engine MERCEDES-BENZ ML320 1997 Complete Repair Manual

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Driving systems
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Electronic stability program (ESP)
The ESP enhances directional control and reduces
driving wheel spin of the vehicle under various driving
conditions.
Over-/understeering of the vehicle is counteracted by
applying brakes to the appropriate wheel to create a
countervailing vehicle movement. Engine torque is also
limited. The ESP warning lamp, located in the
speedometer dial, starts to flash when ESP is in
operation. Important!
If the ESP warning lamp v flashes:
• During take-off apply as little throttle as possible.
• While driving ease up on the accelerator.
• Adapt your speed and driving to the prevailing road
conditions.
• Do not switch off the ESP.
Caution!
If the vehicle is towed with the front axle raised (see
towing the vehicle on page 255), the engine must be
shut off (key in steering lock position 0 or 1). Otherwise,
the ESP will immediately be engaged and will apply the
rear wheel brakes.
Notes:
The malfunction indicator lamp for the ESP is combined
with that of the BAS.
The yellow BAS / ESP malfunction indicator lamp ¿
in the instrument cluster and the yellow ESP warning
lamp v in the speedometer dial come on with the
key in steering lock position 2. They should go out with
the engine running.
Wa r n i n g !
ESP cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase the
traction afforded. The ESP cannot prevent
accidents, including those resulting from excessive
speed in turns, or aquaplaning. Only a safe,
attentive, and skillful driver can prevent accidents.
The capabilities of an ESP equipped vehicle must
never be exploited in a reckless or dangerous
manner which could jeopardize the user’s safety or
the safety of others.

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Driving systems
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
If the BAS / ESP malfunction indicator lamp ¿ comes
on continuously with the engine running, a malfunction
has been detected in either system. Only partial engine
output will be available.
If the BAS malfunctions, the brake system functions in
the usual manner, but without BAS.
If the BAS / ESP malfunction indicator lamp stays
illuminated, have the BAS or ESP checked at your
authorized Mercedes-Benz Light Truck Center as soon
as possible.
With the ABS malfunctioning, the ESP is also switched
off.
Driving the vehicle with varied size tires will cause the
wheels to rotate at different speeds, therefore the ESP
may activate (yellow ESP warning lamp v in
speedometer dial comes on). For this reason, all wheels,
including the spare wheel, must have the same tire
outside diameter. When testing the parking brake on a brake test
dynamometer, the engine must be shut off. Otherwise,
the ESP will immediately be engaged and will apply the
rear wheel brakes.
In winter operation, the maximum effectiveness of the
ESP is only achieved with Mercedes-Benz recommended
M+S rated radial-ply tires and / or snow chains.
Synchronizing ESP
If the power supply was interrupted (battery
disconnected or empty), the BAS / ESP malfunction
indicator lamp may be illuminated with the engine
running.
After driving off the BAS / ESP malfunction indicator
lamp should go out after approximately 110 - 220 yd
(100 - 200 m).

207
Driving systems
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
ESP control switch
ESP control switch located in center console.
To switch ESP off, press upper half of switch.
ESP warning lamp v, located in speedometer dial,
comes on.
To switch ESP on again, press lower half of switch.
ESP warning lamp v, located in speedometer dial,
goes out. To improve the vehicle’s traction when driving with
snow chains, or starting off in deep snow, sand or gravel,
or off-road driving, switch off ESP by pressing the upper
half of the ESP switch. The ESP warning lamp v,
located in the speedometer dial, is continuously
illuminated.
With the ESP system switched off, the engine torque
reduction feature is cancelled. Therefore, the enhanced
vehicle stability offered by ESP is unavailable.
Adapt your speed and driving to the prevailing road
conditions.
A portion of the ESP system remains active, even with
the switch in the OFF position.
P54.25-2037-26
Wa r n i n g !
ESP should not be switched off during normal
driving other than in circumstances described
above. Disabling of the system will reduce vehicle
stability in standard driving maneuvers.
When the ESP warning lamp is illuminated
continuously, the ESP is switched off.
Adapt your speed and driving to the prevailing road
conditions.

