Volkswagen 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

Check conditions

• ● Coolant temperature at least 85 °C
• ● Exhaust system between catalyst and cylinder head free of leaks

Functional check of Lambda probe

• ‒ 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, ABU

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

• ‒ Note reading in display zone 5 (Lambda probe reading). The displayed figure must fluctuate
       at least 30 times per minute
  in range
       between 106...150.

Engine codes AEA

• ‒ Input 07 for "Display group number" and confirm with Q.

• ‒ Note Lambda probe voltage in display zone 2. The voltage must
       fluctuate at least 30 times per minute
  in range of
       0... 1.0 V.

If the displayed figure/probe voltage does not fluctuate as stated:

• ‒ Check Lambda probe heating => Page 24-41 .
• ‒ Check Lambda probe for soot. Renew if necessary.

Checking Lambda probe working range

Engine code ABD, ABU

• ‒ Note reading in display zone 6 (altitude correction).

If specification attained:

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

If specification not attained or exceeded:

• ‒ Check Lambda probe heating => Page 24-41 .
• ‒ Check intake air system for leaks (unmetered air). To do this, leave fault reader in this setting and allow engine to continue running
  => Page 24-96
• ‒ Check Lambda probe for soot. Renew if necessary.

Engine code AEA

• ‒ Press C key.

• ‒ Input 05 for "Display group number" and confirm with Q.

• ‒ Note displayed figure in display zone 3.
       Specification: 0.99...1.01
• ‒ Note displayed figure in display zone 4 (altitude correction).

If specification attained:

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

If specification not attained or exceeded:

• ‒ Check Lambda probe heating => Page 24-41 .

• ‒ Check intake air system for leaks (unmetered air). To do this, leave fault reader in this setting and allow engine to continue running
  => Page 24-96
• ‒ Check Lambda probe for soot. Renew if necessary.

Checking Lambda probe wiring

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.

• ‒ → Separate 4 pin connector to Lambda probe -1-.
• ‒ Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
       Contact 3+socket 15
       Contact 4+socket 38
       Wire resistance: Max. 1.5 ω
• ‒ Check wiring at 4 pin connector for short to one another.
       Specification: ∞ω

If the specifications are not attained:

• ‒ Check wiring according to current flow diagram.