|
No.
|
TECH 1 Display
|
Conditions for
Checking
|
Nominal Value
|
Trouble Codes
|
Terminal
|
|
|
08
|
IDLE AIR CONTROL
|
Engine running at idle speed, operating temperature
Note:
If 8 steps are not attained or 26 steps are
exceeded (at idle speed without load) for longer than 10 s, the control
unit resets the stepper motor after ignition OFF. After an interval of
5 s, re - start the engine. If, after this procedure, the number of
steps is less than 8 or greater than 35, initiate trouble - shooting.
If the number of steps continues to border around 26 (24 to
28), ensure by switching on load (lamp, rear screen heating, selector lever
in position "D") that 26 steps are exceeded for longer than
10 s. Then proceed as described above.
|
8 to 26 steps
|
35
|
C 5, C 6,
C 8, C 9/D 1/
|
|
|
Trouble - shooting:
|
Nominal Value:
|
Cause of Fault:
(If nominal value is not attained)
|
|
|
· Slowly
increase speed up to 4000 rpm by actuating the accelerator cable, hold
briefly and let it sink to idle speed once again.
· Wait
approx. 5 s.
Vehicle with MT
|
|
· Carry
out test step 04.
|
|
|
Vehicle with AT
Engage parking brake
|
900 rpm
|
|
|
|
Selector lever position "P",
"N"
"R", "D",
"3", "2", "1
|
775 rpm
700 rpm
|
|
|
|
· Select
TECH 1 mode "F8"
· Using
arrow keys, increase (1500 rpm) and decrease (1000 rpm) idle speed
|
Engine speed increases and decreases
|
· Throttle
valve gap too large or too small, (basic setting: alter only in emergencies,
see next page but one).
· Engine
takes in dead air.
· Trouble
code 21 and 22 set.
|
|
|
· Ignition
OFF
· Disconnect
plug from idle speed regulator M 66.
· Ignition
ON
· TECH 1 in
mode "F5" IDLE AIR CONTROL
|
|
|
|
|
· Measure
voltage:
from: wiring
harness plug Ter. A
to: wiring
harness plug Ter. B
|
greater than 11 V
|
|
|
|
from: wiring
harness plug Ter. C
to: wiring
harness plug Ter. D
|
greater than 11 V
|
· Carry
out visual check on plug connections.
· Wiring
harness defective.
· Control
unit defective.
· Lead
interruption,
from: control
unit K 57
to: idle
speed regulator M 66
|
|
|
· Ignition
OFF
· Measure
resistance of coils A - B and C - D
|
55 W to 65 W (cold)
45 W to 60 W (warm)
|
· Idle
speed regulator defective
|
|
|
· Ignition
OFF
· Remove
motor M 66
· Connect
plug to idle speed regulator M 66
· Ignition
ON
TECH 1 in mode "F5" IDLE AIR CONTROL
|
|
|
|
|
Compress valve cone lightly with thumbs
|
Valve cone moves visibly in and out
|
· Idle
speed regulator defective
|
|
|
· Additional
Causes
|
|
· Loose
contact in throttle valve potentiometer
· Throttle
shaft out of alignment
· Throttle
valve gap too large or too small, (basic setting: see next section).
· Engine
takes in dead air.
· Idle
speed regulator seat soiled.
· Exhaust
gas recirculation valve mechanically blocked
· Fault
in evaporation control system
· Spark
plugs defective
· Mixture
too lean or too rich.
· Battery
voltage too high / low
· Odometer
frequency sensor / instrument defective or circuit defective.
|
|
|
Basic adjustment of throttle valve, see Service Instructions
(alter in emergency only)
|
|
|
|
|
|
|
|
|
|
