Measured Value Blocks (detailed)
 


Display group 1 -Basic functions

Read measured value block 1

?

[ltrif ] Indicated on display

 

 

 

 

xxxx rpm

xxx C

x.xxx V

xxxxxxxx

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Adjustment conditions

00000000

 
 

 

 

 

 

 

Lambda probe voltage

0.000...1.000 V

 
 

 

 

 

Coolant temperature

85...110 C

 
 

 

Engine speed (idling speed)
Engine code AFK
Engine code AHW with manual gearbox
Engine code AHW with automatic gearbox


790...890 rpm1)
800...900 rpm1)
630...730 rpm1)

 

Note on display zone 1:

The idling speed will be increased by the control unit under the following conditions:

  • When the battery voltage is too low: up by approx. 150 rpm.
  • After a long full throttle drive and high temperatures: up by approx. 125 rpm.
  • After starting the engine when intake air temperature is above 75 C or coolant temperature is above 105 C: up by approx.       70 rpm.
  • The idling speed is raised to 750 rpm at selected driving range.
  • With air conditioner switched on, the idling speed is raised to 890 rpm (engine code AFK) or 800 rpm (engine code AHW).

Note on display zone 2:

As soon as a fault is stored in the fault memory which affects the intake air temperature sender (G42), the engine control unit will use a replacement value of 80 C for the temperature value.

Notes on display zone 3:

  • The voltage signal "rich mixture (low level of residual oxygen)" is approx. 0.700...1.000 V.
  • The voltage signal "lean mixture (high level of residual oxygen)" is approx. 0.000...0.300 V.
  • When changing from "rich" to "lean" and back again the voltage jump will change from 0.700...1.000 V to 0.000...0.300 V or    back again.
  • Due to the steep voltage jumps the Lambda control cannot keep the ideal mixture composition  = 1.0 constant. The control fluctuates constantly between conditions "slightly too lean" and "slightly too rich".
  • The displayed value must temporarily drop below 0.300 V and exceed 0.600 V. Displayed values below 0.450 V signifies lean, above 0.450 V rich.

Evaluating display group 1, display zone 1 - Engine speed (idling speed)

Appears on display

Possible fault cause

Fault elimination

Lower than
specification

- Throttle valve control part sticking or defective

- Check throttle valve control part
 

Higher than
specification

- Idling switch not closed/defective

- Interrogate fault memory,

 

 

- Large amount of unmetered air (cannot be compensated for by the idling stabilisation)

- Check intake air system for leaks
 

 

 

- Throttle valve control part sticking/defective

- Check throttle valve control part
 

Evaluating display group 1, display zone 2 - Coolant temperature

Appears on display

Possible fault cause

Fault elimination

Less than 80 C

- Engine too cold

- If necessary carry out test drive

 

 

- Coolant temperature sender or wiring to engine control unit

- Check coolant temperature sender
 

More than 110 C

- Radiator soiled

- Clean radiator

 

 

- Radiator fan not functioning

- Check function

 

 

- Thermostat defective

 
 

 

- Coolant temperature sender or wiring to engine control unit

- Check coolant temperature sender
 

 
 

Evaluating display group 1, display zone 3 - Lambda probe voltage

Appears on display

Possible fault cause

Fault elimination

Display does not fluctuate

- Large amount of unmetered air

- Check air intake system for leaks
 

(Constant 0.000... 0.300 V
or

- Spark plug defective

- Check spark plugs

Constant 0.700...1.000 V)
 

- Fuel pressure too low or too high

- Check fuel pressure regulator and holding pressure

Appears on display

Possible fault cause

Fault elimination

 

- Injector defective

- Check injectors

 

 

- Coolant temperature sender defective

- Check coolant temperature sender
 

 

 

- Activated charcoal filter solenoid valve 1

- Check solenoid valve 1
 

 

 

- Lambda probe heating not functioning

- Check Lambda probe heating
 

 

 

