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 1598/22
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram
• ◆ Chilling spray (commercially available)

Note:

If sender or connecting wiring is defective the control unit operates with a substitute temperature of 19.5 °C.

Test sequence

• ‒ Connect the fault reader V.A.G 1551 (V.A.G 1552). Then switch ignition on and select engine control unit with the "Address word" 01.
  (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, 0 and 3 for "Display group number 3" and confirm entry with Q key.

• ‒ Read off intake air temperature value in display zone 4.

    1)    If a temperature is displayed which is below the ambient air temperature of the sender, check sender wiring for transfer resistances. Note when doing this that sender is heated from external sources, e.g. radiated heat when engine is not running.

Continuation of check when display reads approx. -46 °C:

• ‒ → Pull connector -1- off intake air temperature sender (G42) -2-.
• ‒ Bridge connector contacts using aux. cables from V.A.G 1594 and observe display.

If display jumps to approx. 141 °C:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Renew intake air temperature sender (G42).

If display remains at approx. -46 °C:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ → Connect test box V.A.G 1598/22 to control unit wiring harness.

• ‒ → Check wiring between test box and 2 pin connector -1- for open circuit using current flow diagram.
      Contact 1+socket 54
      Contact 2+socket 67
      Wire resistance: max. 1.5 ω
• ‒ Check wiring additionally for short circuit to battery positive.
      Specification: ∞ω

If no fault in wire is detected:

• ‒ Renew engine electronics control unit => Page 24-105.

Continuation of check when display reads approx. 141 °C:

• ‒ → Pull connector -1- off intake air temperature sender (G42) -2-.

If display jumps to approx. -46 °C:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
• ‒ Switch off ignition.
• ‒ Renew intake air temperature sender (G42).

If display remains at approx. 141 °C:

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

• ‒ → Check wiring to control unit connector at 2 pin connector contact 2 for short to wire contact 1 as well as to vehicle earth.
      Specification: ∞ω

If no wiring fault is detected:

• ‒ Renew engine electronics control unit => Page 24-105.

Continuation of check when display = ambient temperature:

• ‒ → Remove the intake air temperature sender. Attach connector again.
• ‒ Note intake air temperature value in display zone 4.
• ‒ Spray sender with commercial chilling agent whilst observing the temperature value. The temperature value must
      decrease.
• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.