1997 MERCEDES-BENZ ML500 catalytic converter

222 OperationEngine compartment
Screw filler cap2 back on filler neck.
More information on engine oil can be
found in the “Technical data” section
(
page 300) and (
page 301).
Transmission fluid level
The transmission fluid level does not need
to be checked. If you notice transmission
fluid loss or gear shifting malfunctions,
have an authorized Mercedes-Benz Light
Truck Center check the automatic trans-
mission.Coolant
The engine coolant is a mixture of water
and anticorrosion / antifreeze. To check
the coolant level, the vehicle must be
parked on level ground and the engine
must be cool.
!Excess oil must be siphoned or drained
off. It could cause damage to the
engine and catalytic converter not
covered by the Mercedes-Benz Limited
Warranty.
Warning!
G
In order to avoid any possibly serious burns:

Use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system,
or if the coolant temperature gauge indi-
cates that the coolant is overheated.


Do not remove pressure cap on coolant
reservoir if engine temperature is above
194°F (90°C). Allow engine to cool
down before removing cap. The coolant
reservoir contains hot fluid and is under
pressure.


Using a rag, slowly open the cap approx-
imately ½ turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.


Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.


281 Practical hints
Jump starting
Jump starting
If the battery is discharged, the engine can
be started with jumper cables and the bat-
tery of another vehicle. Observe the follow-
ing:

Jump starting should only be performed
when the engine and catalytic convert-
er are cold.


Do not start the engine if the battery is
frozen. Let the battery thaw out first.


Only jump start from batteries with the
same voltage rating (12 V). Jump start-
ing with a more powerful battery could
damage the vehicle's electrical system,
which will not be covered by the
Mercedes-Benz Limited Warranty.


Use only jumper cables with sufficient-
cross-section and insulated terminal
clamps.


Always make sure the jumper cables
are not on or near pulleys, fans or other
parts that move when the engine is
started or running.
Warning!
G
Failure to follow these directions will cause
damage to the electronic components, and
can lead to a battery explosion and severe
injury or death.
Never lean over batteries while connecting
or jump starting, you might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water, and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and very explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking, etc.
Attempting to jump start a frozen battery
can result in it exploding, causing personal
injury.
Read all instructions before proceeding.
!Avoid repeated and lengthy starting at-
tempts.
Do not attempt to start the engine us-
ing a battery quick charge unit.
If engine does not run after several un-
successful starting attempts, have it
checked at the nearest authorized
Mercedes-Benz Light Truck Center.
Excessive unburned fuel generated by
repeated failed starting attempts may
damage the catalytic converter and
may present a fire risk.
Make sure the jumper cables do not
have loose or missing insulation.
Make sure the cable clamps do not
touch any other metal part while the
other end is still attached to a battery.

320 IndexBulbs, replacing 266
Additional turn signals 266
Backup lamps 267
Brake lamps 267
Fog lamps 266
Front fog lamp 270
Front lamps 266
High beam 266
High mounted brake lamp 267, 271
License plate lamps 267, 271
Low beam 266
Parking lamps 266, 267, 269
Rear fog lamp 267
Rear fog lamps 270
Rear side marker lamp bulbs 270
Side marker lamps 266, 267, 269
Standing lamps 266, 267
Tail lamp assemblies 267, 270
Turn signal lamps 266, 267, 269C
CAC (Customer Assistance Center) 311
Calibrating compass 188
California
Important notice 11
Calling up
Service indicator 233
CAN system 311
Capacities
Fuels, coolants, lubricants, etc. 300
Cargo area cover blind* 161
Closing 161
Installing 162
Opening 161
Removing 161
Cargo area see Cargo compartment 89
Cargo compartment
Liftgate 89
Lighting 114
Tie-down rings 158Cargo floor plates 162
Installing 163
Removing 162
Storing 162
Cargo tie-down rings 158
Catalytic converter 212
CD-changer* 258
Center console 27
Lower part 28
Upper part 27
Central locking
Automatic 93
From inside 93
Switch 94
Unlocking from inside 93, 94
Central locking switch 94
Certification label 292
Charge indicator lamp 254
Charging
Vehicle battery 279

Fig. 4: Removing & Installing Transmission With Torque Converter
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Remove/Install -
1 - Disconnect ground cable of battery. See DISCONNECT GROUND LEAD FROM BATTERY
.
2 - Remove transfer case. See TRANSFER CASE .
3 - Unbolt oil filler pipe (3) from crankcase. See Fig. 4
.
4 - Remove heat shield (5) and disconnect 13-pin plug connector (2).
5 - Remove locking clips (21) and remove shift.
6 - Unscrew oil drain screw on oil pan (14).
7.1 - Unscrew oil drain screw for torque converter (15).
8.1 - Detach wire for park lock interlock (7) at transmission.
9 - Lambda sensors for primary catalytic converters remove.
10 - Unscrew oil lines (4) to oil cooler from transmission.
11 - Remove cover in oil pan (18) and disconnect torque converter from driven plate at flange.
12 - Unscrew bolts of transmission (19) at crankcase and take out transmission downwards at an angle
using a lifting device. NOTE: Code radio, set clock, normalize power windows and set timer in vehicles
with stationary heater.
NOTE: Adjust shift rod using pliers. See Fig. 10
.
NOTE: If the transmission fluid is burnt or contains wear particles, the oil cooler
lines and oil cooler must be flushed out: Flush oil cooler and oil cooler
lines.
NOTE: Only up to A145272,X708318. For installation and removal, position
selector lever or range selector lever in position "P" and leave in position
"P" when cable/transmission is removed. See REMOVING & INSTALLING
WIRE CABLE/TRANSMISSION FOR PARKING SHIFT LOCK ON
TRANSMISSION.
NOTE: Only up to A145272, X708318.
Upon Installation: Adjust cables for parking shift lock. See ADJUSTING
WIRE CABLES FOR PARKING LOCK INTERLOCK.
NOTE: Upon Installation: Check function of parking shift lock.