209
Driving systems
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Transmission control – LOW RANGE mode
The switch is located in the instrument panel.
Important!
When switching to or from the LOW RANGE mode,
observe the following:
• The vehicle must be at a complete standstill.
• The engine speed must not exceed 1500 rpm. Failure to do so may result in transmission / engine
damage not covered by the Mercedes-Benz Limited
Warranty
The LOW RANGE mode should be switched on:
• during off-road driving,
• when crossing waters.
For additional practical hints refer to off-road driving
on page 183.
Switching on: 1. Sto p t h e v e h i c l e .
2. Move transmission selector lever to position “N”.
3. Push top end of switch. The LOW RANGE indicator lamp in the instrument cluster blinks slowly during
the changeover.
Once the changeover is complete, the indicator lamp in
the instrument cluster lights up continuously.
Note:
If the indicator lamp blinks fast, one or more switching
conditions were not observed, or the LOW RANGE mode
is defective.

213
What you should know at the gas station
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Leaving the engine running and the fuel cap open can
cause the “CHECK ENGINE” lamp to illuminate.
Fuel tank capacity approximately 19.0 US gal (72.0 l).
This includes approximately 3.2 US gal (12.0 l) reserve.
Use premium unleaded gasoline: Posted Octane
Index 91 (Average of 96 RON / 86 MON).
•Engine oil Engine oil level check, see page 89 and page 233.
Fill quantity between upper and lower dipstick
marking level: 2.1 US qt (2.0 l).
Recommended engine oils, see Approved Service
Products sheet. • Coolant
For normal replenishing, use water (potable water
quality).
For further information (e.g. anticorrosion/
antifreeze), see page 292.
• Spark plugs Approved spark plugs, see page 290.
• Tire pressure For tire pressure, refer to tire pressure label inside
the fuel filler flap. See page 250 for further details.
• Air conditioner R-134a refrigerant and special PAG lubricant, see
page 294.
Wa r n i n g !
Overfilling of fuel tank may result in creating
pressure in the system which could cause a gas
discharge such as the gas spraying back out upon
removing the filler nozzle which could cause
personal injury.

215
Check regulary and before a long trip
Te ch n ica l
data
Instruments
and controls Operation
Driving Instrument
cluster display Practical hints Car care Index
Check regularly and before a long trip 1
Engine oil level
See “Checking engine oil level” on page 233 and
“Engine oil level indicator” on page 89.
2 Coolant level
See “Coolant level” on page 234.
3 Brake fluid
See “Brake fluid” on page 294.
4 Windshield washer system/
Headlamp cleaning system/
Rear window washer system
For refilling reservoir see page 236.
Opening hood, see page 231.
Ve h i c l e l i g h t i n g : Check function and cleanliness. For
replacement of light bulbs, see “Exterior lamps” on
page 260.
Exterior lamp switch, see page 90.

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Contents - Instrument cluster display
Te ch n ica l
data
Instruments
and controls Operation Driving
Instrument
cluster display Practical hints Car care Index
Instrument cluster displayMalfunction and indicator
lamps in the
instrument cluster .................... 218
On-board diagnostic system –
Check engine malfunction
indicator lamp ............................. 218
Brake warning lamp .................. 219
Supplemental restraint system
(SRS) indicator lamp .................. 219
Fuel reserve warning .................220 Electronic stability
program (ESP) / Electronic
traction system (ETS) –
warning lamp ............................. 221
BAS/ESP malfunction
indicator lamp ............................ 221
4-ETS malfunction
indicator lamp ............................ 221
LOW RANGE
indicator lamp ............................ 221
ABS malfunction
indicator lamp ............................ 222 Adjustable steering wheel –
indicator lamp .............................222
AIRBAG OFF
indicator lamp .............................222
Seat belt warning lamp .............223
Charge indicator lamp ...............223
Low engine oil level
warning lamp ..............................224
Low engine coolant
level warning ..............................224
Brake pad wear
indicator lamp .............................225
FSS indicator ...............................225

