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Home >> Volvo >> 2001 >> S40 L4-1.9L Turbo VIN 29 B4204T3 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> TCM Codes (Transmission Control Module) >> TCM-0027 >> Incorrect Gear Ratio

Incorrect Gear Ratio






Incorrect gear ratio

Checking for contact resistance and oxidation




- Ignition off
- Check the transmission control module (TCM), transmission output speed sensor and transmission connectors. Check for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Test drive the car according to Test drive schedule, description, AW55-50/51SN Test Drive Schedule, Description.
When test driving, the oil temperature must be above 20°C. Check for transmission malfunction. Listen for mechanical noise from the transmission.





Is the function of the transmission OK?

Yes - Checking the oil quality and the oil level in the transmission

No - Replacing the transmission

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Checking the oil quality and the oil level in the transmission

Note! Transmission fluid quality and level are extremely important for transmission function. Therefore it is imperative that these are correct. In addition the oil level is dependent on oil temperature.




- Ignition on
- Read off the oil temperature.
Check the oil level. If the oil level is low check for leakage. Top up with oil.
Check the quality of the oil.
Replace the transmission fluid if the fluid smells burnt.
Check the transmission fluid for metal swarf. Take a sample using the dip stick.
Replace the transmission if the transmission fluid contains metal swarf.

Other information:
- To replace the transmission fluid, see Oil, changing, AW55-50/51SN Changing Oil
- To check the level, see Checking and adjusting the oil, AW55-50/51SN Checking Oil Level
- To check the quality of the transmission fluid, see Oil, Quality Check.

Select an alternative below:
1. No fault detected
2. Transmission fluid replaced, the level was low or quality was poor
3. The transmission fluid contains metal swarf.






1 - Checking the adjustment of the gear-shift position sensor

2 - Resetting the oil quality counter

3 - Replacing the transmission

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Checking the adjustment of the gear-shift position sensor




- Ignition on
- Read off the position of the gear-shift position sensor.
Move the gear selector around the different gear positions a number of times. Check that the gear position is updated. The selected position must be the same as that displayed in VIDA. If the display shows an undefined position (OR for example) the transmission cable needs adjusting.

Note! An undefined position may be displayed between the fixed gear positions. This is not a fault.

Remedy as necessary.

Other information
- To adjust the mechanical transmission cable, see Adjusting the mechanical cable for the transmission, AW55-50/51SN Adjustments.









Is the gear-shift position sensor incorrectly adjusted?

Yes - Verification

No - Checking the transmission output speed sensor signal

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Resetting the oil quality counter





Resetting the "Transmission fluid change" counter

Resetting the "Transmission fluid change" counter

Hint: The transmission control module (TCM) has a counter for the oil quality. The counter counts up if the transmission is exposed to too high a load or an ambient temperature that is too high. If the counter is not reset when the oil is drained or changed, there is a risk that a diagnostic trouble code (DTC) will be stored incorrectly. Therefore it is important that the "Transmission oil change" counter is reset.

Note! This only applies when the transmission fluid is changed and when the fluid is changed during repairs to the transmission temperature sensor.




- Ignition on.
Click on the VCT2000 symbol to reset the counter.





Continue - DONE

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DONE - Verification

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Checking the transmission output speed sensor signal




- Ignition off
- Raise the car so that the drive wheels can rotate freely
- Start the engine and let it run at idle speed
- Gear selector in position D
- Read off the transmission output speed signal.
Check that the speed increases with engine speed (RPM).

Note! A diagnostic trouble code (DTC) may be stored in the ABS system when the rear wheels are stationary and the front wheels rotate. Erase any diagnostic trouble codes (DTCs) in the ABS system after completing fault-tracing.

Other information:
- To disconnect the transmission control module (TCM), see Replacing the transmission control module (TCM), AW55-50/51SN Service and Repair
- To disconnect the transmission connectors, see Transmission connectors, AW55-50/51SN Transmission Connectors
- For information about signals, see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description.





Does the speed increase with engine speed (RPM)?

Yes - Checking the transmission input speed sensor signal

No - Checking wiring and sensors

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Checking wiring and sensors




- Ignition off
- Connect the breakout box.
Check the power supply cable between terminal #2 on the white 2-pin transmission output speed sensor connector (control module side) and control module terminal #9. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the signal cable between terminal #1 on the white 2-pin transmission output speed sensor connector (control module side) and control module terminal #10. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Hint: With the control module connected, the transmission output speed sensor disconnected and the ignition on, the voltage between transmission output speed sensor connector terminals #1 and #2 should be 1-3 V below Ubat.

Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting the breakout box, AW55-50/51SN Connecting The Breakout Box
- To disconnect the transmission connectors, see Transmission connectors, AW55-50/51SN Transmission Connectors
- To check or replace the transmission output speed sensor, see Replacing the speed sensor, AW55-50/51SN Removal and Replacement
- For information about signals, see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description.









Continue - Verification

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Checking the transmission input speed sensor signal




- Ignition off
- Gear selector in position P
- Start the engine and let it run at idle speed
- Read off the transmission input speed.
Check that the transmission input speed is updated.
Compare with the engine speed (RPM).

Other information:
- To disconnect the transmission control module (TCM), see Replacing the transmission control module (TCM), AW55-50/51SN Service and Repair
- To disconnect the transmission connectors, see Transmission connectors, AW55-50/51SN Transmission Connectors
- For information about signals, see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description.





Does the transmission input speed increase with engine speed (RPM)?

Yes - Test driving the transmission

No - Checking wiring and sensors

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Checking wiring and sensors




- Ignition off
- Connect the breakout box.
Check the speed sensor cable for power supply between control module terminal #11 and terminal #2 on the black 2-pin transmission connector (control module side). Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the signal cable between control module terminal #12 and terminal #1 on the black 2-pin transmission connector (control module side). Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Check for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Hint: With the control module connected and the ignition on, the voltage between transmission output speed sensor connector terminals #1 and #2 should be 1-3 V below Ubat.

Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting the breakout box, AW55-50/51SN Connecting The Breakout Box
- To disconnect the transmission connectors, see Transmission connectors, AW55-50/51SN Transmission Connectors
- To replace the transmission input speed sensor, see Replacing the engine speed (RPM) sensor, AW55-50/51SN Service and Repair
- For information about signals, see Signal description. Transmission control module (TCM), AW55-50/51SN Signal Description.













Continue - Verification

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Replacing the transmission
- Fault-tracing indicates an internal fault in the transmission. Replace the transmission according to Replacing the transmission, AW55-50/51SN Replacing The Transmission.






Continue - Verification

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Test driving the transmission
Test drive the car according to Test drive schedule, description, AW55-50/51SN Test Drive Schedule, Description. When test driving, the oil temperature must be above 20°C.
Look out for any transmission malfunction.





Is the transmission operating correctly?

Yes - Fault-tracing information

No - Replacing the transmission control system

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Replacing the transmission control system
The previous tests indicate that there is a fault in the transmission control system.
Try a new control system according to Replacing the solenoids and control system, AW55-50/51SN Service and Repair.





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 solenoids 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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Fault-tracing information
The control module has previously registered a fault. The fault is now no longer present. A test of the transmission function indicates that everything is now OK.

Continue - No Fault Found

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off
- Reconnect the connectors, components, etc.
- Ignition on
Test drive the vehicle following: Test drive schedule, description Test Drive Schedule, Description
During the test drive, oil temperature should be over 20 °C.
Note any deviations in transmission function.

Does the transmission function flawlessly?

Yes - VERIFIED

No - 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 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 for contact resistance and oxidation

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