Before control module replacement
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Before control module replacement
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When all tests have been carried out according to the relevant
diagnostics procedure or by manual fault diagnosis without any faults
having been found, it is natural to assume that the control module is
at fault.
In view of the fact that the control module is an exceptionally
high-quality component and also extremely expensive, it is important to
verify the diagnosis as far as possible.
Therefore, go through all the points very carefully before definitely
pointing to the MOTRONIC control module as the cause of the fault.
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1.
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Check once again that every
single point in the fault diagnosis
programme of the relevant diagnostic trouble code has been carried out.
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2.
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Study the wiring diagram of the circuit in question and make sure
you understand how it works. Relevant parts of the technical
description and the electrical descriptions of operation in Service
Manual 3:2 "Electrical system" may be of assistance in this
respect.
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3.
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Check all grounding points. If you have already done so, do it once
again. Check that power ground and signal ground are electrically
separate.
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4.
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Check the voltage supplied to the control module.
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5.
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Go once more through each point listed under "Points to remember"
on
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6.
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If the original fault still persists in spite of this, then the
MOTRONIC control module will have to be replaced.
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All control modules are more or less sensitive to static electricity
and, if handled carelessly or incorrectly, may be damaged so seriously
that they no longer work properly. It is therefore important to ensure
that the following rules are observed at all times when a control
module is removed or replaced for any reason.
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Avoid unplugging or removing a
control module unless absolutely
necessary.
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Never touch the connector pins and never place the control module in
such a way that the connector pins may come into contact with foreign
objects.
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Before unpacking a new control module, ground the packaging to the car
body. Open the packaging as shortly as possible before installing the
control module.
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When handling or working on control modules it is important to ground
yourself from time to time. This is particularly important when you
have been sitting in the car, when changing your position, or when
moving round the car. It is even more important in a climate with
extremely dry air (e. g. during the winter in cold markets).
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Avoid wearing clothes made of synthetic (man-
made) fibres.
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Furthermore, always handle control modules which are suspected of being
defective in the same manner. This will greatly improve the chances of
determining the cause of the fault.
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