diagnostic functions.

Design and Function

Applies to: 2011–2013; D5204T, D5204T5

General

The engine control module (ECM) diagnoses both internal signals and functions as well as signals and functions from connected components.

Conditions for diagnosis

For the diagnosis of a component or function to start, certain specific conditions must be met. The conditions for diagnostics vary depending on the component or function being diagnosed.

Conditions must be met during the diagnostic in order for the diagnostic to be completed. The time and conditions for the diagnostic vary depending on the component or function being diagnosed. Certain diagnostics only require the ignition to be switched on and off for a diagnostic to be run. Other diagnostics require that several different conditions are met. For example:

• vehicle speed
• engine coolant temperature (ECT)
• time since start
• different load and engine speed relationships in the same trip
• a certain event (for example the EGR valve is operating).

When the engine control module (ECM) has run all the implemented diagnostics, the control module has completed a "trip". An extensive driving schedule in various conditions is required to complete a trip. The engine may also need to be shut off for a certain amount of time and then switched on again to complete a trip.

Emissions related diagnostic functions

The engine control module (ECM) checks that the emissions related systems are working. These systems are checked by running a diagnostic function. The diagnostic function checks the components and that the system is functioning.

Diagnostic trouble code (DTC) memory

When the engine control module (ECM) detects a fault, the diagnostic trouble code and status are stored in the diagnostic trouble code memory and are visible during normal diagnostic trouble code readout. If the diagnostic trouble code (DTC) lights the malfunction indicator lamp (MIL), this occurs at the same time. If an existing fault disappears and does not recur, the engine control module changes the status of the diagnostic trouble code after a certain number of fault-free operating cycles (depending on the nature of the diagnostic trouble code). This means that it can no longer be read during normal diagnostic trouble code readout. In this status, the diagnostic trouble code remains until the engine control module (ECM) erases diagnostic trouble codes or is disconnected from power.

Substitute value

For certain types of diagnostic trouble codes (DTCs), the missing signal is replaced with a substitute value so that the system can continue functioning.

Applies to: 2011–2013; TF-80SC

General

The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and output signals.

Diagnostic trouble codes (DTCs)

A diagnostic trouble code (DTC) is stored if the control module detects a fault. A fault which is detected in the most recent operating cycle is defined as permanent. Other faults are defined as intermittent. An operating cycle involves ignition on, the vehicle speed exceeding 20 km/h and the ignition being switched off.

Reading and erasing diagnostic trouble codes (DTCs)

Stored diagnostic trouble codes (DTCs) can be read off and erased using this function.

Diagnostic trouble codes (DTCs) can only be erased once all the diagnostic trouble codes (DTCs) have been read off at least once.

Reading off input and output signals

This function can be used to continuously read off the status of the control module's input and output signals.

For more information about parameters, see Vehicle communication information in Specifications, other.

Activating components

This function can be used to activate components to check that they are working.

For more information on activations, see Vehicle communication information under Specifications, other.

Reading off the control module identification

The control module can be identified by means of reading off a number of codes.

The codes contain the following information about the control module:

• hardware P/N (control module without software)
• hardware serial number (control module without software)
• software P/N
• diagnostic software P/N.

Resetting the adaptation values

There are three functions in the software for the transmission control module (TCM) for adaptation which can be activated:

• Resetting adaptation. Must be performed after replacing an internal component or the whole transmission.
• Resetting the gauge for oil degradation.
• Calibration of gear selector in neutral position.

The gear position sensor must be calibrated after check or replacement of the control module to ensure the gear position sensor detects the correct gear selector position.