2006 MERCEDES-BENZ ML500 check engine light

385 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
?
(USA only)
±
(Canada only)
The yellow engine malfunction
indicator lamp comes on while
driving.
There is a malfunction in:

The fuel management
system


The ignition system


The emission control
system


Systems which affect
emissions
Such malfunctions may result
in excessive emissions values
and may switch the engine to
its limp-home (emergency op-
eration) mode (
page 192).

Have the vehicle checked as soon as
possible by an authorized
Mercedes-Benz Light Truck Center.
An on-board diagnostic connector is
used by the service station to link the
vehicle to the shop diagnostics
system. It allows the accurate identifi-
cation of system malfunctions through
the readout of diagnostic trouble
codes. It is located in the front left area
of the footwell next to the parking
brake pedal.

386 Practical hintsWhat to do if …Problem
Possible cause
Suggested solution
?
(USA only)
±
(Canada only)
The yellow engine malfunction
indicator lamp comes on while
driving.
A loss of pressure has been
detected in the fuel system.
The fuel cap may not be closed
properly or the fuel system
may be leaky.

Check the fuel cap (
page 323).
If it is not closed properly:

Close the fuel cap.
If it is closed properly:

Have the fuel system checked by an
authorized Mercedes-Benz Light Truck
Center.
Your fuel tank is empty.

After refueling start, turn off and
restart the engine three or four times in
succession.
The limp-home mode is canceled. You do
not need to have your vehicle checked.

387 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
v
The yellow ESP
® warning lamp
comes on while the engine is
running.
The ESP
® is deactivated.
Risk of accident!
Adapt your speed and driving to the prevail-
ing road, weather, and traffic conditions.

Switch the ESP
® back on (
page 98).
If the ESP
® cannot be switched back on,
have the system checked at an autho-
rized Mercedes-Benz Light Truck Center
as soon as possible.
v
The yellow ESP
® warning lamp
flashes while driving.
The ESP
® or traction control has come into
operation because of detected traction loss
of at least one tire.

When driving off, apply as little throt-
tle as possible.

While driving, ease up on the acceler-
ator.

Adapt your speed and driving to the
prevailing road and weather condi-
tions.

Do not deactivate the ESP
®.
Exceptions: (
page 97).
Failure to follow these instructions in-
creases the risk of an accident.

407 Practical hints
What to do if …
Symbol messagesDisplay symbol
Display messages
Possible cause
Possible solution
#
Undervoltage
Switch off consumers
The battery has insufficient volt-
age.

Turn off unnecessary electrical
consumers.
malfunction
Visit workshop
The battery was charged with a
battery charger or jump started.

Have the battery checked at a service
station.
Battery/Alternator
Stop vehicle
The battery is no longer charg-
ing.
Possible causes:

alternator malfunctioning


broken poly-V-belt
Do not forget that the brake sys-
tem requires electrical energy
and may be operating with re-
stricted capability. Considerably
greater brake pedal force is
required and the stopping dis-
tance is increased.

Stop immediately and check the
poly-V-belt.
If it is broken:

Do not continue to drive. Otherwise the
engine will overheat due to an inoperative
water pump which may result in damage
to the engine. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:

Drive immediately to the nearest autho-
rized Mercedes-Benz Light Truck Center.
Adjust driving to be consistent with re-
duced braking responsiveness.

409 Practical hints
What to do if …
Display symbol
Display message
Possible cause
Possible solution
;
(USA only)
!
(Canada only)
Release
parking brake
You are driving with the parking
brake set.

Release the parking brake (
page 52).
Brake fluid too low
Visit workshop
There is insufficient brake fluid
in the reservoir.

Risk of accident! Stop the vehicle and no-
tify an authorized Mercedes-Benz Light
Truck Center. Do not add brake fluid! This
will not solve the problem.
Warning!
G
Driving with the message
Brake fluid
too low Visit workshop
displayed can
result in an accident. Have your brake
system checked immediately. Do not 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.!If you find that the brake fluid in the
brake fluid reservoir has fallen to the
minimum mark or below, have the
brake system checked for brake pad
thickness and leaks.
!Brake pad thickness must be visually
inspected by a qualified technician at
the intervals specified in the
Maintenance Booklet.

410 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
?
(USA only)
±
(Canada only)
Visit workshop
There may be a malfunction in
the:

Fuel injection system


Ignition system


Exhaust system


Fuel system

Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.
B
Coolant
Check level
The coolant level is too low.

Add coolant (
page 332).

If you have to add coolant frequently,
have the cooling system checked by an
authorized Mercedes-Benz Light Truck
Center.
Warning!
G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You can be seriously burned.
!Do not ignore the low engine coolant
level warning. Extended driving with
the message and symbol displayed
may cause serious engine damage not
covered by the Mercedes-Benz Limited
Warranty.
Do not drive without sufficient amount
of coolant in the cooling system. The
engine will overheat causing major en-
gine damage.

412 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
Ï
Coolant
Stop, engine off
The poly-V-belt could be broken.

Stop the vehicle and immediately turn off
the engine.

Check the poly-V-belt.
If it is broken:

Do not continue to drive. Otherwise the
engine will overheat due to an inoperative
water pump which may result in damage
to the engine. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:

Do not continue to drive the vehicle with
this message displayed. Doing so could
result in serious engine damage that is
not covered by the Mercedes-Benz Limit-
ed Warranty.

Drive immediately to the nearest autho-
rized Mercedes-Benz Light Truck Center.
Coolant
Visit workshop
The cooling fan for the coolant is
malfunctioning.

Observe the coolant temperature gauge
in the instrument cluster.

Have the fan replaced as soon as possi-
ble.

415 Practical hints
What to do if …
When the
Add 1 qt. engine oil when
next refueling
(Canada:
1 liter
) mes-
sage appears while the engine is running
and at operating temperature, the engine
oil level has dropped to approximately the
minimum level.
When this occurs, the warning will first
come on intermittently and then stay on if
the oil level drops further.Visually check for oil leaks. If no obvious oil
leaks are noted, drive to the nearest
service station where the engine oil should
be topped to the required level with an ap-
proved oil specified in the Factory
Approved Service Products pamphlet.
Display symbol
Display messages
Possible cause
Possible solution
N
Engine oil level
Visit workshop
The engine oil has dropped to a
critical level.

Check the engine oil level (
page 328)
(ML 500 only), or (
page 330) (ML 350
only) and add oil as required
(
page 331).

If you must add engine oil frequently, have
the engine checked for possible leaks.
Oil sensor malfunction
Visit workshop
The measuring system is mal-
functioning.

Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.
!The engine oil level warnings should
not be ignored. Extended driving with
the symbol displayed could result in
serious engine damage that is not
covered by the Mercedes-Benz Limited
Warranty.