|
No.
|
TECH 1 Display
|
Conditions for
Checking
|
Nominal Value
|
Trouble Codes
|
Terminal
|
|
|
05
|
ENGINE SPEED
|
Engine running at idle speed, operating temperature
|
|
35, 19
|
A 2 /B 3
|
|
|
|
|
Vehicles with MT
|
820 to 980 rpm
|
|
|
|
|
|
|
Vehicles with AT
|
750 to 910 rpm
|
|
|
|
|
The "ENGINE SPEED
" is dependent on various input signals and the control unit
programming.
If the actual value is not within the given nominal values,
the other sensor signals must be checked first.
|
|
Trouble - shooting:
|
Nominal Value:
|
Cause of Fault:
(If nominal value is not attained)
|
|
|
· Check
the inductive pulse pick - up signal P 35:
· Ignition
OFF
Disconnect the control unit plug
· Measure
voltage:
from: control
unit plug Ter. A 2
to: ground
|
less than 0.1 V
|
· Short
circuit in wiring harness
from: control
unit plug Ter. A 2
to: battery +
|
|
|
from: control
unit plug Ter. B 3
to: ground
|
less than 0.1 V
|
from: control
unit plug Ter. B 3
to: battery +
|
|
|
· Using
multimeter, measure resistance:
from: wiring
harness plug P 35 Ter. 1
to: control
unit plug Ter. A 2
|
less than 2 W
|
· Lead
interruption
from: wiring
harness plug P 35 Ter. 1
to: control
unit plug Ter. A 2
|
|
|
· Using
multimeter, measure resistance:
from: wiring
harness plug P 35 Ter. 2
to: control
unit plug Ter. B 3
|
less than 2 W
|
· Lead
interruption
from: wiring
harness plug P 35 Ter. 2
to: control
unit plug Ter. B 3
|
|
|
· Using
multimeter, measure resistance:
from: wiring
harness plug P 35 Ter. 1 and 2
to: ground
|
greater than 100 kW
|
· Short
circuit in wiring harness
from: wiring
harness plug P 35 Ter. 1 or 2
to: ground
|
|
|
· Using
multimeter, measure resistance:
from: wiring
harness plug P 35 Ter. 3
to: control
unit plug Ter. A 12
|
less than 2 W
|
· Lead
interruption in shielding
|
|
|
· Further
fault possibilities:
|
|
· Defective
inductive pulse pick - up
· Burrs
on increment disc (58 - toothed segment disc)
· Gap
between inductive pulse pick - up and increment disc incorrect.
See service literature.
|
|
|
· Connect
control unit wiring harness plug
· Connect
pulse pick - up plug P 35.
· Engine
running at idle speed, operating temperature
· Select
TECH 1 mode "F8", increase and decrease idle speed with
the arrow keys.
|
Engine speed increases and decreases
|
· Carry
out test step 04.
|
|
|
· Idle
speed too high or uneven.
|
|
· Loose
contact in throttle valve potentiometer
· Throttle
shaft out of alignment
· Throttle
valve gap too large or too small, (basic setting: alter only in case of
emergency, see Service Instructions).
· Exhaust
gas recirculation valve mechanically blocked
· Fault
in evaporation control system
· Engine
takes in dead air.
· Idle
speed regulator seat soiled.
· Spark
plugs defective
· Mixture
too lean or too rich (see test step 10).
· Battery
voltage too high / low
· Odometer
frequency sensor / instrument defective or circuit interrupted.
|
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