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Testing lambda probe signal wiring and activation > < Checking function

A4 Mk1

Motronic Fuel Injection and ignition system (4-cyl.) 07.96ä
Checking lambda control
Checking lambda probe heating
  • ‒ Read measured value block, Display Group 25, engine at idling speed .
 
→ Indicated on display:
Read measurement block 25    ⇒
    Idling speed     0.35 crankshaft 87.2 5C    8.7 Ohm
  • ‒ Check display in display zone 4.
  • Specification: 6...15 Ohm

If the specification is not obtained:

  • ‒ Switch off ignition.
  • ‒ Disconnect the connector to the lambda probe => Installation locations - Overview - Page 24-4.
 
A24-0013
  • ‒ → Connect the multimeter (voltage measurement range) to contact 1 on the connector and to earth.
  • ‒ Operate the starter briefly (the engine may start briefly).
  • Specification: approx. battery voltage

If the specification is not obtained:

  • ‒ Check the wiring.

=> "Current Flow Diagrams, Electrical Fault Finding and Fitting Locations" binder

If the specification is obtained:

  • ‒ Connect test box V.A.G 1598/22 to wiring harness for engine control unit
    .
 
A24-0013

The following wiring connections should be checked for open circuits and/or short to positive or negative.

4-pin connector on the wiring harness, contact.

Test box V.A.G 1598/22, socket

2

27
  • ‒ Rectify any open/short circuit as necessary.

Testing lambda probe signal wiring and activation > < Checking function