Note: See also Section "Troubleshooting" Introductions.
1. Ignition and power systems are interrelated components of the engine management system, so some of its components may also perform functions related to the power system.
2. When a failure is detected, the control unit writes to the memory the corresponding DTC code, which can be read using a special scanner.
Note: Do not forget to clear the memory of the control unit after reading the fault codes and making the appropriate corrections.
3. Reading the information stored in the ECM memory, in most cases, allows you to determine the causes of engine malfunctions. Analysis of read information using a list of codes (see specs) allows you to localize the source of failure at the level of a particular element, or its electrical wiring circuit.
Attention: A visual check of the wiring and connectors is not enough - be sure to read the information stored in the memory of the control unit!
4. DTCs are five digit codes and can be identified by their alphanumeric structure. The code structure is described below using the example of P0401 (EGR adjustment, too much air mass):
1st sign P - engine and transmission (Powertrain)
B - body (Body)
C - running gear (Chassis)
U - data transmission systems
2nd character 0 - standardized code (SAE/ISO)
1 - code assigned by the manufacturer
2 - standardized code (SAE/ISO)
3 - distributed area for standardized codes (SAE/ISO) and for codes assigned by the manufacturer
3rd character 0 - dosing of fuel and air supply, additional equipment that reduces exhaust gas toxicity
1, 2 - dosing of fuel and air supply
3 - ignition system (petrol models)
4 - additional equipment that reduces exhaust gas toxicity
5 - driving speed, idle parameters and other input data
6 - on-board computer and other output data
7-9 - gearbox
A - combined drive
4th and 5th characters sequential numbering of individual nodes or systems