Fault-Tracing
Fault tracing
Checking the gear system
Fault-tracing information
Checking the gear system
Problems that the customer may experience are hard shifts or slipping shifts. The following test-drive contains several different driving situations that may provoke these symptoms if the transmission is damaged.
Note! It is important that the transmission oil is above 70 °C before the test-drive starts!
Test 1
1. Driving at 100 km/h, 6th gear.
2. Perform a kickdown to 4th gear.
3. Let the transmission automatically shift up to 5th gear.
4. Let up the accelerator pedal and let the transmission shift up to 6th gear.
Test 2
1. Driving at 100 km/h, 6th gear.
2. Slight uphill grade, press accelerator pedal until you obtain shifting 6-5, not kickdown.
Test 3
1. Driving at 80 km/h.
2. Move the gear selector to position M and engage 6th gear.
3. Perform a kickdown and shift 6-5, 5-4, 4-3 at the same time.
4. Then upshift immediately to 6th gear.
Test 4
1. Stationary vehicle, engine running, parking brake applied, brake activated with left foot, gear selector in position R.
2. Press down the accelerator pedal (brake still activated).
Note! Let up the accelerator pedal in case of noise or slipping.
Test 5
1. Stationary vehicle, engine running, parking brake applied, brake activated with left foot, gear selector in position D.
2. Press down the accelerator pedal (brake still activated).
Note! Let up the accelerator pedal in case of noise or slipping.
If the symptoms hard shifts or slipping shifts arise during the test-drive, the transmission's control system must be replaced.
Other information
- Control system, replacing, B8444S, TF-80SC AWD, B6324S, TF-80SC AWD Control System, Replacing
Is the function OK?
Yes - DONE
No - FAULT FOUND
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DONE - Checking solenoid SLC1
FAULT FOUND - Replacing the control system
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Checking solenoid SLC1
- Ignition on.
- Activate solenoid SLC1 by clicking the VCT2000 symbol.
Read the current through the circuit for solenoid SLC1. The current should oscillate between 100 and 950 mA.
The fault is in the control system if the current does not oscillate. If the current varies and a clicking noise is heard, the control signal from the Transmission control module (TCM) and the solenoid's function is OK.
Note! Depending on the transaxle and oil temperature, the noise level from the solenoids may vary considerably. When the transaxle is hot or extremely cold, the noise level may be extremely low. Use a stethoscope.
Hint: To obtain a "click" more easily, move the gear selector to different positions and then try to activate the solenoid again.
Is the control signal of the solenoid OK?
Yes - Replacing the transmission
No - Replacing the control system
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Replacing the transmission
The transmission control module (TCM) has registered an internal malfunction in the transmission. Replace the transmission.
Other information
- Replacing the gearbox, B8444S, TF-80SC AWD Removal and Replacement
Continue - Resetting adaptation and the fluid quality counter
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Resetting adaptation and the fluid quality counter
Resetting adaptation
Resetting adaptation and counter for "Transmission oil, changing"
Hint: The transmission has torque-controlled, adaptive pressure control. The pressure control means that the transmission itself controls the pressure during each shift sequence in order to avoid harsh shifting. Each shift is assessed by the transmission control module (TCM) and is stored in the internal memory, which results in compensation for wear in the transmission and clutch. In order for the transmission to function correctly after repair, it is important to reset the adaptation in the memory. Since the oil is changed during the repair, the counter for "Transmission oil, change" shall also be reset. If the counter is not reset when draining/changing oil, there is a risk that a diagnostic trouble code may be generated under incorrect conditions.
Note! This applies only if the transmission or one of the components in the transmission have been replaced.
- Ignition on
Activate reset of the adaptation and the counter by clicking on the symbol for VCT2000.
Continue - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the components, reconnect the connectors etc.
- The gear shift position sensor for the transmission must be calibrated if the control module has been disconnected.
Hint: Save a bookmark. Cancel fault-tracing and select Vehicle communication.
- Start the engine.
Test drive the vehicle following: Test drive schedule, description, TF-80SC AWD Test Drive Schedule, Description
Check that the transmission does not display any obvious function faults.
Note! When test driving, the oil temperature must be above 20° C.
Is the function OK?
Yes - Troubleshooting procedure complete
No - 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 solenoid SLC1
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Replacing the control system
Replace control system as follows: Control system, replacing, B8444S, TF-80SC AWD, B6324S, TF-80SC AWD Control System, Replacing
Continue.
Continue - replace"
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Resetting the adaptation and the counter for "Transmission oil, replace"
Resetting adaptation, B8444S, TF-80SC AWD
DONE - Verification
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