Repair manual

Engine Mechanicals
13
Self-Diagnostics
The engine self-diagnostics check the mechanical
function of the cam adjustment actuators (changeover to
the other cam lobe contour) and the system’s electrical
connections.
A system test is performed after the engine is started.
The ECM activates each actuator for this purpose.
Both configurations are tested and evaluated. This
system test is audible and is performed whenever
the engine is started. System failure will result in
corresponding DTC entries.
Depending on the nature of the fault, the driver may
notice a slight variation in engine idling speed or a
different engine response under acceleration.
How the System Responds to Faults
If one or more actuators fails, the ECM will initially
attempt (several times) to change over to the other cam.
If no adjustment is made, the cam elements that cannot
be adjusted remain in position.
All other cam elements are changed over to the large
cam. They then remain in this position while the engine
is running. The next time the engine is started, another
attempt is made to adjust all cam elements.
Activation of the Warning Lamps
Exhaust emissions do not deteriorate due to system
failure and because virtually no adverse handling
effects may result, neither Electronic Power Control
Warning Lamp K132 nor Malfunction Indicator Lamp K83
is activated. However, corresponding DTC entries are
generated.
01 - Engine electronics
EV_ECM20AVS_X1
Vehicle self-diagnostics
004.01 - Interrogate fault memory
1 Fault detected
Text
Cam adjuster “A”, cylinder 1
Electrical fault/open circuit
SAE code
P11A100
Status
active/
static
Ambient
conditions