Code No. P2859:
Auxiliary Gearbox Gear 1 Incorrect Ratio
DIAGNOSTIC FUNCTION
The CVT-ECU determines that the system is defective when the auxiliary gearbox remains
the gear ratio is abnormal although the ECU commands the 1st gear.
JUDGEMENT CRITERIA
- The ECU determines that the gear ratio is abnormal when the all of the conditions
below are satisfied for 1.5 seconds.
- The vehicle is stationary (The vehicle speed remains
5 km/h or less for 0.12 seconds)
- A certain period has elapsed after the shift control is complete.
- The auxiliary gearbox is commanded to the 1st gear.
- The high clutch oil pressure switch is ON.
- The target pressure for the high clutch is 0 MPa or less.
- If all of the conditions below are satisfied while the vehicle is being driven,
the CVT-ECU determines that the gear ratio is abnormal.
- Deceleration ratio remains less than -0.05 G for 0.2
seconds.
- The ECU commands the 1st gear to the auxiliary gearbox.
- The actual gear ratio of the auxiliary gearbox deviates by ±50%
or
more from the 1st gear ratio (1.821) for 0.2 seconds.
- If all of the conditions below are satisfied while the vehicle is being driven,
the CVT-ECU determines that the gear ratio is abnormal.
- The ECU commands the 1st gear to the auxiliary gearbox.
- The actual gear ratio of the auxiliary gearbox deviates by ±10%
or
less from the 2nd gear ratio (1,000) for 0.5 seconds.
PROBABLE CAUSES
- Malfunction of the CVT assembly (Faulty high clutch and reverse brake solenoid
valve or valve body assembly)
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STEP 1. Check the following connector
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Check the terminals for a contact status problem and internal short circuit.
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Q.
Is the check result normal?
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 Go to Step 2.
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 Repair the defective connector.
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STEP 2. Measure the output wave pattern of the high clutch and reverse
brake solenoid valve at CVT-ECU connector (HRLS terminal).
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(1)Connect the CVT assembly connector.
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(2)Selector lever position: D range.
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(3)Drive at a constant speed of approx. 20 km/h (auxiliary gearbox: at 1st
gear)
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(4)Connect an oscilloscope, and measure the voltage between CVT-ECU connector HRLS
terminal and body earth.
OK: A wave pattern such as the one shown on  (Check
Procedure Using an Oscilloscope) should be output, and the maximum value should be 11 V or more
and the minimum value should be 1 V or less. There should be no noise in the output wave pattern.
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Q.
Is the check result normal?
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Go to Step 3.
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Refer to diagnosis code No.P0976: High Clutch and Reverse Brake Solenoid Valve
(short to earth) , or diagnosis code No.P0977: High Clutch and Reverse
Brake Solenoid Valve (open circuit/
short to power supply) .
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STEP 3. Symptom recheck after erasing diagnosis code
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(1)Erase the diagnosis code.
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(2)Turn the ignition switch to the LOCK (OFF) position, and then wait for one minute.
Then drive the vehicle until the engine has been warmed up.
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(3)Check if the diagnosis code is stored.
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Q.
Is the diagnosis code stored?
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Replace the CVT assembly.
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Intermittent malfunction (Refer to GROUP 00 -
How to Cope with Intermittent
Malfunctions .).
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