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Malfunction and indicator lamps
Te ch n ica l
data
Instruments
and controls Operation Driving
Instrument
cluster display Practical hints Car care Index
Malfunction and indicator lamps
in the instrument cluster
General information:
If a bulb in the instrument cluster fails to light up
during the bulb self-check when turning the key in
steering lock to position 2, have it checked and replaced
if necessary.
On-board diagnostic system
Check engine malfunction indicator lamp
Engine malfunction indicator lamp. If the
“CHECK ENGINE” malfunction indicator
lamp comes on when the engine is running,
it indicates a malfunction of the fuel management
system, emission control system, systems which impact
emissions, or the fuel cap is not closed tight (check the
fuel cap). If the “CHECK ENGINE” lamp is illuminated
continuously and the vehicle is driving normally, you
may still drive the vehicle, however, in all cases, we
recommend that you have the system checked at your
authorized Mercedes-Benz Light Truck Center as soon
as possible.
If the “CHECK ENGINE” lamp comes on continuously
and / or the vehicle is not driving normally (e.g.
malfunction of the fuel management system or running out of fuel), serious damage can occur to the emission
system. Please contact your authorized Mercedes-Benz
Light Truck Center immediately.
The Sequential Multiport Fuel Injection (SFI) control
module monitors emission control components that
either provide input signals to or receive output signals
from the control module. Malfunctions resulting from
interruptions or failure of any of these components are
indicated by the “CHECK ENGINE” malfunction
indicator lamp in the instrument cluster and are
simultaneously stored in the SFI control module.
If the “CHECK ENGINE” malfunction indicator lamp
comes on, have the system checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
With some exceptions, the control module switches off
the “CHECK ENGINE” malfunction indicator lamp if the
condition, causing the lamp to come on, no longer exists
during three consecutive cycles. See also page 220 for
fuel cap placement warning.
An on-board diagnostic connector is located in the
passenger compartment near to the parking brake
pedal, allowing the accurate identification of system
malfunctions through the readout of diagnostic trouble
codes.
CHECK
ENGINE

219
Malfunction and indicator lamps
Te ch n ica l
data
Instruments
and controls Operation Driving
Instrument
cluster display Practical hints Car care Index
Brake warning lamp
When the brake warning lamp appears
while the engine is running, this means:
• there is insufficient brake fluid in the reservoir
(engine running and parking brake released), or
• the parking brake is set (engine running)
• the electronic brake proportioning (EBP) system is
malfunctioning.
Note:
If you find that the minimum mark on the brake fluid
reservoir is reached, have the brake system checked for
brake pad thickness and leaks. Supplemental restraint system (SRS) indicator lamp
The operational readiness of the airbag
system is verified by the indicator lamp
“SRS” in the instrument cluster when
turning the key in steering lock to position 1 or 2. If no
fault is detected, the lamp will go out after
approximately 5 seconds; after the lamp goes out, the
system continues to monitor the components and
circuitry of the airbag system and will indicate a
malfunction by coming on again.
See page 56 for notes on airbags, page 55 for belt
tensioners, and page 65 for infant and child seat
restraints.
Wa r n i n g !
Driving with the brake warning lamp illuminated
can result in an accident. Have your brake system
checked immediately if the brake warning lamp
stays on. Don’t add brake fluid before checking the
brake system. Overfilling the brake fluid reservoir
can result in spilling brake fluid on hot engine
parts and the brake fluid catching fire. You can be
seriously burned.BRAKE
Wa r n i n g !
In the event a malfunction of the “SRS” is indicated
as outlined above, the “SRS” may not be
operational. For your safety, we strongly
recommend that you visit an authorized
Mercedes-Benz Light Truck Center immediately to
have the system checked; otherwise the “SRS” may
not be activated when needed in an accident, which
could result in serious or fatal injury, or it might
deploy unexpectedly and unnecessarily which
could also result in injury.SRS

220
Malfunction and indicator lamps
Te ch n ica l
data
Instruments
and controls Operation Driving
Instrument
cluster display Practical hints Car care Index
Fuel reserve warning When the warning lamp (1) comes on after starting the
engine, or if it comes on while driving, it indicates that
the fuel level is down to the reserve quantity of
approximately 3.2 gal (12 liters).
See page 212 for notes on refueling the vehicle.