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No.
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TECH 1 Display
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Conditions for
Checking
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Nominal Value
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Trouble Codes
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Terminal
|
|
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28
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ENGINE
SPEED
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Engine running at idle speed,
operating temperature
Switch off all consumers
|
|
19,
31
|
48,
49
|
|
|
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20 SE engine
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670 to 1030 rpm
|
|
|
|
|
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X 20 SE engine
Note:
See FO: Data List, test step 27
|
670 to 1030 rpm
|
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Note:
· In the Motronic
M 1.5.4, trouble code 31 is always set when the ignition is
switched ON. This code can either be displayed on TECH 1 or flashed out
by short - circuiting the diagnostic plug with
KM - 640 in switch position "B". When the control
unit receives engine speed signals from the inductive pulse pick - up on
starting, trouble code 31 is automatically deleted and does not remain
stored.
If trouble code 31 is not deleted on starting, a
fault is present and trouble - shooting should be commenced.
· Trouble code
19 is only set if there is a very brief interruption of the engine speed
signal at engine speeds higher than 2000 rpm.
If the interruption is longer and at engine speeds lower
than 2000 rpm, the data stream from the control unit to
TECH 1 is interrupted.
Test steps 27 and 28 can be
divided into 3 parts
A) Engine does not start, trouble code 31 remains
stored
B) Brief engine speed interruption, trouble code
19 may be stored
C) Engine speed deviates from nominal values, no trouble
code stored
|
|
Notes on Trouble - shooting:
|
Nominal Value:
|
Cause of Fault:
|
|
|
A) Engine
does not start, trouble code 31 remains stored:
· Check plug connection from inductive
pulse pick -up P 35 to control unit
|
firm connection
|
· Loose contact
· Corroded contacts
|
|
|
· Connect checking
spark plug to ignition cable of cylinder 1 and 4
· Start engine
|
Checking spark plugs ignite
|
If no spark
· Lead interruption from - ignition coil
L 2 / Ter. 1 to control unit K 61 / Ter. 1
- ignition
coil L 2 / Ter. 2 to Ter. 15
- ignition
coil L 2 / Ter. 3 to control unit K 61 / Ter. 20
- ignition
coil to spark plug cylinder 1
- ignition
coil to spark plug cylinder 4
|
|
|
· Disconnect
Motronic control unit K 61 from wiring harness
· Using multimeter,
check resistance at control unit plug K 61 / Ter. 48 to Ter. 49
|
0.5 to 0.8 kW
|
· Pulse pick - up
P 35 defective
|
|
|
· Check resistance
at control unit plug K 61 / Ter. 48 to Ter. 19 and K 61 / Ter. 49 to Ter. 19
Nominal values are attained
|
infinite
|
· Short circuit from
pulse pick
- up P 35 / Ter. 1 to Ter. 3
- pulse pick
- up P 35 / Ter. 2 to Ter. 3
· Toothed disc /
teeth corroded
· Metal chippings on
pulse pick - up
|
|
|
B) Brief engine speed
interruption, trouble code 19 may be stored:
|
|
· as for A) trouble
code 31
· Check shielding on inductive pulse pick
- up plug P 35 / Ter. 3 on control unit side to ground.
|
as for A) trouble code 31
0 W
|
· as for A) trouble code 31
· Interference pulses in engine speed
signal lead
|
|
|
· Check that segment
disc is firmly seated and undamaged (removal of oil pan required)
Nominal values are attained
|
|
· Segment disc loose
· Teeth damaged
· Replace pulse pick
-up
|
|
|
C) Engine speed deviates from
nominal values, no trouble code stored:
See F0:DATA LIST, test step 17
and F5: ACTUATOR TEST, test step 04
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