Signal Missing. Permanent Fault
Signal missing. Permanent fault
Checking line pressure solenoid SLT
- Ignition off.
- Remedy the control module and automatic transmission connector A for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Reinstall the components, reconnect the connectors etc.
- Ignition on.
- Read off the current through the solenoid circuit.
- Depress the accelerator pedal (AP) slowly.
The cause of the fault was contact resistance or oxidation if the current reduces as the accelerator pedal (AP) is depressed.
Other information:
- To disconnect transmission connector A, see Replacement Of Control System Cable Harness With Oil Temperature Sensor.
- To disconnect the control module, see Replacing the gearbox control module (TCM) Replacing the Gearbox Control Module (TCM).
Does the current reduce when the accelerator pedal (AP) is depressed?
Yes - FAULT FOUND
No - Checking the wiring
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Checking the wiring
- Ignition off.
- Disconnect transmission connector A.
Check the cable between control module #A52 (#A52)and transmission connector A (control module side) #24 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the cable between control module #A70 (#B10) and transmission connector A (control module side) #25 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.
Other information:
- To connect the breakout box, see Connecting the breakout box, B5234T9, B5244T7 Connecting The Breakout Box.
- To disconnect transmission connector A, see Replacement Of Control System Cable Harness With Oil Temperature Sensor.
- For information about signals, see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description AW50-42.
Was a fault found in the wiring?
Yes - Verification
No - Checking solenoid SLT
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Checking solenoid SLT
- Ignition off.
- Transmission connector A disconnected.
Check solenoid SLT by measuring the resistance between #24 and #25 on transmission connector A. The ohmmeter should read 5-5.6 ohms (at 20°C).
Other information:
- To disconnect transmission connector A, see Replacement Of Control System Cable Harness With Oil Temperature Sensor.
- For information about signals, see Signal Description AW50-42.
Was the resistance OK?
OK - Replacing the control module
Not OK - Replacing the transmission
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Replacing the control module
The control module has registered an internal fault.
Caution! A new control module is delivered without software. The control module must be programmed in order to function after replacement.
For further information about programming and replacing the control module, see Replacing the gearbox control module (TCM) Replacing the Gearbox Control Module (TCM).
Continue - Verification
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Replacing the transmission
Hint: Transmission AW 50-55SN must be replaced in the event of internal faults during the first year on the market.
- Ignition off.
Replace the transmission according to Removing the transmission Transmission, Removal.
Continue - Resetting the adaptation and oil quality counter
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Resetting the adaptation and oil quality counter
Resetting the adaptation
Resetting adaptation and the counter for "Transmission oil change"
Hint: The transmission has torque controlled adaptive pressure control. Pressure control means that the transmission regulates the pressure itself during each gear shift. This avoids harsh gear shifting. Each gear shift is evaluated by the control module and stored in the memory. This allows for compensation for wear and tear in the transmission and clutch. It is important that the adaptation in the memory is reset after the transmission has been repaired. This is to ensure normal operation. The oil is replaced during repair; the "Transmission oil change" counter must be reset. If the counter is not reset when the fluid is drained and replaced, there is a risk that a diagnostic trouble code (DTC) will be stored in incorrect circumstances.
Note! This applies only if the transmission or one of the components in the transmission have been replaced.
- Ignition on.
Click on the VCT2000 symbol to reset the adaptation and counter.
Continue - DONE
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DONE - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reconnect connectors, reinstall components etc.
- Start the car.
- Depress the accelerator pedal (AP) slowly.
- Read off the current through the solenoid circuit.
The current should decrease as the accelerator pedal (AP) is depressed.
Does the current decrease?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - FAULT FOUND
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Fault-tracing information
Information
Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.
Do you want to exit fault-tracing?
Yes - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking line pressure solenoid SLT
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