC.ON to Htg.bC.OFF.

If the display does not indicate as described:

• ‒ Press ⇒key.

• ‒ Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
• ‒ Switch off ignition.
• ‒ → Separate 6-pin connector -1- to Lambda probe before catalyst (G39).

• ‒ → Set multimeter to measure resistance and connect it to contacts 3 + 4 of connector to Lambda probe. Check probe heating for closed circuit.
      Specification: 2.5...10 ω(at room temperature)

If it is determined that probe heating has an open circuit:

• ‒ Replace the Lambda probe before catalyst (G39).
• ‒ Erase fault memory to put learnt values in a neutral setting => Page 01-18, Interrogating and erasing learnt values.

If probe heating has continuity:

• ‒ → Set multimeter to measure voltage and connect to contact 3 (connector to engine control unit) and earth.
• ‒ Start engine and run at idling speed.
• ‒ Measure voltage supply:
      Specification: 11.0...14.5 V

If the specification is not obtained:

• ‒ Check wiring from contact 3 to fuel pump relay (J17) using current flow diagram.

=> Current flow diagrams, Electrical fault finding and Fitting locations binder

If the specification is obtained:

• ‒ → Connect multimeter to contacts 3 and 4 (connector to engine control unit).
• ‒ Check activation by engine control unit while observing display group 41, display zone 2.
  Display Htg.bC.ON
      Specification: 11.5...14.5 V
  Display Htg.bC.ON/Htg.bC.OFF (alternating)
      Specification: between 0.0...12.0 V fluctuating
• ‒ Switch off ignition.

If the specification is not obtained:

• ‒ Remove battery.

• ‒ → Connect test box V.A.G 1598/31 to control unit wiring harness. The engine control unit remains disconnected.

• ‒ → Check wiring for open circuit between test box and 6-pin connector using current flow diagram.
      Contact 4+socket 5
      Wire resistance: max. 1.5 ω

If no wiring fault is detected:

• ‒ Renew engine control unit => Page 24-109.