No communication with the electronic unit
Symptom: The seat can be operated by the manual controls but when the manual control is released the seat returns to its original position.
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No communication with the electronic unit
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1.
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that the ignition is switched on and the electronic unit is supplied with battery voltage.
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2.
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that battery voltage is present across pins 16 and 4 of the test socket (if the voltage is correct, the ISAT display will light up when the ISAT is plugged into the test socket).
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3.
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the connection between the test socket and the electronic unit.
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4.
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If the ISAT still cannot establish communication with the electronic unit:
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Symptom 1
The seat can be operated by the manual controls but when the manual control is released the seat returns to its original position.
Probable cause of fault 1:
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Fault in the memory button assembly. The memory buttons are constantly activated.
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Diagnostic procedure 1:
Turn to page 852-52 "Checking the operation of pushbuttons and manual controls".
Symptom 2
The electronic unit is completely dead and does not react in any way to commands from either the memory pushbuttons or the manual controls.
Probable cause of fault 2:
The electronic unit has detected an internal fault of such a nature that all functions have been blocked.
Diagnostic procedure 2:
Turn to page 852-55, "Before control module replacement".