2002 MERCEDES-BENZ ML320 Light switch

221 Driving systems
Te ch n i c a 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 traction control engages at vehicle speeds up to
approx. 24 mph (40 km / h), and switches off at
50 mph (80 km / h).
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 277), 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.

222 Driving systems
Te ch n i c a 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 229.
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 flash.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.

224 Driving systems
Te ch n i c a 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.
Turn steering wheel completely to the left and then to
the right. The BAS / ESP malfunction indicator lamp
should go out.
If battery voltage drops below 10 volts, the indicator
lamp comes on and the brake assist system (BAS) is
deactivated. If the battery voltage rises and exceeds
10 volts, the BAS / ESP malfunction indicator lamp goes
out, and brake assist system (BAS) is functional again.
After driving off the BAS / ESP malfunction indicator
lamp should go out after approximately 110 - 220 yd
(100 - 200 m).

228 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
Switching on:
1. Stop the vehicle.
2. Move transmission selector lever to position “N”.
3. Push top end of switch. The LOW RANGE indicator
lamp in the instrument cluster blinks three times
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.Switching off:
1. S to p t h e ve 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 three times during
the changeover.
Once the changeover is complete, the indicator lamp in
the instrument cluster goes out. Use the gear selector
lever normally.
Note:
If the indicator lamp blinks fast, one or more switching
conditions were not observed, or the LOW RANGE mode
is defective.

229 Driving systems
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index Important!
During off-road driving a special low range system for
antilock brake system (ABS) and four-wheel electronic
traction system (4-ETS+) are operational with
transmission in the LOW RANGE mode.
In the low range mode the electronic stability program
(ESP) operates in a traction improving fashion
specifically adapted for off-road driving. At speeds
below 27 mph (45 km / h) the ESP assists in over- /
understeering, thus improving vehicle tracking.
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 flash.
When applying the service brakes at speeds below
approximately 18 mph (30 km / h), the front wheels are
locked cyclically to shorten the braking distance (dig in
effect). This affects steering the vehicle.Notes:
Driving off or driving up to 3 mph (5 km / h) with the
service brakes applied lightly (to reduce drive wheel
spin), the 4-ETS+ remains engaged. Driving with the
service brakes applied lightly at vehicles speeds above
3 mph (5 km / h), the 4-ETS+ will not engage.
If the indicator lamp blinks fast, one or more switching
conditions were not observed, or the LOW RANGE mode
is defective.
In the case of a defective in the LOW RANGE mode the
transmission shifts in the usual manner. It is not
possible to switch on the LOW RANGE mode.
Have the transmission checked at your authorized
Mercedes-Benz Light Truck Center as soon as possible.

234 Parking system
Te ch n i c a l
data Instruments
and controlsOperationDrivingInstrument
cluster displayPractical hints Car care Index
All yellow and one or both red segments light up.
Additionally, there is an acoustic warning lasting
approximately 3 seconds.
The obstacle may not be recognized if outside the
shaded sensor field, and no longer be indicated when
approaching it any closer (warning indicators go out).
Parktronic malfunction
All red segments of the warning indicators light up, and
a warning sounds for 3 seconds, if Parktronic does not
function properly.
A dirty sensor or other ultrasonic signals could be the
reason. See page 301 for instructions on cleaning the
sensors in the bumpers.
After cleaning the sensors, turn electronic key in
steering lock to position 2. If a malfunction continues to
be displayed, have the system checked at your
authorized Mercedes-Benz Center.Parktronic switch
The switch is located on the center console.
1Parktronic switched off
2Parktronic switched on
3Indicator lamp – comes on when Parktronic is
switched off
The parktronic system is switched on again when
turning the electronic key in steering lock position 2.3

238 Check regulary and before a long trip
Te ch n i c a 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 255 and
“Engine oil level indicator” on page 96.
2Coolant level
See “Coolant level” on page 256.
3Brake fluid
See “Brake fluid” on page 316.
4Windshield washer system/
Headlamp cleaning system/
Rear window washer system
For refilling reservoir see page 258.
Opening hood, see page 253.
Vehicle lighting: Check function and cleanliness. For
replacement of light bulbs, see “Exterior lamps” on
page 282.
Exterior lamp switch, see page 97.

240 Malfunction and indicator lamps
Te ch n i c a 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 242 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