Measured Value Blocks

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...70°C	---
			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.