Part 1
Incorrect gear ratio
Checking the transmission oil level
- Ignition on
- Go into scrolling values
- Read off the oil temperature.
Check the transmission oil level according to Checking oil level Checking Oil Level. Check the level at different temperatures.
Is the level OK?
Yes - Checking the gear-shift position sensor adjustment
No - Checking for oil leakage
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Checking for oil leakage
Check for oil leaks. Remedy as necessary. Top up the oil to the correct level according to Checking oil level Checking Oil Level.
Note! If the car has been driven with the oil level too low damage may have been caused to the transmission. Test drive according to to check if the transmission is OK.
Continue - Test driving
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Checking the gear-shift position sensor adjustment
- Ignition off.
Check the gear-shift position sensor adjustment according to Checking and adjusting the gear-shift position sensor Adjustments.
Adjust if necessary.
Was the adjustment OK?
Yes - Checking for mechanical faults in the transmission
No - Test driving
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Checking for mechanical faults in the transmission
- Ignition on
- Make a note of diagnostic trouble code (DTC) frozen values
- Erase the diagnostic trouble code (DTC).
Test drive car. Repeat the driving conditions under which the diagnostic trouble code (DTC) was stored. Monitor the automatic transmission warning light. If the warning lamp starts flashing a diagnostic trouble code (DTC) has been stored. Make an immediate note of abnormalities in the operation of the transmission before and after the warning lamp started flashing.
Note! If the diagnostic trouble code (DTC) is stored permanently, the transmission control module (TCM) activates the emergency "Limp Home" program. The transmission will not operate normally. See Emergency programs Emergency Programs In The Event Of A Fault for "Limp Home" symptoms.
Is the transmission exhibiting any obvious mechanical malfunctions or making a noise?
Yes - Fault-tracing information
No - Connecting the breakout box
Connecting the breakout box
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Fault-tracing information
Terminate the current fault-tracing. Add mechanical symptoms to the symptoms list. Fault-trace the symptoms.
Continue - No Fault Found
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Connecting the breakout box
Connecting the breakout box
951 1355 Adapter 42-pin 951 1355 Adapter 42-pin 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428
Information
Connecting the breakout box to AW50-42
Is the breakout box connected to the control module?
Yes - CONNECTEDReturn to fault-tracing.
No - NOT CONNECTED
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CONNECTED - CONNECTED
NOT CONNECTED - Connecting the breakout box
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Connecting the breakout box
Connecting the breakout box
981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 951 1355 Adapter 42-pin 951 1355 Adapter 42-pin
Connecting the breakout box
Caution! The voltage supply to the control module must be disconnected when disconnecting the breakout box. Failure to observe this procedure could seriously damage the control module.
- Ignition off
- Expose and disconnect the AW50-42 transmission control module (TCM) according to Replacing the transmission control module (TCM) .
- Control module disconnected.
Connect adapter 951 1355 Adapter 42-pin 951 1355 Adapter 42-pin to the control module connector (wiring side). Connect breakout box 981 3190 Replaced by 9511428 981 3190 Replaced by 951 1428 to the adapter.
Note! Ensure that the adapter is the right way around.
Continue - DONE
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DONE - Checking the ground terminal
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Checking the ground terminal
- Ignition off.
- Control module disconnected.
- Switch off all power consuming equipment, such as courtesy lighting, radio etc.
Connect an ohmmeter between terminal 1 on the breakout box and the battery negative terminal.
The ohmmeter should read approximately 0 ohms.
OK - Return to the fault-tracing procedure where it was interrupted.
No Fault Found
Not OK - Checking for an open-circuit, contact resistance and oxidation
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Checking for an open-circuit, contact resistance and oxidation
Check ground terminal 31/20 and the lead between the ground terminal and control module #1 for open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault and contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Check the ground lead between the battery and the body for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault and contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Continue - Verification
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Verification
Verification
Hint: After repairs have been completed they must be verified as follows to ensure that the fault has been eliminated:
- Ignition off
- Switch off all power consuming equipment, such as courtesy lighting, radio etc.
