Fault codes are diagnostic codes sent across the vehicle diagnostic bus when a problem occurs in the engine. To read the codes, Synovia makes an engine diagnostics (ED) connection to the on-board diagnostics (OBD) port, with either a light-duty (such as an LMU-3030 connecting to the OBD2 port) or heavy-duty (such as an LMU-4225 with JPOD) solution.

When a fault code is generated, our equipment reads it and sends it to the Synovia software. The code can be compared to a table explaining what it indicates, unless it is a manufacturer’s proprietary code, in which case the manufacturer may charge for an explanation of the code's meaning. Typically, codes that begin with P0, P2, and P34-P39 are generic codes, whereas codes that begin with P1 and P30-P33 are manufacturer-specific.

Here are some examples of fault codes and what they mean:

Synovia's equipment is always checking for the fault codes. The rate of this checking can be modified, but it can’t be done too frequently (because that can cause motor issues such as transmission locks).

In Synovia, you can set up alerts for when a fault code is detected under System Administration >> Alert Admin, such as OBDII General Fault. See Creating a New Alert for more details.

There is a group of Fault Code reports under Core >> Reports that can give you the number of codes returned by your fleet and details about those codes. See Engine Diagnostics >> Reports for more details.