K120 / K121 (CVT): K120 CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM: P08C37F,P091400; Pressure Control Solenoid "M" Actuator Stuck Off; 2023 - 2025 MY Corolla Corolla Hatchback [09/2022

Last Modified: 07-31-2024	6.11:8.1.0	Doc ID: RM1000000025YNF
Model Year Start: 2023	Model: Corolla Hatchback	Prod Date Range: [09/2022 - ]
Title: K120 / K121 (CVT): K120 CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM: P08C37F,P091400; Pressure Control Solenoid "M" Actuator Stuck Off; 2023 - 2025 MY Corolla Corolla Hatchback [09/2022 - ]

DTC

P08C37F

Pressure Control Solenoid "M" Actuator Stuck Off

DTC

P091400

Gear Shift Position Circuit Range/Performance

DESCRIPTION

Using the current from the TCM, the shift solenoid valve SLG controls the B1 brake when the shift lever is in R, and controls the S1 synchronizer when the shift lever is in P, N, D, M*1 or B*2.

When the TCM requests the shift mode to be changed to gear mode, the S1 synchronizer is engaged and input torque is transferred to the 1st gear.

When the TCM requests the shift mode to be changed to belt mode and certain conditions are met, the S1 synchronizer is released and input torque is not transferred to the 1st gear.

The shift stroke sensor detects the S1 synchronizer position using the magnet on the shift fork, and sends signals to the TCM.

*1: w/ Sequential Shift

*2: w/o Sequential Shift

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P08C37F

Pressure Control Solenoid "M" Actuator Stuck Off

Any of the following conditions are met (2-trip detection logic):

When the TCM commands the S1 synchronizer to be engaged, the shift stroke sensor output value is less than 9.205 mm (0.362 in.) for 4 seconds or more.
When the TCM commands the S1 synchronizer to be released, the shift stroke sensor output value is 9.205 mm (0.362 in.) or more for 3 seconds or more.
When the TCM commands the S1 synchronizer to be released, the shift stroke sensor output value is 1.498 mm (0.0590 in.) or more for 8 seconds or more.

Transmission valve body assembly (shift solenoid valve SLG)
Continuously variable transaxle assembly

Comes on

DTC stored

SAE Code:

P08C4

P091400

Gear Shift Position Circuit Range/Performance

Any of the following conditions are met (2-trip detection logic):

When the TCM commands the S1 synchronizer to be engaged, the shift stroke sensor output value is less than 9.205 mm (0.362 in.) for 4 seconds or more.
When the TCM commands the S1 synchronizer to be released, the shift stroke sensor output value is 9.205 mm (0.362 in.) or more for 3 seconds or more.
When the TCM commands the S1 synchronizer to be released, the shift stroke sensor output value is 1.498 mm (0.0590 in.) or more for 8 seconds or more.

Shift stroke sensor
Continuously variable transaxle assembly

Comes on

DTC stored

SAE Code:

P0915

DTC Detection Condition Patterns (P08C37F and P091400):

		Vehicle Condition
		Pattern 1	Pattern 2	Pattern 3
Diagnostic Condition	TCM commands the S1 synchronizer to be engaged	○	-	-
Diagnostic Condition	TCM commands the S1 synchronizer to be released	-	○	○
Malfunction Condition	The shift stroke sensor output value is less than 9.205 mm (0.362 in.)	○	-	-
	The shift stroke sensor output value is 9.205 mm (0.362 in.) or more	-	○	-
	The shift stroke sensor output value is 1.498 mm (0.0590 in.) or more	-	-	○
Duration		4 seconds or more	3 seconds or more	8 seconds or more
Detection Logic		2-trip detection logic	2-trip detection logic	2-trip detection logic

HINT:

These DTCs are stored when any of the above detection patterns is met.

MONITOR DESCRIPTION

With the shift lever in P, N, D, M*1 or B*2, the shift solenoid valve SLG controls the S1 synchronizer and moves it to the requested position according to the requested shift mode.

When the TCM detects that the S1 synchronizer is not in the appropriate position, it determines that the shift solenoid valve SLG or shift stroke sensor is malfunctioning, illuminates the MIL and stores a DTC.

