fuel pressure MERCEDES-BENZ ML350 1997 Complete Owner's Manual

227 Operation
Tires and wheels
Life of tire
The service life of a tire is dependent upon
varying factors including but not limited to:

Driving style


Tire pressure


Distance driven
Direction of rotation
Unidirectional tires offer added advantag-
es, such as better hydroplaning perfor-
mance. To benefit, however, you must
ensure that the tires rotate in the direction
specified.
An arrow on the sidewall indicates the in-
tended direction of rotation of the tire.
Checking tire inflation pressure
Correct the tire pressure only when tires
are cold.
Regularly check your tire pressure at inter-
vals of no more than 14 days.
If the tires are warm, you should only cor-
rect the tire pressure if it is too low for cur-
rent operating conditions.
A table on the fuel filler flap lists the spec-
ified tire inflation pressures for warm and
cold tires as well as for various operating
conditions.
!When the wheels are heavily soiled,
e.g. after driving through mud, clean
the inside of the wheels with a jet of
water.Warning!
G
Tires and spare tire should be replaced after
six years, regardless of the remaining tread.
!Keep unmounted tires in a cool, dry
place with as little exposure to light as
possible. Protect tires from contact
with oil, grease and gasoline.
Warning!
G
If the tire pressure drops repeatedly:

Check the tires for punctures from for-
eign objects.


Check to see whether air is leaking from
the valves or from around the rim.

228 OperationTires and wheelsTire pressure changes by approximately
1.5 psi (0.1 bar) per 18°F (10°C) of air
temperature change. Keep this in mind
when checking tire pressure where the
temperature is different from the outside
temperature.
Tire temperature and tire pressure are also
increased while driving, depending on the
driving speed and the tire load.Check the spare tire periodically for condi-
tion and inflation. Spare tire will age and
b e c o m e w o r n o v e r t i m e e v e n i f n e v e r u s e d ,
and thus should be inspected and replaced
when necessary.
Rotating wheels
The wheels can be rotated every 3000 to
6000 miles (5 000 to 10 000 km) or soon-
er if necessary, according to the degree of
tire wear. The same direction of tire rota-
tion must be retained.
Rotate the wheels before the characteris-
tic tire wear pattern becomes visible
(shoulder wear on front wheels and tread
center wear on rear wheels).
Thoroughly clean the inner side of the
wheels after each rotation. Check and en-
sure proper tire inflation pressure.
iThe pressures listed for light loads are
minimum values offering high driving
comfort.
Increased inflation pressures listed for
heavier loads may also be used for light
loads. These higher pressures produce
favorable handling characteristics. The
ride of the vehicle, however, will be
somewhat harder. Never exceed the
max. values or inflate tires below the
min. values listed in the fuel filler flap.
Warning!
G
Follow recommended inflation pressures.
Do not overinflate tires. Overinflated tires
can result in sudden deflation (blowout) be-
cause they are more likely to become punc-
tured or damaged by road debris, potholes,
etc.
Do not underinflate tires. Underinflated tires
wear unevenly, adversely affect handling
and fuel economy, and are more likely to fail
from being overheated.
Do not overload the tires by exceeding the
Gross Vehicle Weight Rating (GVWR) and
the Gross Axle Weight Rating (GAWR) as
indicated on the certification label on the
driver’s door pillar. Overloading the tires can
overheat them, possibly causing a blowout.
Warning!
G
Rotate front and rear wheels only if they are
of the same size,

295 Technical data
Rims and tires
Rims and tires
Use only tires and rims which have been
specifically developed for your vehicle and
tested and approved by Mercedes-Benz.
Other tires and rims can have detrimental
effects, such as

poor handling characteristics


increased noise


increased fuel consumption
Rims and tires
!Moreover, tires and rims not approved
by Mercedes-Benz may, under load, ex-
hibit dimensional variations and differ-
ent tire deformation characteristics
that could cause them to come into
contact with the vehicle body or axle
parts. This may result in damage to the
tires or the vehicle.
iFurther information on tires and rims is
available at any authorized
Mercedes-Benz Light Truck Center. A
tire inflation pressure table is located
on the fuel filler cap of the vehicle. The
tire pressure should be checked regu-
larly and should only be adjusted on
cold tires. Follow tire manufacturer’s
maintenance recommendation includ-
ed with vehicle.
Model
ML 350
ML 500
Rims (light alloy)
8J x 17 H2
81/2J x 17 H2
Wheel offset
2.0in (52mm)
2.0 in (52 mm)
All-season tires (radial-ply tires)
255 / 60 R17 106 H
275 / 55 R17 109 V
Rims* (light alloy)
81/2 J x 17 H2
81/2 J x 17 H2
Wheel offset*
1.85 in (47 mm)
1.85 in (47 mm)
All-season tires (radial-ply tires)*
275 / 55 R17 109 V
275 / 55 R17 109 V