- Lambda probe(s) defective or soiled

- Check Lambda probe and Lambda control

Constant 1.200 V

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

- Check Lambda probe wiring
 

Constant between
0.040...0.050 V

- Open circuit in:
- Lambda probe, probe wire, earth wire, engine control unit

 

 

Constant 0.000 V

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

 

 

Significance of figures in 8 digit number block, display zone 4 - Adjustment conditions

X

X

X

X

X

X

X

X

Signifies

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Coolant temperature
0 = Coolant temperature above 80 C
1 = Coolant temperature below 80 C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Engine speed
0 = Engine speed below 1800 rpm
1 = Engine speed above 1800 rpm

 

 

 

 

 

 

 

 

 

 

 

 

Throttle valve
0 = Throttle valve closed
1 = Throttle valve open

 

 

 

 

 

 

 

 

 

 

Lambda control
0 = Lambda control OK.
1 = Fault in the Lambda control

 

 

 

 

 

 

 

 

Idling switch (F60)
0 = Idling switch closed
1 = Idling switch open

 

 

 

 

 

 

Air conditioner compressor
0 = Air conditioner compressor switched off
1 = Air conditioner compressor switched on

 

 

 

 

Gearbox intervention during gear shift
0 = No intervention
1 = Intervention

 

 

Fault memory
0 = No fault stored in fault memory
1 = Fault stored in fault memory

Note on 2nd position in 8 digit number block:

Because the signal is very short, the command to retard the ignition timing is not always recognised by the fault reader V.A.G. 1551 or the vehicle system tester V.A.G 1552. Check gearbox intervention signal when a gear is selected.

Note on 4th and 6th position in 8 digit number block:

If a 1 is displayed here the fault can be that the accelerator cable is too taut.

Note on 5th position in 8 digit number block:

All faults will not be recognized by the self-diagnosis. If a 1 is shown here you must check the Lambda probe and Lambda control even if no fault is stored in the fault memory

 

Display group 2 -Basic functions-

Read measured value block 2

?

[ltrif ] Indicated on display

 

 

 

 

xxxx rpm

xx.xx ms

xx.x V

xxx C

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Intake air temperature

15...70C

---

 

 

 

 

 

 

Supply voltage for
engine control unit

12...14.5 V

 

 

 

 

 

Injection period (per Otto cycle)
Engine code AFK
Engine code AHW


2.00...5.00 ms
2.40...6.00 ms


 

 

 

Engine speed (idling speed)
Engine code AFK
Engine code AHW with manual gearbox
Engine code AHW with automatic gearbox


790...890 rpm1)
800...900 rpm1)
630...730 rpm1)


 

Note on display zone 1:

The idling speed will be increased by the control unit under the following conditions:

  • When the battery voltage is too low: up by approx. 150 rpm.
  • After a long full throttle drive and high temperatures: up by approx. 125 rpm.
  • After starting the engine when intake air temperature is above 75 C or coolant temperature is above 105 C: up by approx.       70 rpm.
  • The idling speed is raised to 750 rpm at selected driving range.
  • With air conditioner switched on, the idling speed is raised to 890 rpm (engine code AFK) or 800 rpm (engine code AHW).

Note on display zone 4:

As soon as a fault is stored in the fault memory which affects the intake air temperature sender (G42), the engine control unit will          use a replacement value of 45 C for the temperature value.

Evaluating display group 2, display zone 2 - Injection period (per Otto cycle)

Appears on display

Possible fault cause

Fault elimination

Lower than
specification

- Large amount of fuel from the activated charcoal filter system

- Check solenoid valve 1
 

 

 

- Incorrect injectors with greater throughput installed

- Check injectors

Higher than
specification

- Increased engine load due to electric consumers, air conditioner, gear selected or P.A.S. steering on full lock

- Eliminate increased load (air conditioner, power assisted steering etc.)

