volkswagen Workshop Repair Guides

Volkswagen Workshop Service and Repair Manuals

Evaluating measured value blocks, display groups 50...69 -Speed regulation- > < Evaluating measured value blocks, display groups 10...29 -Ignition-
Simos injection and ignition system
Evaluating measured value blocks, display groups 30...49, 99 -Lambda regulation-
Evaluating measured value blocks, display groups 30...49, 99 -Lambda regulation-

Display group 30 -Lambda regulation-

▪ Engine running at idling speed

Read measured value block 30

◂ Indicated on display

xxx

xxx

1

2

3

4

◂ Display zones

Specification

Evaluation

Lambda regulation status after catalyst

110

Lambda regulation status before catalyst

111

=> Page 01-137

Notes on display zones 1 and 2:

  • ◆ The Lambda probe heating may be switched on or off depending on the operating condition of the engine, i.e. the 1st position in display zones 1 or 2 may show 1 or 0.

    The 3rd position in display zone 2 is not set to 1 until in part throttle range.

Significance of figures in 3-digit number block, display zones 1 and 2 - status of Lambda regulation before and after catalyst

Significance if display = 1

1

2

3

1

Lambda regulation active

1

Lambda probe operationally ready

1

Lambda probe heating on

Display group 31 -Lambda regulation- constantly operating Lambda probes

▪ Engine running at idling speed

Read measured value block 31

◂ Indicated on display

x.xxxx

x.xxxx

1

2

3

4

◂ Display zones

Specification

Evaluation

Lambda specification, Bank 1

0.9900...1.0100

---

Lambda actual value, Bank 1

0.9900...1.0100

---

Display group 32 -Lambda regulation- Lambda learnt values

▪ Engine running at idling speed

Read measured value block 32

◂ Indicated on display

xx.x %

xx.x %

1

2

3

4

◂ Display zones

Specification

Evaluation

Lambda learnt value at part load (multiplicative)

-10...10 %

=> Page 01-140

Lambda learnt value at idling speed (additive)

-14...14 %

=> Page 01-140

Notes on display zones 1 and 2:

    Low values indicate that the engine is running too rich and therefore the Lambda regulation is leaning the mixture.

  • ◆ High values indicate that the engine is running too lean and therefore the Lambda regulation enriches the mixture.
  • ◆ add = additive - The effects of the fault (e.g. unmetered air) will reduce as the engine speed increases. The injection period will be modified by a fixed amount for additive learnt values. This amount is not dependent upon the basic injection period.
  • ◆ mul = multiplicative - The effects of the fault (e.g. faulty injector) will increase as the engine speed increases. A multiplicative learnt value is a proportional change to the injection period. This change is dependent on the basic injection period.

Evaluating display zone 32, display zones 1 and 2 - Lambda learnt values

Appears on display

Possible fault cause

Fault elimination

Low Lambda learnt values

- Low learnt values at idling but with normal learnt values at part throttle: possible oil dilution (high level of fuel in oil)

- Disappears after motorway drive or oil change

- Injector leaking

- Check injector

- Fuel pressure too high

- Check fuel pressure regulator and holding pressure => Page 24-72

- Activated charcoal filter solenoid valve 1 permanently open

- Check activated charcoal filter solenoid valve 1 => Page 01-61 , Final control diagnosis

- Air mass meter defective

- Check air mass meter => Page 24-39

- Lambda probe heating defective or Lambda probe (G39) soiled

- Check Lambda probe heating before catalyst

- Check Lambda probe and Lambda regulation before catalyst => Page 24-82

Continued =>next page

Appears on display

Possible fault cause

Fault elimination

High Lambda learnt values

- High learnt values at idling speed, not so high learnt values at part throttle: possible unmetered air in area of intake manifold

- Check intake air system for leaks

- Unmetered air between air mass meter and throttle valve

- Rectify cause

- Injector blocked

- Check quantity injected rate

- Display zones 1 and 2 high: air mass meter defective

- Check air mass meter => Page 24-39

- Fuel pressure too low

- Check fuel pressure regulator and holding pressure => Page 24-72

- Unmetered air at exhaust manifold gasket

- Lambda probe heating defective or Lambda probe soiled

- Check Lambda probe heating

Display group 33 -Lambda regulation- Lambda regulation values

▪ Engine running at idling speed

Read measured value block 33

◂ Indicated on display

xx.x %

x.xxx V

1

2

3

4

◂ Display zones

Specification

Evaluation

Lambda probe voltage, Lambda probe before catalyst

1.4...1.6 V

---

Lambda regulator before catalyst

-10.0...10.0 %

=> Page 01-143

Notes on display zone 1:

  • ◆ The display must fluctuate around 0. If constant 0 is displayed, the Lambda regulation has switched from regulation to control, because there is a fault in the Lambda regulation. Interrogate fault memory => Page 01-21 .

Notes on display zone 2:

  • ◆ The voltage signal "rich mixture (low level of residual oxygen)" is below 1.5 V.
  • ◆ The voltage signal "lean mixture (high level of residual oxygen)" is above 1.5 V.