- Control module disconnected
Connect an ohmmeter between #1 on the breakout box and the battery negative terminal.
The ohmmeter should read approximately 0 ohms.
OK - VERIFIED
Not OK - VERIFICATION FAILED
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VERIFIED - FAULT FOUND
VERIFICATION FAILED - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
The fault should be diagnosed and remedied. Since this is not the case the fault-tracing process has failed.
Complete the fault-tracing for those fault or try again.
Do you want to terminate fault-tracing at this time?
Yes - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Connecting the breakout box
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CONNECTED - Checking the transmission speed sensor signal cable (-)
FAULT FOUND - Checking the transmission speed sensor signal cable (-)
No Fault Found - Checking the transmission speed sensor signal cable (-)
FAULT-TRACING FAILED - Checking the transmission speed sensor signal cable (-)
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Checking the transmission speed sensor signal cable (-)
- Ignition off
- Control module disconnected.
Connect an ohmmeter between:
- terminals #39 and #1 on the breakout box.
The ohmmeter should read infinite resistance.
OK - Checking the signal from transmission speed sensor
Not OK - Checking the transmission speed sensor
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Checking the transmission speed sensor
- Ignition off
- Disconnect the black 2-pin transmission connector. For further information about connectors, see Transmission connectors Transmission Connectors.
Connect an ohmmeter between the black 2-pin transmission connector terminal #1 (transmission speed sensor side) and ground.
The ohmmeter should read infinite resistance.
OK - Checking for a short-circuit
Not OK - Replacing the component
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Checking for a short-circuit
Check cable between black 2-pin transmission connector:
- terminal #1 and control module terminal #39.
for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault.
Continue - Verification
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Checking the signal from transmission speed sensor
- Ignition off
- Connect the control module.
- Connect a frequency meter between terminals #39 and #25 on the breakout box
- Raise the car and remove the front wheels during the test
- Engine idling
- Air conditioning (A/C) system turned off
- Shift the gear selector to position D so the front wheels begin to rotate
- Increase the engine speed (RPM) to approximately 2000 rpm
- Keep the engine speed (RPM) steady.
Note! When the rear wheels are stationary and the front wheels rotate, diagnostic trouble codes (DTCs) may be stored in the ABS system. Erase any diagnostic trouble codes (DTCs) stored in the ABS system after fault-tracing.
The multimeter (frequency meter) should give a stable reading (Hz) when the engine speed is steady and the transmission is not shifting.
Note! Ensure that the front wheels are not rotating when the gear selector is moved.
Is the frequency stable?
Yes - Checking the transmission speed sensor signal cable (-)
No - Checking the transmission speed sensor resistance
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Checking the transmission speed sensor resistance
- Ignition off
- Disconnect the control module.
Connect an ohmmeter between:
- terminals #39 and #25 on the breakout box.
The ohmmeter should read 300-600 ohms.
OK - Checking for sources of interference
Not OK - Checking the transmission connector
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Checking for sources of interference
Check that the transmission speed sensor wiring is not too near sources of interference, such as electric motors, ignition cables, mobile telephone cables etc.
Continue - Test driving
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Checking the transmission connector
- Ignition off
- Control module disconnected.
- Disconnect the black 2-pin transmission connector
- Check the black 2-pin transmission control module (TCM) connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring And Terminals. Permanent Fault
- Connect the transmission connector.
Connect an ohmmeter between:
- terminals #39 and #25 on the breakout box.
The ohmmeter should read 300-600 ohms.
OK - Fault-tracing information
Not OK - Replacing the component
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Fault-tracing information
The cause of the diagnostic trouble code (DTC) was loose connections in the transmission connector.
Continue - Verification
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Replacing the component
- Ignition off.
Try a new transmission speed sensor according to Replacing the engine speed (RPM) sensor Service and Repair.
Continue - Verification
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