Engine rpm signal to the MIU, TCS and AF22control modules
Symptom: Diagnostic trouble codes generated in the MIU, TCS and/or AF22
systems
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Engine rpm signal to the MIU, TCS and AF22
control modules
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Fault symptom
Diagnostic trouble codes generated in the MIU, TCS and/or AF22
systems
1.
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Start the engine and use the
ISAT command "ENGINE RPM SIGNAL" in
the "READ ON/OFF" menu. If the control module sends out engine rpm
signals, the ISAT display should read "ACTIVE".
If the ISAT shows "INACTIVE", turn to
for further
diagnostic instructions.
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2.
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If the ISAT display reads "ACTIVE", clear all diagnostic
trouble codes in the MIU, TCS and/or AF22 systems and drive the car to
see whether any are generated afresh. If they are, continue as
described below.
With the ignition switched off, connect a BOB to the MOTRONIC control
module and cable. Check that there is a signal of about 6.5 V and 40 Hz
on pin 43 at idling speed. At 2500 rpm the signal should be about 6.5 V
and 125 hz.
If the signal is OK, the fault lies either in the leads connected to the
MIU, TCS and/or AF22 control modules or in any of these systems.
If there is no output signal on pin 43, it may be on account of a short
circuit to ground/batt+ in any of the leads connected to the above
systems. Rectify any faults.
If there is no short circuit, turn to
for further diagnostic
instructions.
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