Designation of Trouble Codes

Designation of trouble codes

The diagnostics tool VIDA shows the diagnostic trouble code in plain text according to the following example:
TCM-001F Speed sensor Signal missing Permanent malfunction

This diagnostic trouble code consists of the following parts:
- Prefix for control system in question ( TCM) to show what system the diagnostic trouble code belongs to. *
- Diagnostic trouble code number ( 001F) to decide which diagnostic trouble code is stored. Number of digits in the diagnostic trouble code number may vary. *, **
- Title ( Speed sensor) is a text that shows to which component/function the diagnostic trouble code refers. *
- Qualifier ( Signal missing) is used to show how the control module has perceived the signal from, e.g., the sensor, or how it detected the monitored function. In this case, the control module has perceived that the signal is missing. There a re a number of other qualifiers for, e.g., too high signal, incorrect signal, too high flow, too low flow, etc. *, **.
- If the qualifier is, e.g., "Too high signal", the control module interprets that the signal from the sensor is too high. This may mean that, e.g., the voltage is too high, current is too high, frequency is too high, or the pulse ratio (% duty) is too high, all depending on which type of signal it is. Malfunction causes may be, e.g., open circuit or short-circuiting to voltage.
- If the qualifier is "Too low signal", the control module interprets that the signal from the sensor is too low. Malfunction causes may be, e.g., open circuit, shirt-circuiting to ground, contact resistance in connections.
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Note! Information about which type of signal that the control module detects and what conditions are required to detect that a malfunction is found again in the diagnostic trouble code information.

- Status ( Permanent malfunction) to show the malfunction's status, that is, if the malfunction has been detected in the present driving cycle or not. There are two different status texts, permanent or intermittent. When the control module's diagnosis cannot decide the malfunction's status, the diagnostic trouble code is shown without status text. *
* When reading out diagnostic trouble codes using diagnostic socket with light-emitting diode, you get a three-digit flash code. Then this code is translated to a diagnostic trouble code text using the service information.
For example, if the control module flashes the code 1-2-3 from Engine control module (ECM), it can be translated to, e.g., diagnostic trouble code 1-2-3 Engine temperature sensor. Volvo Diagnostic Key and Volvo System Tester translate these flash codes directly to plain text (add a title). In these diagnostic systems it is not possible to show qualifier or status.
** For systems with diagnostic version called Generic Global Diagnostics (GGD) (adheres to standard ISO/DIS 15031-6.4) the diagnostic trouble code number consists of a letter and six characters. The letter alternatives are B, C, P and N, which means Body, Chassis, Powertrain and Network and indicate to which "function" in the vehicle the diagnostic trouble code belongs. The six following characters may consist of both letters (A-F) and digits (0-9) and indicate the component to which the malfunction refers as well as what type of malfunction. See following example.
BCM-C006A16 Multi-axial acceleration sensor. General electric malfunction. Too low voltage