Engine speed
Output signal to main instrument display panel
Fault symptoms
Tachometer out of order. If a TCS/TCM diagnostic trouble code is present, follow the
diagnostic procedure described for that trouble code.
Diagnostic help
The tachometer can be activated with the ISAT scan tool.
The command activates the Motronic control module, causing it to send a 50 Hz
signal to the tachometer. The tachometer should then indicate about 1000 rpm for 30
seconds.
Diagnostic procedure
1. Check the control module connection
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Unplug the main instrument display
panel connector.
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Take a voltage/frequency reading
across:
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Connect the ISAT Scan
Tool.
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Turn the ignition switch to the ON
position.
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The command activates output voltage, which should be about 5.5-6 V and 50
Hz.
Is the reading obtained OK?
Continue fault diagnosis as described in "Electrical system, main instrument
display panel"
.
Continue with point 2.
2. Check the wiring
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Check the continuity of the wiring
between pin 47 of the Motronic control module and pin 6 of the main instrument display
panel.
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Is the lead OK?
Continue as described in
.
Repair or replace the
wiring.
