Specifications

49
Data Parameters Engine Parameters
parameter name indicates twelve separate parameters, one for each cylinder. The display reads
OFF when fuel injection is suspended and ON during normal fuel injection operation.
CYLINDER SHUT-OFF 1 to 12
CYLINDER SHUT-OFF VALVE, RIGHT
CYLINDER SHUT-OFF VALVE, LEFT
Range: __________________________________________________________ ON/OFF
Used on ME27 (V12) and ME28 systems. These parameters indicate whether or not cylinder
operation has been suspended to reduce fuel consumption during certain cruise conditions. The
“1 to 12" in some of the parameter names indicate up to twelve separate parameters, one for
each cylinder. The display reads OFF when a cylinder or engine bank has been shut down. It
reads ON if that cylinder or bank is in normal operation. For those cylinders or bank shut-off, fuel
injection is eliminated and ignition spark is drastically reduced. For the ME27 V12 engine,
cylinder shutoff may disable up to 6 cylinders, usually all on the left engine bank (cylinders 7-12),
depending on engine load requirements. Cylinder shutoff starts with the number 7 cylinder or the
number 12 cylinder. Exhaust valves are shut off first, followed by the intake valves. This
maintains exhaust gas pressure in the cylinder, preventing crankcase oil from being drawn up
due to vacuum. Oil pressure is used to operate coupling valve levers which can engage or
disengage rocker arms. In the disengaged mode, valves do not open and remain permanently
closed during cylinder shutoff operation.
On ME28 engines, complete left or right engine bank is disabled using ME-controlled solenoids
that disable all the valves on one bank simultaneously.
DAS AND DSV MODULES ARE MATCHED
DAS AND ECM COMPATIBLE
DAS AND ENGINE CTRL. MOD. COMPATIBLE
Range: __________________________________________________________ YES/NO
DAS CONTROL MODULES
Range: _______________________________________________________ OK/NOT OK
Used on ERE/EVE/ASF (IFI Diesel)), ME10 and ME20 systems. These parameters show if the
drive authorization system (DAS) or anti-theft system and the ECU have correctly identified each
other at startup. The display reads YES if the modules identify each other and NO if they do not.
The ECU and DAS module are permanently interlocked, after a fixed number of starts when
replacing the ECU, by an identification code that cannot be erased. Therefore, it is not possible
to interchange modules from another vehicle for test purposes. Interchanges can only be done
with a matched pair of modules. The ME-SFI module has an immobilizer. When the vehicle is
locked, the DAS sends a signal to the ME-SFI that inhibits injection. Engine starting is prohibited
unless the authorized key is used and a start enable signal from the DAS module is received by
the ME-SFI module.
DECELERATION
Range: __________________________________________________________ YES/NO
DECELERATION SHUT-OFF
Range: __________________________________________________________ ON/OFF
Used on DM2, EGS, HFM, LH, ME10 and ME20 systems. These parameters indicate whether
the ECU has temporarily shut off fuel injection during deceleration to reduce emissions. The
display reads ON or YES if the ECU commands the injectors off during deceleration, and reads
OFF or NO at all other times.
Certain conditions must be met to activate: engine coolant temperature must be above 122°F
(50°C), engine speed must be above 2100 RPM, and vehicle speed over 22 mph. The ECU
recognizes deceleration when the throttle valve position is less than that required for a specific
engine speed, or when the ECU senses closed throttle idle contacts. Once RPM drops to 1000,
the injectors switch back on. The ignition timing is momentarily retarded to avoid a power surge.