Motronic M 1.5.4 Quick Check F8:ECU CONTROL
CONTROLLED EGR
| Conditions for Checking | Nominal Value |
Affected Terminals: 23, 19
Possible Trouble Codes: 33, 34
Engine running at idle speed, operating temperature
Engine throttle valve CLOSED (accelerator pedal in idle position)
Press key F8 in the system main menu, select the desired test using the arrow keys and confirm with YES. Follow the instructions in the diagnostic tester display.
Note:
| In this control test, it is possible to open the exhaust gas recirculation valve certain limits. Depending on the size of the opening, more or less exhaust gas is returned to before the cylinders and is then forced back into the cylinders and recombusted the next time the intake valves are opened. If a large amount of exhaust gas is recirculated, the engine does not have enough oxygen for combustion (the O2 sensor tend towards lean, the injection period increases). This leads to jerking. At a exhaust gas recirculation rate of approx. 40% and above this jerking becomes noticeable, and becomes more marked as the recirculation rate increases. At a recirculation rate of approx. 50% and above, the engine jerks considerably and if further increased the engine may stall. |