Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSTOYOTA2025COROLLA CROSS L, FWDREPAIR AND DIAGNOSIS (SINGLE PAGE)TRANSMISSIONAUTOMATIC TRANSAUTOMATIC TRANSAXLE SYSTEM (K121 / K121F) - DIAGNOSTICS - INTRODUCTIONCONTINUOUSLY VARIABLE TRANSAXLE SYSTEMHOW TO PROCEED WITH TROUBLESHOOTING [11/2023 - ]PROCEDURE

2025 Toyota Corolla Cross L, FWD

How To Proceed With Troubleshooting [11/2023 - ]: Procedure

2025 Toyota Corolla Cross L, FWDSECTION Procedure

VEHICLE BROUGHT TO WORKSHOP
Result

Proceed to

NEXT

Result:

NEXT

See step 2
CUSTOMER PROBLEM ANALYSIS
Refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2021 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 3

INSPECT BATTERY VOLTAGE

Measure the battery voltage.

Standard Voltage

11 to 14 V

HINT:

If the voltage is below 11 V, recharge or replace the battery before proceeding to the next step.

Result

Proceed to
NEXT

Result:

See step 4

CHECK CAN COMMUNICATION SYSTEM*

Using the GTS, check if the CAN communication system is functioning normally.

CAN Bus Check

CAN communication system is functioning normally.

HINT:

Refer to CAN Bus Check in CAN Communication System.
Refer to DIAGNOSIS SYSTEM [11/2023 - 12/2024] , or refer to DIAGNOSIS SYSTEM [12/2024 - ]
The ECM is connected to the CAN communication system. Therefore, before starting troubleshooting, make sure to check that there are no malfunctions in the CAN communications system.

Result

Proceed to
OK
NG

Result:

GO TO CAN COMMUNICATION SYSTEM

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2023 - 12/2024] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2024 - ]

Result:

See step 5

CHECK AND CLEAR DTCS AND FREEZE FRAME DATA*

Refer to DTC Check/Clear.

Refer to DTC CHECK / CLEAR [11/2023 - ]

Result

Proceed to
NEXT

Result:

See step 6

SELECT CHECK MODE DIAGNOSIS*

Refer to Check Mode Procedure.

Refer to CHECK MODE PROCEDURE [11/2023 - ]

Result

Proceed to
NEXT

Result:

See step 7

CHECK FOR DTC*

Proceed to DTC Check/Clear.

Refer to DTC CHECK / CLEAR [11/2023 - ]

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B

Result:

See step 14

Result:

See step 8

BASIC INSPECTION

Refer to Continuously Variable Transaxle Fluid.
Refer to ADJUSTMENT [11/2023 - ]

Refer to Shift Lever.

Refer to ON-VEHICLE INSPECTION [11/2023 - ]

Result

Proceed to
OK
NG

Result:

See step 11

Result:

See step 9

PROBLEM SYMPTOMS CONFIRMATION

Refer to Road Test.
Refer to ROAD TEST [11/2023 - ]
Refer to Mechanical System Tests.
Refer to MECHANICAL SYSTEM TESTS [11/2023 - ]

Refer to Hydraulic Test.

Refer to HYDRAULIC TEST [11/2023 - ]

Result

Result	Proceed to
Symptom does not occur	A
Symptom occurs	B

Result:

See step 11

Result:

See step 10

SYMPTOM SIMULATION

Refer to Symptom Simulation.

Refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2021 - ]

Result

Proceed to
NEXT

Result:

See step 11

COMPONENT INSPECTION
Result

Proceed to

NEXT

Result:

NEXT

See step 12
REPAIR OR REPLACE
Result

Proceed to

NEXT

Result:

NEXT

See step 13
CONFIRMATION TEST
Result

Proceed to

NEXT

Result:

NEXT

END

DIAGNOSTIC TROUBLE CODE CHART

Proceed to Diagnostic Trouble Code Chart.

Refer to DIAGNOSTIC TROUBLE CODE CHART [11/2023 - ]

Result

Proceed to
NEXT

Result:

See step 15

CIRCUIT INSPECTION
Result

Proceed to

NEXT

Result:

NEXT

See step 16
IDENTIFICATION OF PROBLEM
Result

Proceed to

NEXT

Result:

NEXT

See step 17
REPAIR OR REPLACE
Result

Proceed to

NEXT

Result:

NEXT

See step 18
CONFIRMATION TEST
Result

Proceed to

NEXT

Result:

NEXT

END

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.