Automotive electronics.pdf

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Our Ideas,
Your Success.
Automotive electronics
What you need to know! Part 1
Ideas today for
the cars of tomorrow
Secure your future – with vehicle electronics from Hella!
The proportion of electronics in vehicles increases constantly – it is estimated that in the year 2010, it
will be approximately 30% of the entire material value of a vehicle. This poses a growing challenge to
garages, and changes the original business – from the traditional maintenance service to the service-
oriented high-tech garage. Hella would like to support you. Therefore, our electronics experts have put
together a selection of important information on the subject of vehicle electronics.
Hella offers a vast product range for vehicle electronics:
• Air mass sensors • Air temperature sensors/sender units (intake,interior & exterior) • Brake wear
sensors • Camshaft position sensors • Coolant temperature sensors/sender units • Coolant level
sensors • Crankshaft pulse sensors • Engine oil level sensors • Idle actuators • Knock sensors,
MAP sensors • Oxygen sensors • Speedometer sensors • Throttle position sensors • Transmission
speed sensors • Wheel speed sensors (ABS)
We are sure you will find our booklet of great help in your daily business. For further information please
consult your Hella sales representative.
2
Index
General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Table of contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Basics
Diagnosis work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Troubleshooting using the oscilloscope
. . . . . . . . . . . . . . . . .11
Troubleshooting using the multimeter . . . . . . . . . . . . . . . . . . .16
Sensors
Crankshaft sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Intake air temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . 31
Coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . .33
Transmission sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Wheel speed sensor (ABS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Knock sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Mass air flow meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Camshaft sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Accelerator pedal sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Throttle potentiometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Throttle valve switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Actuator technology
Fuel injectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Idle speed stabilisers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Systems
The engine control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
The ABS braking system . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
The exhaust gas recirculation system . . . . . . . . . . . . . . . . . . . 68
Activated carbon canister . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
The ignition systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
CAN-bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Tyre pressure control system . . . . . . . . . . . . . . . . . . . . . . . . . 99
Notes
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106 - 107
3
Basics:
Diagnosis work
We are going to inform you about testing and diagnosis units, trouble-
shooting and how to obtain technical information.
Testing and diagnosis units
Let us start with the necessary testing and diagnosis units. To be able to
carry out efficient troubleshooting on vehicles these days, it is important to
have the right testing and diagnosis equipment available. These include:
■
Multimeter
■
Oscilloscope
■
Diagnosis unit
The multimeter is probably the one measuring instrument most often used
in the garage. It can be used for all quick voltage or resistance measure-
ments. A practical multimeter should meet the following minimum require-
ments:
■
DC V= various measuring ranges for direct voltage (mV, V)
■
DC A= various measuring ranges for direct current (mA, A)
■
AC V = various measuring ranges for alternating voltage
■
AC A= various measuring ranges for alternating current
■
Ω
= various measuring ranges for resistance
■
= continuity buzzer
As an additional option we recommend taking the measuring ranges for
temperature and frequency into consideration as well. The input
resistance should be a minimum of 10 MΩ.
Multimeter
An oscilloscope is required for recording and representing different sensor
signals. An oscilloscope should meet the following specifications:
■
2 channels
■
Minimum 20 MHz
■
Store and print images
As an additional option here we recommend the possibility of automatic
image sweep (recording and reproduction). A portable hand-held unit is
sensible for more straightforward application at the vehicle.
Oscilloscope
4
Basics:
Diagnosis units are becoming more important all the time in day-to-day
garage work. For these to be able to be used properly, they should also
have several basic functions:
■
Read out fault codes, with plain text display
■
Clear fault codes
■
Indicate measured values
■
Actuator test
Diagnosis unit
In
■
■
■
■
■
■
addition there are useful options that must be taken into consideration:
The device should be easy to transport.
Large market-specific cover of vehicle makes and models.
Resetting and reprogramming of service interval displays.
The unit should have the possibility of coding e.g. control units.
Data transfer via PC/printer should be possible.
Updates should be able to be installed as easily as possible.
Before a decision is taken in favour of one particular diagnosis unit, it
makes sense to have a look at several units from different manufacturers
and perhaps to test a demonstration unit in day-to-day garage work. This
is the best way to test handling and practicability aspects.
In addition, the following factors need to be considered:
What is the vehicle cover of the unit like?
Does this match the customer vehicles the garage has to deal with?
Have a look at the makes of your customers' vehicles and compare these
with the vehicle makes stored in the unit. If you have specialised on one
make, you should definitely make sure this is stored. The complete model
range of the vehicle manufacturer, including the respective engine ver-
sions, should also be available of course. Other decisive factors include
the testing depth and individual vehicle systems (engine, ABS, air condi-
tioning etc.) which can be diagnosed in individual vehicles. If there is a
wide range of vehicle makes stored in the unit this does not automatically
mean that the same diagnosis standard can be assumed for all vehicles.
How are updates transferred to the unit?
Again, there are different possibilities here. Updates can be carried out via
the Internet, CD or memory expansion boards. In this case, every unit
manufacturer has his own philosophy. What is of interest is how frequently
updates take place and how comprehensive these are.
What additional information is offered?
A series of diagnosis unit manufacturers offers a wide range of additional
information. This includes technical information such as circuit diagrams,
installation locations for components, testing methods etc.. Sometimes
information about vehicle-specific problems or customer management
problems is also provided.
5

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