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Engine load
Crankshaft position sensor
Camshaft Hall sensor
Coolant temperature sensor
Intake air temperature sensor/charge air.
Coil ignition: The ME control unit interrupts at the point of ignition timing at the ground end the ignition
coil primary circuit of the ignition coil.
ECI ignition system (engine 137): The ME control unit actuates the output stages in the ECI ignition
modules.

The ignition angle can only be checked with the HHT/STAR DIAGNOSIS.
2.Ignition angle adaptation
2.1 Catalytic converter heating-up (warming-up)
The ignition angle is continuously retarded for about 20 seconds in order to more rapidly warm up the catalytic
converter to its operating temperature if:
coolant temperature at start > 15 °C and < 40 °C
Selector lever position P or N
At the same time idle speed is increased by the idle speed control.
2.2 Idle speed
To assist the idle speed control, the ignition angle can be retarded by as much as 36° crank angle or advanced by
as much as 20° crank angle.
Altering the ignition angle provides a more rapid control than altering the position of the throttle valve (idle
speed control).
2.3 Deceleration fuel shutoff
The ignition angle is briefly retarded when combustion is resumed (fuel injectors actuated) in order to prevent a
sudden increase in torque.
2.4 Intake air temperature/coolant temperature
The ignition angle is retarded under load, as a function of the intake air temperature and coolant temperature, in
order to prevent an
y knocking tendency at high intake air and coolant temperatures. The ignition angle is

2001 Mercedes-Benz ML320
1998-2005 ENGINE Electrical System - Engine - 163 Chassis
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"Retarded" if:
Intake air temperature > 35 °C
Coolant temperature > 105 °C
In supercharged engines the charge air temperature is used as information for the ignition timing adjustment in
place of the intake air temperature.

The values of the retardation of the ignition angle of intake air temperature and coolant temperature are added
together.
2.5 Transmission overload protection
In order to protect the shift elements of the automatic transmission during power shifts (1-2-1, 2-3-2) from
excessive thermal stresses, the ignition angle is briefly retarded during the gearshift and the engine torque
reduced as a result. The ME-SFI control units are supplied with a signal for this purpose from the ETC control
unit (N15/3) over the CAN databus.
2.6 ESP/ASR control mode
In order to reduce the engine torque as rapidly as possible in the ESP/ ASR control mode, the ignition angle is
retarded by the throttle valve actuator (opening angle reduced) prior to the control mode being activated. The
information from the ESP/ASR control unit is supplied over the CAN databus to the ME-SFI control unit.
2.7 Anti-knock control (AKC)
If uncontrolled combustion (knocking) occurs at one or several cylinders, the ignition angle at the relevant
cylinder or cylinders is "Retarded".
2.8 Smooth engine running analysis
To restrain the three way catalytic converter from thermal overload through combustion misfiring and in order
to keep the exhaust emission values, the smooth operation of the engine is continuously monitored.
If combustion misfiring is identified at one or several cylinders, the corresponding fuel injection valves are no
longer actuated after a certain number of misfires.
Engine 104, 111, 112, 113, 119, 120: Smooth operation evaluation is performed through the signals of the
crankshaft position sensor.
Engine 137: Identification of combustion misfiring by means of ionic current signal, see ECI ignition system
function.
2.9 Double ignition engine 112,113,137

2001 Mercedes-Benz ML320
1998-2005 ENGINE Electrical System - Engine - 163 Chassis
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different engine loads, e.g. power steering turned to full lock, engaging drive mode, switching on AC
compressor
different mixture, e.g. from activated charcoal canister if purging activated (depending on activated
charcoal charge)
Function
The actuator EFP/TPM/LLR (additional designation: throttle valve actuator) regulates the idling speed by
changing the throttle valve position. It is actuated by the ME-SFI control unit.
The ME-SFI control unit actuates the throttle valve motor (M16/1 m1) in line with the input signals received at
the ME-SFI control unit (N3/10).
Heating speed of the catalytic converter
In order to warm up the catalytic converter more rapidly to operating temperature, engine speed is increased in
the idle speed range to 1100 up to 1500 rpm for about 20 seconds after each starting procedure at coolant
temperatures of < 40 °C. When a Drive position is engaged, engine speed is immediately controlled to a lower
value.
Automatic transmission
When a drive position is engaged, a lower engine speed is controlled in order to reduce the creeping tendency o
f
the vehicle. The information "Drive position engaged/not engaged" is transmitted by the ETC control unit
(N15/3) over the CAN databus to the ME-SFI control unit.
Ignition angle
To assist the idle speed control, the ignition angle can be retarded by as much as 36° crank angle or advanced by
as much as 20° crank angle from the calculated specified value.

The control in the idle speed range by altering the ignition angle reacts more rapidly than altering the position o
f
the throttle valve.
The idling speed can be influenced with HHT or the STAR DIAGNOSIS.
AC compressor
In order to avoid engine speed dropping in the idle speed range when the AC compressor is engaged, the AC
push-button control unit (N19) or automatic air conditioning push-button control unit (N22) supplies a signal to
the ME-SFI control unit (as of approx. 6/96 over CAN) and the opening cross-section of the throttle valve is
enlarged.
When the air conditionin
g unit is switched on and the external temperature exceeds 35° C the idling speed on

2001 Mercedes-Benz ML320
1998-2005 ACCESSORIES & BODY CAB Throttle Control, Speed Control Systems - 163 Chassis
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