Page 1405 of 4133

See MODULATING PRESSURE, FUNCTION
.
Shift Valve Pressure, Function
See SHIFT VALVE PRESSURE, FUNCTION
.
Lubricating Pressure, Function
See LUBRICATING PRESSURE, FUNCTION
.
Regulating Valve Pressure, Function
See REGULATING VALVE PRESSURE, FUNCTION
.
Limp-Home Mode, Function
Operation
In order to ensure a safe driving state and to prevent damage to the automatic transmission, the ECT control
module (N15/3) switches to limp-home mode in the event of critical faults. A fault code assigned to the fault is
stored in memory.
All solenoid and regulating valves are thus de-energized.
Effect
The gear last engaged remains engaged.
The modulating pressure and shift pressure rise to the maximum levels.
The torque converter lockup clutch is switched off.
In order to preserve the operability of the vehicle to some extent, the hydraulic control can be used to engage
2nd gear or reverse:
Stop Vehicle
Switch Off Engine
Move Selector Lever To "P"
Wait At Least 10 Seconds
Start Engine
Move Selector Lever To "D": 2Nd Gear
Move Selector Lever To "R"
The limp-home function remains active until the fault is rectified or the stored fault code is erased. Sporadic
faults can be reset via ignition OFF/ON.
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 236 © 2006 Mitchell Repair Information Company, LLC.
Page 1406 of 4133

Upshift/Downshift Solenoid Valve, Location/Design/Task/Function
See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch
See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function
See MODULATING PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Shift Pressure Regulating Solenoid Valve, Location/Task/Design/Function
See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Operating Pressure, Function
The working pressure supplies pressure to the hydraulic control and transmission elements. The working
pressure is the highest hydraulic pressure in the entire hydraulic system. The working pressure is regulated at
the working pressure regulating valve in relation to the load and gear. All other pressures required for
transmission control are diverted from the working pressure.
Working Pressure Regulating Valve, Location/Task/Function
See WORKING PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function
See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Shift Pressure Control Solenoid Valve, Location/Task/Design/Function
See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Multiple-Disc Brake, Location/Task/Design/Function
See MULTIPLE
-DISC BRAKE, LOCATION/TASK/DESIGN/FUNCTION.
Multiplate Clutch, Location/Task/Design/Function
See MULTI
-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Page 1407 of 4133

Holding Pressure Shift Valve, Location/Task/Design/Function
See HOLDING PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Shift Pressure Shift Valve, Location/Task/Function
See SHIFT PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function
See OVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Location/Task/Function Of Command Valve
See LOCATION/TASK/FUNCTION OF COMMAND VALVE
.
Selector Valve, Location/Task
See SELECTOR VALVE, LOCATION/TASK
.
Location/Task/Design/Function Of Oil Pump
See LOCATION/TASK/DESIGN/FUNCTION OF OIL PUMP
.
Lubricating Pressure, Function
Operation
The working pressure regulating valve diverts surplus oil to the lubrication pressure regulating valve, from
where it is controlled and used for lubricating and cooling the mechanical transmission and torque converter. In
addition the pressure in the torque converter is limited via the lubrication pressure.
Working Pressure Regulating Valve, Location/Task/Function
See WORKING PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Lubrication Pressure Regulating Valve, Location/Task/Function
See LUBRICATION PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Torque Converter Lockup Clutch Regulating Valve, Location/Task/Function
See SHIFT PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function
See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:29 PMPage 238 © 2006 Mitchell Repair Information Company, LLC.
Page 1409 of 4133

as regulated by the overlap regulating valve.
Initializes 2nd gear in limp-home mode.
Shift Pressure Regulating Solenoid Valve, Location/Task/Design/Function
See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Shift Pressure Regulating Valve, Location/Task/Function
See SHIFT PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function
See OVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function
See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function
See MODULATING PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch
See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
Multiple-Disc Brake, Location/Task/Design/Function
See NMULTIPLE
-DISC BRAKE, LOCATION/TASK/DESIGN/FUNCTION.
Multiplate Clutch, Location/Task/Design/Function
See MULTI
-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.
Holding Pressure Shift Valve, Location/Design/Function
See HOLDING PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Shift Pressure Shift Valve, Location/Design/Function
See SHIFT PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Command Valve, Location/Design/Function
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Page 1410 of 4133

