An ordinary car user with a DPF filter will never have to deal with DPF error codes. A mechanic is different matter. For him, diagnostic trouble codes (DTCs) are a mine of knowledge, what is wrong with the car or its subassemblies. When internal sensors detect an abnormality or deviation from the norm, they transmit the code to the on-board computer diagnostic system (OBD).
Types of DTC error codes
Everything in the world tends to standardize. The international standards SAE and ISO have been in force since 2000 for car manufacturers, which unify OBD codes (the European version is EOBD). Therefore, the mechanic, independent of the manufacturer or the vintage, knows immediately what the defect is about.
Each code consists of five characters. The first letter symbolizes the location of the failure, the first digit says whether it is a generic fault or manufacturer fault.
B – body
C – chassis
P – engine
U – communication system
The next three digits are responsible for the location in a particular car system and the type of error. For example in code P:
0, 1 and 2: for the air/fuel mixture
3 : for the ignition system
4 : for checking auxiliary emissions
5 : for engine idling
6 : for the onboard computer and ancillary outputs
7, 8 and 9: for the transmission (gearbox)
- A, B and C : for hybrid propulsion
Is the DTC error code a full diagnosis?
The DTC error codes is just the beginning of the diagnosis. It should be verified with the vehicle’s operating instructions, because some codes (P1) are sometimes specific to the manufacturer.
When the diagnostic system indicates a component failure, check several components. The sensor itself, which sends false data or its cabling, could have been damaged. When the sensor is functional, it is necessary to see the whole sequence of the system. It is possible that a part has been broken which affects further elements and the DTC error code applies to the latter. For example, a dirty air flow sensor affects fuel-trim adjustments. In this situation, the air sensor will indicate problems with the fuel mixture.
DPF error codes
Also, each of DPF error codes can have many causes and therefore each case must be considered individually.
We have included specific codes in a separate article. There is no one, top-down and always working procedure. The repair is based more on the mechanics’ experience and diligence. A entire exhaust system is quite complicated and it is not always possible to clearly indicate what and why it failed.
The first step should be to look through technical service bulletins (TSBs) for a specific car model. Certain errors are popular and manufacturers make commonly available corrections. This will help you save time when diagnosing.
If this does not help, look at the exhaust system thoroughly, not just the DPF filter itself.