Checking SPEED SIGNAL
Symptom: The soft top can be operated even though the car is in motion.
Fault symptoms
The soft top can be operated even though the car is in motion.
Conditions
Open circuit or short to ground in the lead between the ABS control module and the TSAS control module.
Diagnostic help
The speed can be read with the diagnostic tool.
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Connect the diagnostic tool.
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Turn the ignition switch to the ON position.
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Read the speed while the car is in motion or while rotating the right rear wheel.
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At speeds above 3 km/h, the diagnostic tool should display >0 km/h, otherwise it should display 0 km/h
It should not be possible to operate the soft top at speeds above 3 km/h.
Diagnostic procedure
1. Read the speed with the diagnostic tool
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Connect the diagnostic tool.
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Turn the ignition switch to the ON position.
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Drive the car or rotate the right rear wheel.
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The diagnostic tool should display >0 km/h
Is the value correct?
Continue with step 3.
Continue with step 2.
2. Check the speed signal from ABS
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Unplug control module connector K42.
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Turn the ignition switch to the ON position.
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Connect test lamp 86 11 857 between pin 12 (K42) and ground.
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Rotate the right rear wheel.
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The test lamp should flash.
Does the test lamp flash?
Continue with step 3.
Check and if necessary rectify the relevant lead. If there is no fault in the lead, continue fault diagnosis with Service Manual 5:2 ABS. Continue with step 3.
3. Final check
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Clear the diagnostic trouble codes.
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Activate the soft top with the ROOF button and operate it for a few cycles
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Make sure the soft top is functioning correctly and that no diagnostic trouble codes are generated.
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Make sure the soft top cannot be operated while the car is in motion (>3 km/h).
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Is the function correct?
The fault has been rectified.
Change the control module as described in