303 Technical data
Fuels, coolants, lubricants etc.
Premium unleaded gasoline
Fuel requirements
Use only premium unleaded meeting
ASTM standard D 439:

The octane number (posted at the
p um p) m us t be 91 mi n. It i s an a vera ge
of both the Research (R) octane num-
ber and the Motor (M) octane number:
(R+M) / 2). This is also known as the
ANTI-KNOCK INDEX.
Unleaded gasoline containing oxygenates
such as ethanol, IPA, IBA and TBA can be
used provided the ratio of any one of these
oxygenates to gasoline does not exceed
10%; MTBE must not exceed 15%.
The ratio of methanol to gasoline must not
exceed 3% plus additional cosolvents.
Using mixtures of ethanol and methanol is
not allowed. Gasohol, which contains 10%
ethanol and 90% unleaded gasoline, can be
used.
These blends must also meet all other fuel
requirements, such as resistance to spark
knock, boiling range, vapor pressure, etc.
Gasoline additives
A major concern among engine manufac-
turers is carbon build-up caused by gaso-
line. Mercedes-Benz recommends only the
use of quality gasoline containing additives
that prevent the build-up of carbon depos-
its.
After an extended period of using fuels
without such additives, carbon deposits
can build up especially on the intake valves
and in the combustion area, leading to en-
gine performance problems such as:

Warm-up hesitation


Unstable idle


Knocking / pinging


Misfire


Power loss
Do not blend other specific fuel additives
with fuel. This only results in unnecessary
costs and may be harmful to the engine
operation.
!To maintain the engine’s durability and
performance, premium unleaded gaso-
l i n e m u s t b e u s e d . I f p r e m i u m u n l e a d e d
is not available and low octane fuel is
used, follow these precautions:

Have the fuel tank only partially
filled with unleaded regular and fill
up with premium unleaded as soon
as possible.


Avoid full throttle driving and abrupt
acceleration.


Do not exceed an engine speed of
3000 rpm if the vehicle is loaded
with a light load such as two per-
sons and no luggage.


Do not exceed
2/3 of maximum ac-
celerator pedal position if the vehi-
cle is fully loaded or operating in
mountainous terrain.

and skin caused
by contact with
fuel
1
Remove key
from electronic
ignition switchOnly on vehicles with electronic ignition switch.
Vehicles with Keyless Go code 889: Switch off engine, remove Keyless
Go-Cards out of vehicle and store outside of the sender range.

2
Remove cover
on front side of
engine
Model 129, 211, 215, 220, 230 only
3.1
Remove engine
cover with
integrated air
filterExcept model 171.473, 203.076 /276, , 209.376 /476 from 24.4.04
The air filter is integrated in the engine cover. Remove engine cover or air
filter by pulling it vertically up and off the cylinder head covers.

3.2Remove air
filter housingModel 171.473
Model 203.076/ 276
Model 209.376/ 476 as of 24.4.04AR09.10-
P-1150AC
4
Remove hot
film mass air
flow sensor
with air intake
pipe
Engine 112.910/ 920/ 921/940/ 941/ 942/ 970
Engine 113.940AR07.07-
P-1454A
Engine 112.922 /944 /972 /973 /975
Engine 113.941/ 948/ 960/ 961/ 963/ 966AR07.07-
P-1454AA
Engine 112.912 /913 /916 /917 /946 /947 /949 /954 /953 /955
Engine 113.968 /967 /969 /987 /988 /989AR07.07-
P-1454SV
Engine 112.923 /943
Engine 113.943 /944 /980 /984AR07.07-
P-1454AG
Engine 113.942 /965/981
AR07.07-
P-
1454MV
5
Disconnect
lead line (17/2)
at the fuel
distributor
Release fuel pressure via service valve and collect fuel.

*BA07.52
P-1001-
01A
Fig. 12
6
Removing fuel
rail with
injection valvesEngine 112.910 /920 /921 /923 /940 /941 /942 /943 /970
Engine 113.940 /942 /943 /944 /961 /965 /980 /981 /984AR07.03-
P-1451A

Engine
112.912/913 /916 /917 /922 /944 /946 /947 /949 /953 /954 /955 /972 /973 /975
Engine 113.941 /948 /960 /963 /966 /967 /968 /969 /987 /988 /989AR07.03-
P-1451AA
Unscrew

2001 Mercedes-Benz ML320
1998-2005 ENGINE Air Intake, Turbo Charging - 163 Chassis
me
Saturday, October 02, 2010 3:16:57 PMPage 11 © 2006 Mitchell Repair Information Company, LLC.