Evaluating display group 33, display zone 1 - Lambda regulator before catalyst

Appears on display

Possible fault cause

Fault elimination

Outside tolerance range

- Minus range: Mixture too rich, Lambda control weakens mixture
- Positive range: Mixture too lean, Lambda control enriches mixture

- Wait 30 seconds until the display has stabilised

- Unmetered air

- Check intake system for leaks
=> Page 24-76

- Injector defective

- Check injection rate => Page 24-65

- Lambda learnt value on limit

- Check Lambda learnt value in display group 32

Display group 34 -Lambda regulation- Lambda probe diagnosis before catalyst (checking ageing)

▪ Vehicle stationary, engine running at 2500...4000 rpm

▪ Control unit in mode 04-Basic setting

Read measured value block 34

◂ Indicated on display

xxxx rpm

xxx.x °C

x.xx s

Text

1

2

3

4

◂ Display zones

Specification

Evaluation

Result of Lambda probe before catalyst age check (test OFF/test ON/B1-P1 OK / B1-P1 n.OK)


B1-P1 OK


---

Dynamic factor

---

---

Catalyst temperature

min. 400 °C

---

Engine speed

2500...4000 rpm

---

Note on display zone 2:

Value calculated from engine speed and engine load.

Note on display zone 3 and 4:

The dynamic factor is a Lambda probe ageing measurement. The control unit compares the adjustment frequency of the Lambda probes evaluation circuitry with a specification stored in the control unit. If the value is not reached, the message: "B1-P1 n.OK" is indicated in display zone 4.

Display group 41 -Lambda regulation- Lambda probe heating

▪ Engine running at idling speed

Read measured value block 41

◂ Indicated on display

xxxx ω

Text

xxxx ω

Text

1

2

3

4

◂ Display zones

Specification

Evaluation

Lambda probe heating after catalyst

Htg.aC.ON

---

Internal resistance of Lambda probe after catalyst

up to 1000 ω

---

Lambda probe heating before catalyst

Htg.bC.ON

---

Internal resistance of Lambda probe before catalyst

---

---

Note on display zone 3:

This value is temperature dependent. Specification for "Engine at operating temperature".

Display group 43 -Lambda regulation- Lambda probe after catalyst diagnosis

▪ Control unit in mode 04-Basic setting

- Depress brake pedal

▪ Vehicle stationary, engine runs at increased idling speed

Read measured value block 43

◂ Indicated on display

xxxx rpm

xxxx °C

x.xx

Text

1

2

3

4

◂ Display zones

Specification

Evaluation

Result of adaption diagnosis (test OFF/test ON/syst. OK/syst. n.OK)


Syst. OK


---

Lambda probe voltage, Lambda probe after catalyst

0...1 V

---

Catalyst temperature

APF: at least 100 °C
AVU: at least 200 °C

---

Engine speed

approx. 1400 rpm

---

Note on display group 60:

The Lambda regulation after catalyst is the primary system and is used to guide the Lambda regulation before catalyst. It corrects light rich and lean displacements of the Lambda probe before catalyst by means of map-dependent correction displacements (max. + / - 2.5 %).

Evaluating display group 43, display zone 3 - Lambda probe voltage, Lambda probe after catalyst

Appears on display

Possible fault cause

Fault elimination

Constant 1.100 V

- Short to positive via:
- Lambda probe, probe wiring, earth wiring, engine control unit

- Check Lambda probe wiring
=> Page 24-98

Constant between
0.390...0.500 V

- Open circuit via:
- Lambda probe, probe wiring, earth wiring, engine control unit

Constant 0.000 V

- Short to earth via:
- Lambda probe, probe wiring, earth wiring, engine control unit

Display group 46 -Lambda regulation- Catalyst diagnosis (conversion test)

▪ Control unit in mode 04-Basic setting

▪ Vehicle stationary, engine runs at increased idling speed

Read measured value block 46

◂ Indicated on display

xxxx rpm

xxxx °C

xx

Text

1

2

3

4

◂ Display zones

Specification

Evaluation

Result of catalyst conversion test (Test OFF/test ON/Cat B1 OK/Cat B1 n.OK)


Cat B1 OK


---

Measurement value of catalyst conversion

---

---

Catalyst temperature

min. 400 °C

---

Engine speed

2500...4500 rpm

---

Engine code AVU

Display group 99 -Lambda regulation- Lambda regulation operating condition

▪ Engine running at idling speed

▪ Control unit in mode 04-Basic setting, Lambda regulation off

▪ Control unit in mode 08-Read measured value block, Lambda regulation on

Read measured value block 99

◂ Indicated on display

xxxx rpm

xx.x °C

x.x %

Text

1

2

3

4

◂ Display zones

Specification

Evaluation

Lambda regulation operating mode

λ-Reg. OFF or
λ-Reg. ON

---

Lambda regulator before catalyst

-10.0...10.0 %

=> Page 01-143

Coolant temperature

80...115 °C

=> Page 01-119

Engine speed (idling speed)

640...900 rpm

=> Page 01-113

Notes on display zone 4:

  • ◆ For a defined fault finding the Lambda regulation is switched off when selecting display group 99 under "Basic setting" or switched on under "Read measured value block".
    When the function 04 "Basic setting" is exited the Lambda regulation is automatically active again.
  • ◆ It is possible to switch between the function 04 "Basic setting" and the function 08 "Read measured value block" by pressing the keys 4 and 8 on V.A.G 1551/1552.

Evaluating measured value blocks, display groups 50...69 -Speed regulation- > < Evaluating measured value blocks, display groups 10...29 -Ignition-