Diagnostics And Services
Diagnostics and services
General
The control module's diagnostics can perform and present the following using a connected diagnostics tool:
- Store malfunction indicator (diagnostic trouble codes) and in certain cases activate warning light or show text message.
- Store information about the nature of the malfunction:
- Counter that indicates how frequent the malfunction is
- Status indicators for the diagnostic trouble code test.
- Frozen values that were generated when malfunction was detected for the first time.
- Erase information about malfunction and its information.
- Present values (parameters) for different connected input signals and output signals from, e.g., components as well as other calculated values.
- Present part number, version number, component number, etc. for both software and hardware.
- Present and change certain special customer settings and configurations.
- Trigger/control (activate) the connected output signals.
- Start special built-in check programs/tester such as, e.g., calibrations of gear position sensor, quick-test of tank system.
- Access check to limit access to certain parameters and functions. Accessible first after unlocking with, e.g., PIN-code.
Exactly what each control module's diagnostics can perform depends both on model year and system.
Diagnostic trouble codes (malfunction indicator)
- General General
- Conditions for diagnosis to find a malfunction Conditions For Diagnosis To Find A Malfunction
- Driving cycle/operation cycle Monitors, Trips, Drive Cycles and Readiness Codes
- Emergency mode, back-up mode "Limp-home" Emergency Mode, Back-Up Mode "Limp-Home"
- Classification of diagnostic trouble codes Classification Of Diagnostic Trouble Codes
- Designation of trouble codes Designation Of Trouble Codes
- Status identifier Status Identifier
- Counter Counter
- Frozen values Scan Tool Testing and Procedures
- Erasing diagnostic trouble codes Erasing Diagnostic Trouble Codes
- Readiness Monitor (certain markets only) Readiness Monitor (Certain Markets Only)
Parameters
Parameters or values are data that are read out from the control module's memory positions to, e.g., check the signal from a sensor or identify the control module's software version.
In principle, parameters can be divided into two parts:
- one for dynamic values continuously updated in the control module
- one for static values not changed by the control module and always stored.
Parameters, dynamic
The dynamic values are stored in the control module's RAM-memory, which means that the values disappear when the memory's power supply is turned off (control module is turned off). As soon as the control module's power is turned on (ignition on), values are stored again.
Example of values are:
- Outside temperature
- Engine speed
- Load
- Coolant temperature
- Vehicle speed
- Battery voltage
Values are updated continuously after a pre-determined time interval.This means that certain values are updated with very short time interval, while other values are updated more seldom. Update rate is determined by how important the value is to the control module.
By reading off the value from, e.g., a sensor or switch, it can be decided if the signal is correct or not.
Note! When a malfunction is detected and a diagnostic trouble code is stored, it may well be that the displayed value is a replacement value and not the real value. If the value does not change, e.g., if the sensor is disconnected, it may be the replacement value that is shown.
Parameters, static
The static values are stored in the control module's EEPROM, which means that these values are always stored regardless of if the control module is on or off. These values are normally not updated by the control module, instead they are only changed using, e.g., the diagnostics tool at vehicle manufacture in the factory or reprogramming during a workshop visit.
Example of values are:
- Hardware P/N (control module without software).
- Hardware serial number (control module without software).
- Software P/N.
- Diagnostic software P/N.
- Customer-programmed values, e.g., passenger compartment temperature, alarm on and off.
- The vehicle's configuration, that is, the vehicle's content and equipment that can be used to compare the vehicle's equipment physically with how the vehicle is configured. The configuration may be affected/changed, e.g., when downloading software.
Activations
Wit this service it is possible to trigger (activate) the components that are connected to the control module. Examples of components are:
- Relays
- Solenoids
- Lock motors
- Damper motors
- Signals to other control modules.
Note! If a malfunction is detected, diagnostic trouble code is stored and emergency functions or modes, etc. are activated to "protect" the system, the control module can prevent activation.
Depending on the system, the control module or diagnostics tool can perform activations in different ways, for some the component is activated according to a certain pattern, e.g., OFF, ON, OFF, ON, OF, ON, etc. in a sequence.
For other systems, the component is activated, e.g., ON, and remain on until the activation is stopped.
Quick-tests, calibrations
Quick-tests or calibrations are functions or checks that are integrated in the control module's software and are started by the control module using commands from the diagnostics tool.
Wit this service it is possible to start certain pre-defined checks or teach-ins. Examples of these are:
- Quick-test of fuel tank system
- Quick-test of camshaft control
- Resetting of adaptations and counter for oil
- Calibration of gear position sensor
- Calibration of components for Brake control module (BCM)
Note! To enable start and running of these services, it is often that certain start conditions must be fulfilled.
Software downloading
New software can be downloaded to the control modules. When ordering software the vehicle software and hardware are compared to Volvo's central database. If the comparison corresponds the new software is downloaded to the control module.
If the comparison between the car and Volvo's central database does not correspond, then the database is updated with the vehicle's configuration. When this is complete the software is downloaded.
For further information regarding downloading, see Design and Function, Downloading Software.