Frozen Values

For every diagnostic trouble code, pre-defined parameters are frozen and stored in the control module. The frozen values are stored immediately after the malfunction has been detected and gives a "picture" of the conditions when the malfunction was stored.

NOTE:

Status identifier, Counter and Frozen values are the most important factors to deciding the malfunction's nature, that is, to decide:

when the malfunction was detected (frozen values, counters)
what the driving conditions were at the time (frozen values)
status for the test (self-diagnosis) (status identifier)
how frequent the malfunction is (counter).

In newer car models, frozen values consist of a number of global (common) general parameters as well as a number of control model-unique parameters. Global may be:

Road distance
Battery voltage
Passenger compartment temperature
Outside temperature
Engine running

In addition to these, the diagnostic trouble code-unique parameters are stored which are especially selected parameters for the diagnostic trouble code.

Most parameters in the frozen values are the same for all malfunctions and indicate a general condition when a malfunction was detected, for example:

Road distance
Outside temperature
Engine speed
Load
Coolant temperature
Vehicle speed
Battery voltage
etc.

Some of them have been selected to give a better understanding of the specific malfunction.

NOTE:

When erasing diagnostic trouble codes, stored frozen values are also erased.

HINT: Reading out and interpreting these frozen values make it easier to understand when in time the malfunction occurred, as well as under what driving and environment conditions the malfunction was detected, related to when and how the customer experienced the symptom.