Volkswagen Golf Workshop Service and Repair Manuals

Special tools, testers and auxiliary items

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with
       ▸ 07.93: Cable V.A.G 1551/1
       08.93 ▸: Cable V.A.G 1551/3
• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit (address word 01); carry out selection at idling.
  

• ‒ Input 08 for "Read measured value block" function and confirm with Q.

Engine code ABD ▸ 01.93:

• ‒ Input 00 for "Display group number" and confirm with Q.

Engine code ABD 02.93 ▸ ABU, AEA:

• ‒ Input 01 for "Display group number" and confirm with Q.
• ‒ Note intake air temperature figure in display zone 2.
• ‒ Determine possible cause of fault according to the table and continue with appropriate check.

     1)     If a temperature is displayed which deviates greatly from the ambient temperature of the sender, check sender wiring for transfer resistances. For display group 0:
          125 corresponds to approx. 20 °C
          25 corresponds to approx. 85 °C

     2)     Check is only possible when the engine is cold.

Continuation of check when display = approx. 240 or approx. -50°C:

• ‒ → Pull 4 pin connector -1- of coolant temperature sender (G62) -2-.
• ‒ Bridge connector contacts 1+3 with aux. cables from V.A.G 1594 and observe display.

Display 0 or approx. 130 ° C:

• ‒ Replace coolant temperature sender -2-.

Display approx. 240 or approx. -50 ° C:

• ‒ Press ⇒ button.
• ‒ Input 06 for "End output" and confirm with Q.
• ‒ Switch off ignition

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Check wire between test box socket 42+4 pin connector contact 3 for open circuit according to current flow diagram.
       Wire resistance: Max. 1.5 ω
• ‒ Additionally check wire for short to battery positive.
       Specification: ∞ω
• ‒ Check wire between test box socket 17+4 pin connector contact 1 for open circuit according to current flow diagram.
       Wire resistance: Max. 1.5 ω

If no fault in wire is detected:

• ‒ Renew Mono Motronic control unit (J257)
  , item 2 .

Continuation of check when display = 0 or approx.130 °C:

• ‒ → Pull 4 pin connector -1- of coolant temperature sender (G62) -2-.

Display approx. 240 or approx. -50 ° C:

• ‒ Replace coolant temperature sender -2-.

Display 0 or approx. 130 ° C:

• ‒ Press ⇒ button.
• ‒ Input 06 for "End output" and confirm with Q.
• ‒ Switch off ignition
• ‒ Pull connector off Mono Motronic control unit.
• ‒ Check wire between control unit connector and 4 pin connector contact 3 for short to wire contact 1 and to vehicle earth, according to current flow diagram.
       Specification: ∞ω

If no fault in wire is detected:

• ‒ Renew Mono Motronic control unit (J257)
  , item 2 .

Continuation of check when display = coolant temperature:

Functional check of sender

Display group 00:

Display group 01:

Notes:

• ◆ If the display on fault reader jumps by 2...5 °C, it is a control unit fault and not caused by a defective sender.
• ◆ If irregular engine running occurs in certain temperature ranges and the temperature figure does not increase without interruption, the temperature signal is temporarily interrupted and the sender must be renewed.

• ‒ Press ⇒ key.
• ‒ In put 06 for "End output" and confirm with Q.