AD07.61-P-4000-53B | Fault code description when cylinder cut-out system valve does not open with cylinder cut-out system ON, ME-SFI | Engine 113.960 up to 5/00 with code (479) cylinder cut-out system |
1 | Fault code | |
2 | Fault storage Activation of malfunction indicator lamp for engine diagnosis | after the end of the test period and faults after two successive driving cycles with faults |
3 | Frequency of the test Monitoring period | continuous with cylinder cut-out system ON approx. 5 s after the test prerequisites have been met |
4 | Fault setting conditions | Air mass too large (does not correspond to 4-cylinder engine) |
5 | Test prerequisites | - engine speed approx. 500 - 4500 rpm and constant - mean constant load (intake manifold absolute pressure approx. 200 - 1000 hPa) - cylinder cut-out system released (no fault to) - no fault in hot film mass air flow sensor, crankshaft position sensor, pressure sensor (intake manifold) - no fault in cylinder cut-out system valve (output stages) - no fault in oil pressure or oil level - no misfires "damaging to TWC" - diagnosis for exhaust gas recirculation not active - safety fuel cut-off not active - emergency running throttle valve actuator not active |
6 | Test sequence | With cylinder cut-out system ON, both cylinder cut-out system valves are activated and have to open. Oil pressure arrives at the clamping bolts in the rocker arms and releases the rocker arm coupling. If the intake and exhaust valves of cylinders 2 and 3 (right cylinder bank) or cylinders 5 and 8 (left cylinder bank) are nevertheless still actuated, the air mass taken in by the engine is too large. A defective cylinder cut-out system valve is determined. |
7 | | An additional indication to the defective cylinder cut-out system valve is possible via the lambda control: at the cylinder bank with the defective cylinder cut-out system valve, the cylinders that are actually switched off suck the fresh air away from the other cylinders. The mixture becomes leaner, the oxygen sensor voltage drops and the lambda control reacts by enriching the mixture. |