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Check Lambda probe heating after catalyst > < Checking Lambda probe heating for Lambda probe before catalyst

Golf Mk3

Motronic injection and ignition system from 08.95
Motronic injection and ignition system
Check Lambda probe and Lambda control after catalyst

Special tools, testers and auxiliary items

  • ◆ 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 1598/18
  • ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
  • ◆ Adapter set V.A.G 1594
  • ◆ Current flow diagram

Test conditions

  • ● Coolant temperature at least 80 °C

Functional check

  • ‒ Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address word" 01. When doing this the engine must be running at idling speed.
    (Connecting fault reader and selecting engine electronics control unit .)
 
→ Indicated on display:
Rapid data transfer     HELP
Select function XX
  • ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
 
→ Indicated on display:
Read measured value block     HELP
Input display group number XXX
  • ‒ Press keys 1, 1 and 6 for "Display group number 116" and confirm entry with Q key.
 
→ Indicated on display:
(1...4 = Display zones)
Read measured value block     116     ⇒
     1     2     3     4
  • ‒ Note Lambda probe voltage (display zone 3):

Display zones

1

2

3

4

Display group 116: Lambda probe after catalyst

Display

xxx ms

xxx.x °C

x.xxx V

xxxxxxxx

Indicated

Regulating frequency

Exhaust gas temperature (calculated)

Lambda probe voltage after catalyst

Lambda control status after catalyst

Working range

---

0.0...999.9 °C

0.000...1.000 V

---

Specification

---

min.140.0 °C

0.000...1.000 V
(can fluctuate marginally)

Relevance

---

---

If specification is not attained , continuation

---

Continuation

  • ‒ Carry out test drive to remove possible residue and repeat the check.

If the specification in display zone 3 is not attained even after a test drive:

  • ‒ Check Lambda probe heating
    => Page 24-50 .
  • ‒ Rev-up to above 3000 rpm.

If the figure in display zone 3 remains constant => Page 24-46 , evaluating display group 116.

Evaluating display group 116

Display group: 116

Display zone: 3

Possible fault cause

Fault elimination

Approx. 0.435 V

Wiring open circuit in wire 4 between Lambda probe and control unit

- Check basic voltage=> Page 24-47

Approx. 0.440 V

Wiring open circuit in wire 3 between Lambda probe and control unit

Approx. 1.085 V

Short to positive in wire 4 between Lambda probe and control unit

- Check Lambda probe wiring
=> Page 24-48

Approx. 0.000 V

Short to earth in wire 4 between Lambda probe and control unit

Relevance of figures in 8 digit number block

Relevance if display = 1

x

x

x

x

x

x

x

x

Lambda control status (display group 116)

1

Fault in fault memory

1

Fault detected during this diagnosis

1

Diagnosis complete during this drive

1

Diagnosis currently active

1

Lambda control before catalyst active

1

Lambda probe after catalyst ready

1

Both Lambda probes cold

1

Probe heating after catalyst on

Checking basic voltage
 
N24-0277
  • ‒ → Separate 4 pin connector (brown) to Lambda probe after catalyst (G108) -2-.
 
N24-0284
  • ‒ → Connect multimeter using aux. cables from V.A.G 1594 to measure voltage at contacts 3+4 (connector to Motronic control unit).
  • ‒ Start engine and measure basic voltage.
         Specification: 0.40...0.50 V
  • ‒ Switch off ignition.

If the specification is not obtained:

  • ‒ Check Lambda probe wiring
    => Page 24-48

If the specification is attained:

  • ‒ Replace Lambda probe after catalyst (G108).

Checking Lambda probe wiring
 
N24-0178
  • ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom -arrow-.
 
N24-0277
  • ‒ → Separate 4 pin connector (brown) to Lambda probe after catalyst (G108) -2-.
 
N24-0285
  • ‒ → Check wiring between test box and 4 pin connector to Motronic control unit for open circuit according to current flow diagram.
         Contact 3+socket 58
         Contact 4+socket 13
         Wire resistance: Max. 1.5 ω
  • ‒ Additionally check the wiring to 4 pin connector for short to one another.
         Contact 4+socket 58
         Specification: ∞ω
  • ‒ Check screening for short to probe wiring.
         Contact 4+socket 56
         Contact 3+socket 56
         Specification: ∞ω

If no wiring fault is detected:

  • ‒ Replace Motronic control unit (J220).
  • ‒ Read-out the readiness code=> Page 01-35 .

Check Lambda probe heating after catalyst > < Checking Lambda probe heating for Lambda probe before catalyst