SEAT Workshop Service and Repair Manuals

Notes:

• ◆ Raise vehicle to reach Lambda probe connector.
• ◆ Only gold-plated contacts may be used to service contacts in Lambda probe connector.

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

• ● → All fuses 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.

• ‒ Check the specifications for the Lambda probe heating in display zone 2.

Note:

The Lambda probe heating may be switched ON or OFF depending on the operating conditions of the engine, therefore the display in display zone 2 may show "Htg.b(a)C.ON" or alternating from "Htg.b(a)C.ON" to Htg.(b)aC.OFF".

If the specification is obtained:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.

If the specifications are not obtained:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ → Separate 6-pin connector (black) to Lambda probe before catalyst (G39) -arrow-.

• ‒ → Check probe heating for continuity at Lambda probe connector contacts 3 + 4.

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

• ‒ Replace the Lambda probe before catalyst (G39).

Note:

If the Lambda probe is renewed, the learnt values in the engine control unit must be erased => Page 24-148

• ‒ Interrogate fault memory, if necessary, repair any faults and then erase fault memory => Page 01-16, interrogating and erasing fault memory.
• ‒ Read-out the readiness code=> Page 01-64.

If probe heating has continuity:

Checking voltage supply

• ‒ → Connect multimeter using aux. cables from V.A.G 1594 to measure voltage at contacts 3 and 4 (connector to engine control unit).
• ‒ Start engine and run at idling speed.
• ‒ Measure voltage supply while observing display group 41, display zone 2.
  Display, Htg.bC.ON:
      Specification: 11.0...14.5 V
  Display, Htg. bC.ON/Htg.bC.OFF (alternating):
      Specification: Between 0.0...12.0 V fluctuating
• ‒ Switch off ignition.

If no voltage is present:

• ‒ 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 according to current flow diagram.
      Contact 4+socket 5
      Wire resistance: Max. 1.5 ω

If the specification is obtained:

• ‒ Check wire for open circuit between 6-pin connector contact 3 and fuel pump relay (J17) using current flow diagram.
      Wire resistance: max. 1.5 ω