 

 

- Incorrect injectors with smaller throughput installed

- Check injectors

Evaluating display group 2, display zone 3 - Control unit voltage supply

Appears on display

Possible fault cause

Fault elimination

Less than 12.0 V

- Alternator defective, battery charge state low

- Check alternator and battery voltage, charge battery:
=> Electrical system: Repair group 27

 

 

- Battery heavily charged shortly after starting due to high charging current and current consumers

- Increase revs slightly for a few minutes and switch off current consumers

 

 

- Transfer resistance in the current supply or the engine control unit earth connection

- Check engine control unit voltage supply

 

 

- Current draw when ignition is off

- Eliminate current draw

More than 14.5 V

- Voltage regulator on alternator defective

- Check voltage regulator, replace if necessary:
=> Electrical system; Repair group 27

 

 

- Excess voltage due to jump starting or quick charging unit

- Interrogate fault memory
 

 

Display group 3 -Basic functions-

Read measured value block 3

?

[ltrif ] Indicated on display

 

 

 

 

xxxx rpm

xxx %

xxx <

xxx.x %

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Throttle valve positioner duty cycle

Not for
Service department

---

 

 

 

 

 

 

Throttle valve angle
Engine code AFK
Engine code AHW


0...4 <
0...7 <

 
 

 

 

 

Engine load
Engine code AFK
Engine code AHW


16...28 %
15...36 %

 
 

 

Engine speed (idling speed)
Engine code AFK
Engine code AHW with manual gearbox
Engine code AHW with automatic gearbox


790...890 rpm1)
800...900 rpm1)
630...730 rpm1)

 

 

 

Display group 4 -Engine operating condition-

Read measured value block 4

?

[ltrif ] Indicated on display

 

 

 

 

xxxx rpm

xxx %

xxx km/h

xxxxxxxx

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Engine operating condition

01000000

 
 

 

 

 

 

 

Road speed

0 km/h

---

 

 

 

 

Engine load
Engine code AFK
Engine code AHW


16...28 %
15...36 %

 
 

 

Engine speed (idling speed)
Engine code AFK
Engine code AHW with manual gearbox
Engine code AHW with automatic gearbox


790...890 rpm1)
800...900 rpm1)
630...730 rpm1)


 

Note on display zone 1:

The idling speed will be increased by the control unit under the following conditions:

  • When the battery voltage is too low: up by approx. 125 rpm.
  • After a long full throttle drive and high temperatures: up by approx. 125 rpm.
  • After starting the engine when intake air temperature is above 75 C or coolant temperature is above 105 C: up by approx.       70 rpm.
  • The idling speed is raised to 750 rpm at selected driving range.
  • With air conditioner switched on, the idling speed is raised to 890 rpm (engine code AFK) or 800 rpm (engine code AHW).

Notes on display zone 2:

  • The maximum engine load decreases by about 10 % per 1000 m above sea level.
  • The engine load also decreases by up to 10 % if the ambient temperatures are very high.

Note on display zone 3:

Checking speed signal

Note on display zone 4:

Checking engine operating condition

Significance of figures in 8 digit number block, display zone 4 - Operating conditions

X

X

X

X

X

X

X

X

Signifies

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Not relevant

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Not relevant

 

 

 

 

 

 

 

 

 

 

 

 

Not relevant

 

 

 

 

 

 

 

 

 

 

Not relevant

 

 

 

 

 

 

 

 

1 = Full throttle

 

 

 

 

 

 

1 = Part throttle

 

 

 

 

1 = Idling

 

 

1 = Overrun

   

Display group 5 -Throttle valve control part operating conditions

Read measured value block 5

?

