Volkswagen 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

• ● Coolant temperature must be at least 80 °C, =>display group 04, display zone 3.
• ● Exhaust system between catalyst and cylinder head must be free of leaks

Functional check

• ‒ 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, 3 and 0 for the "Display group number 30" and confirm entry with Q key.

• ‒ Check Lambda regulation status before catalyst (display zone 2):
       Specification: 1 1 0
  

Note:

The 3rd bit in display zone 2 will not be set to 1 until partial throttle (2500-4000 rpm) is reached.

Significance of 3 digit number block in display zone 1:

If the specification is not obtained:

• ‒ Check Lambda probe heating after catalyst
  => Page 24-33 .

If the specification is obtained:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 4 for the function "Initiating basic settings" and confirm entry with Q key.

• ‒ Press keys 0, 3 and 6 for "Display group number 36" and confirm entry with Q key.

• ‒ Apply brake and hold down brake pedal. The engine speed will be raised automatically. After a moment, the following appears in display zone 2:
       B1-P2 OK

If "B1-P2 n.OK"
     appears in display zone 2,

• ‒ Check Lambda probe 2 voltage at idling speed in display zone 1.
       Specification: 0.000...1.000 V
• ‒ Continue check according to following table.

If the Lambda regulation in display zone 1 does not fluctuate as stated:

• ‒ Press ⇒key.
• ‒ Press keys 0 and 6 for the "End data transfer" function and confirm input with the Q key.
• ‒ Carry out road test and burn Lambda probes clean and repeat check.

Observe the valid safety precautions when carrying out a road test => Page 24-29 .

If the the specifications in display zone 1 are not obtained even after a test drive, or the value does not fluctuate by at least 2 %:

• ‒ Renew the Lambda probe after catalyst (G130).

Checking basic voltage

• ‒ → Separate 4-pin connector to Lambda probe (G130) -arrow-.

• ‒ → Connect multimeter with aux. cables from V.A.G 1594 to measure voltage at contacts 3+4 (connector to engine control unit).
• ‒ Switch on ignition and measure basic voltage.
       Specification: 0.40...0.50 V
• ‒ Switch off ignition.

If the specification is obtained:

• ‒ Renew the Lambda probe after catalyst (G130).

Checking Lambda probe wiring, Lambda probe 2

• ‒ → Separate 4-pin connector to Lambda probe (G130) -arrow-.

• ‒ → Check wiring for open circuit between test box and 4-pin connector (to control unit) using current flow diagram.
       Contact 3+socket 68
       Contact 4+socket 69
       Wire resistance: Max. 1.5 ω
• ‒ Check the wiring at connector contacts 3+4 for short circuit to contacts 1+2.

If no fault is detected in the wiring:

• ‒ Renew the Lambda probe after catalyst (G130).