*1: w/ Sequential Shift

*2: w/o Sequential Shift

MONITOR STRATEGY

*: at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)
Related DTCs	P08C4: Pressure control solenoid "M" (Shift solenoid valve SLG)/Functional check P0915: Gear shift position (SFV)/Rationality fault diagnostics
Required sensors/Components	Crankshaft position sensor Transmission revolution sensor (NC1) Transmission revolution sensor (NOUT) CVT fluid temperature sensor Engine coolant temperature sensor Oil pressure sensor Shift solenoid valve SL1 Shift solenoid valve SL2 Shift solenoid valve SLP Shift solenoid valve SLS Shift solenoid valve SLG
Frequency of operation	Continuous
Duration	P08C4: OFF malfunction (A): 4 sec. OFF malfunction (B): 2 sec. ON malfunction (A): 3 sec. ON malfunction (B): 3 sec. ON malfunction (C): 8 sec.* P0915: OFF malfunction (A): 4 sec. OFF malfunction (B): 2 sec. ON malfunction (A): 3 sec. ON malfunction (B): 3 sec. ON malfunction (C): 8 sec.*
MIL operation	2 driving cycles
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

All

ETC system

(Electronic throttle control system)

Not system down

(MIL illuminated by following codes: P0121, P0122, P0123, P0222, P0223, P0604, P0606, P0607, P060D, P060E, P0657, P0658, P1607, P16B0, P2102, P2103, P2111, P2112, P2119, P2135)

KCS sensor circuit

(Knock sensor)

Not circuit malfunction

(MIL illuminated by following codes: P0327, P0328)

ECT sensor circuit

(Engine coolant temperature sensor)

Not circuit malfunction

(MIL illuminated by following codes: P0117, P0118)

IAT sensor circuit

(Intake air temperature sensor)

Not circuit malfunction

(MIL illuminated by following codes: P0112, P0113)

Crankshaft position sensor "A" circuit

(Crankshaft position sensor)

Not circuit malfunction

(MIL illuminated by following codes: P0335, P0337, P0338)

CAN communication between ECM and TCM

Not system down

(MIL illuminated by following codes: U0100, U0101)

Low voltage flag

OFF

Pressure control solenoid "K" circuit

(Shift solenoid valve SLS)

Not circuit malfunction

(MIL illuminated by following codes: P282F, P2830)

Pressure Control Solenoid "M" circuit

(Shift solenoid valve SLG)

Not circuit malfunction

(MIL illuminated by following codes: P08CA, P08CB)

Transmission fluid temperature sensor "A" circuit

(CVT fluid temperature sensor)

Not circuit malfunction

(MIL illuminated by following codes: P0712, P0713)

Turbine speed sensor "A" circuit

(Transmission revolution sensor (NT))

Not circuit malfunction

(MIL illuminated by following codes: P0717, P07BF, P07C0)

Intermediate shaft speed sensor "C" circuit

(Transmission revolution sensor (NSS))

Not circuit malfunction

(MIL illuminated by following codes: P07C9, P07CA, P2751)

Gear shift position circuit

Not circuit malfunction

(MIL illuminated by following codes: P0916, P0917)

Output speed sensor circuit

(Transmission revolution sensor (NOUT))

Not circuit malfunction

(MIL illuminated by following codes: P0722, P077C, P077D)

Intermediate shaft speed sensor "B" circuit

(Transmission revolution sensor (NC1))

Not circuit malfunction

(MIL illuminated by following codes: P07C7, P07C8, P2747)

P08C4:

OFF malfunction (A)

Shift position	"N" or "P" or "D" or "B"
Shift solenoid valve SLP	Operating shift control by TCM command
Engine speed	500 rpm or more

OFF malfunction (B)

Engine speed	550 rpm or more
Transmission fluid temperature	-10°C (14°F) or more
Time after following condition is met	0.5 sec. or more
- Variation of the accelerator pedal angle (within 32.768 msec.)	Less than 0.5%
Shift solenoid valve SLS	Operating clamping pressure control by TCM command
ECT	60°C (140°F) or more
Spark advance from MAX. retard timing by KCS control	0 °CA or more
Gear and belt mode clutch	Either engagement or disengagement

ON malfunction (A)

Shift position	"N" or "P" or "D" or "B"
Gear mode clutch	Released
Reverse clutch	Released
Shift solenoid valve SLP	Operating shift control by TCM command
Shift solenoid valve SLG	Operating synchronizer control by TCM command
Engine speed	500 rpm or more
Any of the following conditions are met: (a) or (b)	-
(a) Gear mode clutch speed	Less than 4500 rpm
(b) Time after following condition is met at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)	60 sec. or more
- Engine speed	400 rpm or more

ON malfunction (B)

