Table of contents: Examination 🠇 Adjustment 🠇
Examination
1. If a malfunction occurs in the engine management system, first check that all electrical connectors in the system are securely connected and that they are not corroded. Make sure that the malfunction is not due to poor maintenance. It is necessary to check the cleanliness of the air filter element, the condition of the spark plugs, the interelectrode gaps in them and the compression in the engine cylinders. Also check the engine ventilation hoses for dirt or damage. For more information, please refer to the chapters 1A, 2A and 5B.
2. If these checks do not reveal the cause of the problem, take the vehicle to a Peugeot/Citroen dealer or an engine management system diagnostic specialist with the appropriate equipment. Next to the passenger compartment fuse box is a diagnostic connector to which you can connect a trouble code reader or other specialized electronic testing equipment (figure 11.2). The test equipment can "query" the electronic control unit (ECU) of the engine management system (electronic control units of other vehicle systems) and provides access to the internal fault memory of the ECU for reading fault codes. Using such equipment, you can quickly and easily identify the causes of a malfunction, even if they only occur from time to time. Checking all the system elements separately when trying to identify a fault by the elimination method is a rather lengthy procedure and is unlikely to be fruitful (especially if the malfunction does not always appear). In addition, this entails a high degree of risk of damage to the internal components of the electronic control units.
Figure 11.2. Diagnostic connector (marked with an arrow) located next to the passenger compartment fuse box
Adjustment
3. An experienced, non-professional mechanic with sufficient experience and the necessary equipment can check the CO level in the exhaust gases and determine the crankshaft speed in idle mode. If these parameters are not within the normal range and require adjustment, you should contact your dealer or other specialist with the appropriate equipment to diagnose the vehicle. Neither the composition of the air-fuel mixture (cO content in exhaust gases), neither the idle speed nor the crankshaft rotation speed can be adjusted manually. Unsatisfactory test results indicate a malfunction in the engine management system.