Shift-Lock, Function

See SHIFT
-LOCK FUNCTION.
Park Pawl Interlock, Function

See PARK PAWL INTERLOCK, FUNCTION
.
Steering Lock Interlock, Function

See STEERING LOCK INTERLOCK, FUNCTION
.
Survey Of System Components, Automatic Transmission, Location/Task/Design/Function

See SURVEY OF SYSTEM COMPONENTS, AUTOMATIC TRANSMISSION,
LOCATION/TASK/DESIGN/FUNCTION.
Automatic Transmission, Function
Automatic transmission 722.6 is an electronically controlled 5-speed transmission with a lockup clutch in the
torque converter.
The ratios for the gear stages are achieved by three planetary gear sets. The 5th gear is designed with a step-up
ratio as an overdrive.
Shifting is initiated electronically. The gears are shifted by the corresponding combination of three
hydraulically actuated multi-disc clutches and two mechanical freewheels.
Basically automatic transmission 722.6 with electronic control offers the following advantages:
Reduced Fuel Consumption
Improved Shift Comfort
More Favorable Gear Steps As A Result Of 5 Gears
Enhanced Life And Reliability
Reduced Servicing Costs
The electrohydraulic control unit is bolted onto the bottom of the transmission housing. The end of the
transmission is formed by an oil pan made of sheet steel.
The oil pressure for the converter lockup clutch and center multiple-disc clutch is supplied via holes in the input
shaft. The oil pressure to the rear mulitiple-disc clutch is routed through the output shaft. The lubricating oil is
supplied and distributed by additional bore holes in both shafts. All bearing points of the gear sets as well as
freewheels and shift elements are supplied with lubricatin
g oil. NOTE: Transmission Without Touch Shift 722.6 In Model 163.

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:25 PMPage 32 © 2006 Mitchell Repair Information Company, LLC.

Fig. 106: Torque Converter Lockup Clutch, Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Operation
When actuated by the ETC control module (N15/3), oil pressure controlled by the torque converter lockup
PWM solenoid Valve (Y3/6y6) is directed through the input shaft (1) to the pressure chamber behind the piston
(16d). See Fig. 106
. The piston presses the clutch pack (16c) together and allows torque to be transferred
directly between the impeller (P) and turbine wheel (T). The torque converter lockup clutch is activated in 5th,
4th and 3rd gears in relation to the engine speed and engine load.
AUTOMATIC TRANSMISSION, FUNCTION
Transmission without touch shift. 722.6 in MODEL 163, 170, 202, 208, 210.
Transmission 722.6 in MODEL 129, 140.
Automatic transmission 722.6 is an electronically controlled 5-speed transmission with a lockup clutch in the
torque converter.
The ratios for the gear stages are achieved by three planetary gear sets. The 5th gear is designed with a step-up
ratio as an overdrive.
Shifting is initiated electronically. The gears are shifted by the corresponding combination of three
hydraulically actuated multi-plate brakes, three hydraulically actuated multi-disc clutches and two mechanical
freewheels.
Basically automatic transmission 722.6 with electronic control offers the following advantages:
Reduced fuel consumption
Improved shift comfort
More favorable gear steps as a result of 5 gears
Enhanced life and reliability
Reduced servicing costs
The electrohydraulic control unit is bolted onto the bottom of the transmission housing. The end of the
transmission is formed by an oil pan made of sheet steel.
The oil pressure for the converter lockup clutch and center multiple disc clutch is supplied via holes in the input
shaft. The oil pressure to the rear multiple-disc clutch is routed through the output shaft. The lubricating oil is
supplied and distributed by additional bore holes in both shafts. All bearing points of the gear sets as well as
freewheels and shift elements are supplied with lubricating oil.
The parking lock gear and drive flange are connected to the output shaft by gearing.
Freewheels F1 and F2 optimize shiftin
g. The front freewheel (F1) rests against the stator shaft extension on the

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:28 PMPage 183 © 2006 Mitchell Repair Information Company, LLC.