[ltrif ] Indicated on display

 

 

 

 

xxxx rpm

xxx.x %

x.xx l/h

xxxxxxxx

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Throttle valve control part operating conditions

00000000

 
 

 

 

 

 

 

Fuel consumption
Engine code AFK
Engine code AHW


0.40...0.90 l/h
0.40...0.80 l/h

---

 

 

 

 

Activated charcoal filter solenoid valve 1 duty cycle

0.0...19.0 %

---

 

 

Engine speed (idling speed)
Engine code AFK
Engine code AHW with manual gearbox
Engine code AHW with automatic gearbox


790...890 rpm1)
800...900 rpm1)
630...730 rpm1)


 

Note on display zone 1:

The idling speed will be increased by the control unit under the following conditions:

  • When the battery voltage is too low: up by 900 rpm.
  • After a long full throttle drive and high temperatures: up by approx. 150 rpm.
  • After starting the engine when intake air temperature is above 75 C or coolant temperature is above 105 C: up by approx.        70 rpm.
  • The idling speed is raised to 750 rpm at selected driving range.
  • With air conditioner switched on, the idling speed is raised to 890 rpm (engine code AFK) or 800 rpm (engine code AHW).

Note on display zone 2:

Check activated charcoal filter solenoid valve 1 (N80)

Notes on display zone 3:

  • The specification is only valid for an idling speed which is not loaded due to ancillaries (e.g. automatic gearbox, air conditioning/heating, alternator, P.A.S. pump).
  • ltr./100 km not suitable for fuel consumption measurement.

Note on display zone 4:

Check throttle valve control part

Significance of figures in 8 digit number block, display zone 4 - Throttle valve control part operating conditions

X

X

X

X

X

X

X

X

Signifies

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Idling switch (F60), during basic setting
0 = Idling switch closed
1 = Idling switch open

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Voltage between throttle valve potentiometer (G69) and
throttle valve positioner potentiometer (G88)
0 = Voltage within tolerance
1 = Voltage outside the tolerance

 

 

 

 

 

 

 

 

 

 

 

 

Signal between throttle valve potentiometer (G69) and
throttle valve positioner potentiometer (G88)
0 = Plausible signal
1 = Implausible signal

 

 

 

 

 

 

 

 

 

 

Idling switch (F60), before the basic setting
0 = Idling switch closed
1 = Idling switch open

 

 

 

 

 

 

 

 

Speed signal
0 = No speed signal recognised
1 = Speed signal recognised

 

 

 

 

 

 

Battery voltage
0 = Battery voltage OK.
1 = Battery voltage too low

 

 

 

 

Not relevant

 

 

Not relevant

 

Display group 6 -Basic functions-

Read measured value block 6

?

[ltrif ] Indicated on display

 

 

 

 

xxx.x %

---

---

xxx <

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Value stored for the throttle valve potentiometer position during the basic setting of the throttle valve control part: Throttle valve closed

Not for
Service department

---

 

 

 

 

 

 

Vacant

---

---

 

 

 

 

Vacant

---

---

 

 

Mixture correction

Not for
Service department

---

 

Display group 098 -Matching throttle valve control part-1)

Read measured value block 98

?

[ltrif ] Indicated on display

 

 

 

 

x.xxx V

x.xxx V

Text

Text

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

Adapting mode

ADP. is running or
ADP. OK. or
ADP ERROR

---

 

 

 

 

 

 

Engine operating mode

Idling or part
throttle

---

 

 

 

 

Throttle valve positioner potentiometer voltage (G88)

0.500...5.000 V

---

 

 

Throttle valve potentiometer voltage (G69)

0.500...5.000 V

---

Note on display group 98:

The throttle valve control part will be matched to the engine control unit when the display group 98 under function 04 "Basic setting" is selected. This matching must always be carried out when a different throttle valve control part (or other complete engine) or a different engine control unit is fitted.

If the voltage supply is interrupted (battery disconnected), adaptation need not be performed.

Display group 125 -Communication -data bus messages-

? Engine running at idling speed

Read measured value block 125

?

[ltrif ] Indicated on display

 

 

 

 

Text1)

Text

Text2)

 

 

 

 

 

 

 

 

1

2

3

4

[ltrif ] Display zones

Specification

Evaluation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Airbag status

Airbag 1

---

 

 

 

 

Combi status

Combi 1

---

 

 

ABS status

ABS 1

---

1)    Only displayed when ABS is coded

2)    Only displayed when airbag is coded

Note on display group 125:

If specification = 1, the display indicates that data bus is active.