check engine MERCEDES-BENZ ML320 1997 Complete Owner's Manual

203 Driving systems
Te ch n ica l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Four-wheel electronic traction system (4-ETS+)
With the key in steering lock position 2, the yellow
4-ETS+ malfunction indicator lamp{ and the 4-ETS+
warning lampv come on and should go out when
the engine is running.
The 4-ETS+ improves vehicle’s ability to utilize available
traction, especially under slippery road conditions. The
brakes are applied to the spinning wheel and power is
transferred to the wheel(s) with traction.
The 4-ETS+ warning lampv, located in the
speedometer dial, starts to flash at any vehicle speed, as
soon as the tires lose traction and the wheels begin to
spin.
Important!
If the 4-ETS+ warning lampv 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.4-ETS+ Control
If the yellow 4-ETS+ malfunction indicator lamp{
comes on while the 4-ETS+ warning lampv flashes,
the electronic traction system is being switched off
temporarily to prevent overheating of the drive wheel
brakes.
If the 4-ETS+ malfunction indicator lamp{ comes on
with the engine running, a malfunction has been
detected.
Have the 4-ETS+ checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
With the ABS malfunctioning, the 4-ETS+ is also
switched off.
Caution!
If the vehicle is towed with the front axle raised (see
towing the vehicle on page 255), or when testing the
parking brake on a brake test dynamometer, the engine
must be shut off (key in steering lock position 0 or 1).
Otherwise, the electronic traction system will
immediately be engaged and will apply the rear wheel
brakes.

204 Driving systems
Te ch n ica l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Note:
In winter operation, the maximum effectiveness of the
electronic traction system is only achieved with
Mercedes-Benz recommended M+S rated radial-ply tires
and / or snow chains.
LOW RANGE – 4-ETS+
During off-road driving a special low range system for
the four wheel electronic traction system (4-ETS+) is
operational with transmission in LOW RANGE mode,
see page 211.
If one or more tires lose traction while driving downhill
(accelerator released), the 4-ETS+ engages and the
warning lampv, located in the speedometer dial,
starts to f lash.Electronic brake proportioning (EBP)
The EBP enhances braking effectiveness by allowing the
rear brakes to supply a greater proportion of the braking
effort without a loss of vehicle stability.
If a warning tone sounds for five seconds and the
symbols É and - are displayed in the instrument
cluster, the system has detected a malfunction and is
switched off. Have the system checked immediately at
an authorized Mercedes-Benz Light Truck Center.
Failure to do so could result in an accident, since the
enhanced braking effect is not available when the
system is switched off.
Note:
When the EBP is switched off, every time the engine is
started, a warning tone will sound for five seconds and
the symbols É and - will light up. In addition,
whenever the brakes are applied at speeds exceeding
25 mph (40 km / h), the warning tone sounds for five
seconds.

206 Driving systems
Te ch n ica l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical 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 lampv 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).

213 What you should know at the gas station
Te ch n ica l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical 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 controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Check regularly and before a long trip 1Engine oil level
See “Checking engine oil level” on page 233 and
“Engine oil level indicator” on page 89.
2Coolant level
See “Coolant level” on page 234.
3Brake fluid
See “Brake fluid” on page 294.
4Windshield 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.

217 Contents - Instrument cluster display
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical 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 .................220Electronic 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 ............................ 222Adjustable 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

218 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical 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 controlsOperation DrivingInstrument
cluster displayPractical 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

222 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
ABS malfunction indicator lamp
The ABS malfunction indicator lamp in the
instrument cluster comes on with the key in
steering lock position 2 and should go out
with the engine running.
When the ABS malfunction indicator lamp in the
instrument cluster comes on while the engine is
running, it indicates that the ABS has detected a
malfunction and has switched off. In this case, the brake
system functions in the usual manner, but without
antilock assistance.
With the ABS malfunctioning, the BAS, ESP and 4-ETS+
are also switched off. Both malfunction indicator lamps
come on with the engine running.
If the charging voltage falls below 10 volts, the
malfunction indicator lamp comes on and the ABS is
switched off. When the voltage is above this value again,
the malfunction indicator lamp should go out and the
ABS is operational.
Have the system checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
See page 201 for notes on antilock brake system (ABS).Adjustable steering wheel – indicator lamp
The indicator lamp in the instrument cluster
comes on with the key in steering lock
position 2 and should go out with the engine
running.
If the indicator lamp does not go out after starting the
engine, the adjustable steering column is not properly
locked.
For locking the adjustable telescoping steering column,
see page 70.
AIRBAG OFF indicator lamp
The indicator lamp will light up for
approximately 6 seconds, extinguish, then
blink once, when you turn the key in
steering lock to position 1 or 2.
The 7 indicator lamp stays lit as long as a
BabySmart
TM compatible child seat is properly installed
on the front passenger seat. It indicates that the front
passenger airbag is switched off.
See page 53 for BabySmart
TM airbag and its deactivation
system.
BabySmart
TM is a trademark of Siemens Automotive Corp.
ABS

224 Malfunction and indicator lamps
Te ch n ica l
data Instruments
and controlsOperation DrivingInstrument
cluster displayPractical hints Car care Index
Low engine oil level warning lamp
With the key in steering lock position 2, the
oil level warning lamp comes on and should
go out when the engine is running.
If the warning lamp does not go out after starting the
engine, or comes on with the engine running and at
operating temperature, the engine oil level has dropped
to approximately the minimum mark on the dipstick.
When this occurs, the warning lamp will first come on
intermittently and then stay on if the oil level drops
further.
If no oil leaks are noted, continue to drive to the nearest
service station where the engine oil should be topped to
the “full” mark on the dipstick with an approved oil.
The low engine oil level warning light should not be
ignored. Extended driving with the light illuminated
could result in serious engine damage that is not
covered by the Mercedes-Benz Limited Warranty.
In addition to the warning lamp, the engine oil level
should be periodically checked with the dipstick or via
the oil level indicator in the odometer display field, for
example during a fuel stop, or before a long trip (see
engine oil level indicator on page 89 and checking
engine oil on page 233).Low engine coolant level warning
When the coolant level warning lamp comes
on while driving, then the coolant level has
dropped below the required level, or the
coolant temperature is in the red zone. If no leaks are
noticeable and the engine temperature does not
increase, continue to drive to the nearest service station
and have coolant added to the coolant system, see
page 234. If the engine temperature reaches the red
zone, move vehicle to an area which is in a safe distance
from the roadway and turn off the engine. Also see
coolant temperature gauge on page 81.
The low engine coolant level warning should not be
ignored. Extended driving with the symbol displayed
may cause serious engine damage not covered by the
Mercedes-Benz Limited Warranty.
In cases of major or frequent minor coolant loss, have
the cooling system checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.
Notes:
Do not drive without coolant in the cooling system. The
engine will overheat causing major engine damage.
Monitor the coolant temperature gauge while driving.