Fig. 108: Selector Lever Positions
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
AUTOMATIC TRANSMISSION, FUNCTION
Transmission With Touch Shift 722.6 In Model 163
Transmission 722.6 is an electronically controlled 5-speed transmission with a lockup clutch in the torque
converter.
The ratios for the gear stages are achieved by 3 planetary gearsets. The 5th gear is designed as a low-rev gear
with an overdrive ratio.
Shifting is initiated electronically. The gears are shifted by the corresponding combination of 3 hydraulically
actuated multi-disk brakes, 3 hydraulically actuated multi-disk clutches and 2 mechanical freewheels.
The oil pump as well as the external plate carrier of the front multi-disk brake are bolted to the torque converter
housing.
The mechanical part of the transmission 722.6 consists of a drive shaft, output shaft, a sun gear shaft and 3
planetary sets which are coupled to each other.
The electrohydraulic control unit is screwed onto the transmission housing from below. The end of the
transmission if formed by an oil pan made of sheet steel.
The oil pressure of the torque converter lockup clutch and center multi-disk clutch is supplied via bore holes in
the drive shaft. The oil pressure to the rear multi-disk clutch is supplied via the output shaft. The lubricating oil
is supplied and distributed by additional bore holes in both shafts. Oil is supplied to all bearing points of the
gearsets as well as to the freewheels and shifting elements.
The parking lock gear and drive flange are connected to the output shaft by gearing.
Basically transmission 722.6 with electronic control offers the following advantages:
Reduced fuel consumption.
Greater ease of shifting.
Favorable spacing by 5 gears.
Long service life and high reliability.
Low maintenance costs.
The torque converter housing and transmission housing consist of a light-metal alloy. Both housings are bolted
together and are centered via the external plate carrier of the multi-disk brake at the front. A coated intermediate
panel seals the two components.
Freewheels F1 and F2 optimize shifting. The front freewheel F1 is supported on the extension of the stator shaft
on the transmission end and connects in the lockin
g direction the sun gear of the front planetary gearset with the

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:28 PMPage 189 © 2006 Mitchell Repair Information Company, LLC.

The aim of using the torque converter lockup clutch is to reduce the fuel consumption and exhaust gas
emissions of the vehicle by reducing torque converter slip. See Fig. 159
. This stands in contradiction to the ride
comfort demands made on the drive train with regard to its vibration behavior. The task of the electronic
transmission control is therefore to close the clutch in all driving situations relevant to fuel consumption, if
possible, and ensure that the engine vibrations are isolated from the drive train.
The characteristic curves shown in the diagram illustrate the different operating states of the torque converter
lockup clutch in relation to the accelerator pedal position and transmission output speed, plotted for one
transmission gear.
In addition to the evaluation of these characteristics, the status of the torque converter lockup clutch is also
determined by other variables.
Variables influencing the states of the torque converter lockup clutch:
Accelerator Pedal Movement
Uphill And Down Hill Gradients
Transmission Shift Functions
ATF Temperature
Durability Requirements
Load Condition
Engine Control Influences
Torque Converter Lockup Clutch Control Pressure, Function

See TORQUE CONVERTER LOCKUP CLUTCH CONTROL PRESSURE, FUNCTION
.
Torque Converter Lockup Clutch Control Pressure, Function
Apart from extreme states of open or closed, it is possible to operate the torque converter lockup clutch with
preset slip speeds. To enable this variable control pressure must be applied to the torque converter lockup clutch
regulating valve.
The torque converter lockup clutch control pressure is adapted to each operating state via the pulse-width
modulated torque converter lockup solenoid valve (Y3/6y6) which is actuated by the ETC control unit (N15/3).
Torque Converter Lockup Clutch PWM Solenoid Valve, Location/Task/Design/Function

See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
Torque Converter Lockup Clutch, Location/Task/Design/Function

See TORQUE CONVERTER LOCK
-UP CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.
Torque Converter Lockup Clutch Regulating Valve, Location/Task/Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:29 PMPage 283 © 2006 Mitchell Repair Information Company, LLC.

The aim of using the torque converter lockup clutch is to reduce the fuel consumption and exhaust gas
emissions of the vehicle by reducing torque converter slip. See Fig. 165
. This stands in contradiction to the ride
comfort demands made on the drive train with regard to its vibration behavior. The task of the electronic
transmission control is therefore to close to the clutch in all driving situations relevant to fuel consumption, if
possible, and ensure that the engine vibrations are isolated from the drive train.
The characteristic curves shown in the diagram illustrate the different operating states of the torque converter
lockup clutch in relation to the accelerator pedal position and transmission output speed, plotted for one
transmission gear.
In addition to the evaluation of these characteristics, the status of the torque converter lockup clutch is also
determined by other variables.
Variables influencing the states of the torque converter lockup clutch:
Accelerator Pedal Movement
Uphill And Down Hill Gradients
Transmission Shift Functions
ATF Temperature
Durability Requirements
Load Condition
Engine Control Influences
Torque Converter Lockup Clutch Control Pressure, Function

See TORQUE CONVERTER LOCKUP CLUTCH CONTROL PRESSURE, FUNCTION
.
REMOVE/INSTALL TRANSFER CASE
Remove/Install

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:30 PMPage 296 © 2006 Mitchell Repair Information Company, LLC.