See LOCATION/TASK/FUNCTION OF COMMAND VALVE
.
Selector Valve, Location/Task
See SELECTOR VALVE, LOCATION/TASK
.
Location/Task/Design/Function Of Oil Pump
See LOCATION/TASK/DESIGN/FUNCTION OF OIL PUMP
.
Modulating Pressure, Function
Operation
The modulating pressure influences the size of the working pressure and determines together with the shift
pressure the pressure regulated at the overlap regulating valve.
The modulating pressure is regulated at the modulating pressure regulating solenoid (Y3/6y1), which is under
regulating valve pressure. The modulating pressure via variable and relative to the engine load.
Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function
See MODULATING PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Working Pressure Regulating Valve, Location/Task/Function
See WORKING PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function
See NOVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function
See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
Shift Pressure Control Solenoid Valve, Location/Task/Design/Function
See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch
See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 241 © 2006 Mitchell Repair Information Company, LLC.
Page 1415 of 4133

Shift Pressure Shift Valve, Location/Task/Function
See SHIFT PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function
See OVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Location/Task/Function Of Command Valve
See LOCATION/TASK/FUNCTION OF COMMAND VALVE
.
Selector Valve, Location/Task
See SELECTOR VALVE, LOCATION/TASK
.
Location/Task/Design/Function Of Oil Pump
See LOCATION/TASK/DESIGN/FUNCTION OF OIL PUMP
.
Shift Valve Pressure, Function
Operation
The shift valve pressure is derived from the regulating valve pressure, regulated at the shift valve pressure
regulating valve and is then present:
1-2 And 4-5 Shift Solenoid Valve (Y3/6Y3)
3-4 Shift Solenoid Valve (Y3/6Y4)
2-3 Shift Solenoid Valve (Y3/6Y5)
Torque Converter Lockup PWM Solenoid Valve (Y3/6Y6)
3-4 And 2-3 Shift Pressure Valve Shift Valve
The shift valve pressure controls the command valves via the upshift/downshift solenoid valves.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function
See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch
See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
Shift Pressure Regulating Valve, Location/Task/Function
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 246 © 2006 Mitchell Repair Information Company, LLC.
Page 1420 of 4133
When the multiple-disc brake (B) is engaged, the working pressure (p-A) is applied to the end face of the shift
valve (29) via the command valve (31). See Fig. 140
. Its shift condition is retained in the shift phase, whilst the
shift element pressure acting on the end face and which is variable during the shift phase is replaced by a
corresponding, constant pressure.
When the multiple-disc clutch (K) is engaged (K) the end face of the shift pressure shift valve (29) is
depressurized during the stationary and shift phases, here the shift condition is also retained during the shift
phase.
Torque Converter Lockup Clutch PWM Solenoid Valve, Design
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 251 © 2006 Mitchell Repair Information Company, LLC.
Page 1422 of 4133
Fig. 141: Torque Converter Lockup Clutch PWM Solenoid Valve
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Structure
The torque converter lockup PWM solenoid valve (Y3/6y6) is sealed off to the valve body of the shift plate (2a)
by an O-ring (34) and a seal (arrow). See Fig. 141
. The contact springs (32) on the PWM converter lockup
solenoid valve (Y3/6y6) engage in a slot in the conductor tracks (33). The force of the contact spring (32)
ensures safe contacts.
Manual Drive Mode Selection, Function (Without Touch Shift)
2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 253 © 2006 Mitchell Repair Information Company, LLC.