P0726, P0727
Symptom: CHECK GEARBOX warning lamp on.
Engine RPM. Signal Faulty
Engine RPM. No Signal
Fault symptoms
CHECK GEARBOX warning lamp on.
Conditions
P0726:
Engine speeds in excess of the values below for at least 10 seconds.
7200 rpm (B234l engine)
7200 rpm (B204l engine)
P0727:
Transmission input speed greater than 2000 rpm for more than 5 seconds and signal to control module absent.
Check the wiring
Jiggle the wiring harness at several points and in different directions to reveal intermittent breaks and short circuits in the various leads. Observe the multimeter, test lamp or diagnostic instrument while carrying out this check.
Diagnostic procedure
1 Check the output signal from the engine management system
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Unplug the control module connector.
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Connect a test lamp to the connector between:
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Connect a diagnostic tool.
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Turn the ignition key to the ON position.
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Select the relevant engine management system.
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Select "
Data Display / Output Control (New)"
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Select “
Gearbox Input RPM"
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The lamp should flash.
Is the function OK?
Continue with step 3.
Continue with step 2.
2 Check the speed input lead
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Check the lead between TCM pin 29 and
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with respect to short/open circuits.
Is the lead OK?
Continue fault diagnosis in the Service Manual for the relevant engine management system.
Rectify any faults. Continue with step 3.
3 Final check
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Clear all diagnostic trouble codes in the system.
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Perform a driving cycle:
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Drive the car at varying loads and engine speeds for 5 min.
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Evaluate the driving cycle:
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Make sure the trouble code has not recurred.
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Has the trouble code recurred?
Continue with
Diagnostic procedure before replacing control module
The steps taken to rectify the fault were correct.