*It is calculated, when TCM switch indicate from synchronizer engaged to release
Shift position	"N" or "P" or "D" or "B"
Gear mode clutch	Released
Reverse clutch	Released
Shift solenoid valve SLP	Operating shift control by TCM command
Shift solenoid valve SLG	Operating synchronizer control by TCM command
Engine speed	500 rpm or more
Any of the following conditions are met: (a) or (b)	-
(a) Gear mode clutch speed	Less than 4500 rpm
(b) Time after following condition is met at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)	60 sec. or more
- Engine speed	400 rpm or more
Belt mode clutch	Engaged
Synchronizer output speed - Synchronizer input speed*	100 rpm or more
Output speed	500 rpm or more

ON malfunction (C)

Shift position	"N" or "P" or "D" or "B"
Gear mode clutch	Released
Reverse clutch	Released
Shift solenoid valve SLP	Operating shift control by TCM command
Shift solenoid valve SLG	Operating synchronizer control by TCM command
Engine speed	500 rpm or more
Any of the following conditions are met: (a) or (b)	-
(a) Gear mode clutch speed	Less than 4500 rpm
(b) Time after following condition is met at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)	60 sec. or more
- Engine speed	400 rpm or more

P0915:

OFF malfunction (A)

Shift position	"N" or "P" or "D" or "B"
Shift solenoid valve SLP	Operating shift control by TCM command
Engine speed	500 rpm or more

OFF malfunction (B)

Engine speed	550 rpm or more
Transmission fluid temperature	-10°C (14°F) or more
Time after following condition is met	0.5 sec. or more
- Variation of the accelerator pedal angle (within 32.768 msec.)	Less than 0.5%
Shift solenoid valve SLS	Operating clamping pressure control by TCM command
ECT	60°C (140°F) or more
Spark advance from MAX. retard timing by KCS control	0 °CA or more
Gear and belt mode clutch	Either engagement or disengagement

ON malfunction (A)

Shift position	"N" or "P" or "D" or "B"
Gear mode clutch	Released
Reverse clutch	Released
Shift solenoid valve SLP	Operating shift control by TCM command
Shift solenoid valve SLG	Operating synchronizer control by TCM command
Engine speed	500 rpm or more
Any of the following conditions are met: (a) or (b)	-
(a) Gear mode clutch speed	Less than 4500 rpm
(b) Time after following condition is met at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)	60 sec. or more
- Engine speed	400 rpm or more

ON malfunction (B)

Shift position	"N" or "P" or "D" or "B"
Gear mode clutch	Released
Reverse clutch	Released
Shift solenoid valve SLP	Operating shift control by TCM command
Shift solenoid valve SLG	Operating synchronizer control by TCM command
Engine speed	500 rpm or more
Any of the following conditions are met: (a) or (b)	-
(a) Gear mode clutch speed	Less than 4500 rpm
(b) Time after following condition is met at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)	60 sec. or more
- Engine speed	400 rpm or more

ON malfunction (C)

Shift position	"N" or "P" or "D" or "B"
Gear mode clutch	Released
Reverse clutch	Released
Shift solenoid valve SLP	Operating shift control by TCM command
Shift solenoid valve SLG	Operating synchronizer control by TCM command
Engine speed	500 rpm or more
Any of the following conditions are met: (a) or (b)	-
(a) Gear mode clutch speed	Less than 4500 rpm
(b) Time after following condition is met at CVT fluid temperature 80°C (176°F) (Conditions vary with CVT fluid temperature)	60 sec. or more
- Engine speed	400 rpm or more

TYPICAL MALFUNCTION THRESHOLDS

P08C4:

OFF malfunction

All of the following conditions are met

OFF malfunction (A)

TCM indicate synchronizer	Engagement
Synchronizer	Not engaged

OFF malfunction (B) (after OFF malfunction (A) is met)

Target clamping pressure	1.4 MPa (14.3 kgf/cm², 203 psi) or more
Actual clamping pressure - Target clamping pressure	Less than 0.5 MPa (5.1 kgf/cm², 73 psi)

ON malfunction

ON malfunction (A) and (B) are met or ON malfunction (C) is met

ON malfunction (A)

TCM indicate synchronizer	Release
Synchronizer	Engaged

ON malfunction (B) (after ON malfunction (A) is met)

Synchronizer input speed - Synchronizer output speed

Less than 100 rpm

ON malfunction (C)

TCM indicate synchronizer	Release
Synchronizer	Not released

P0915:

OFF malfunction

All of the following conditions are met

OFF malfunction (A)

TCM indicate synchronizer	Engagement
Synchronizer	Not engaged

OFF malfunction (B) (after OFF malfunction (A) is met)

Target clamping pressure	1.4 MPa (14.3 kgf/cm², 203 psi) or more
Actual clamping pressure - Target clamping pressure	Less than 0.5 MPa (5.1 kgf/cm², 73 psi)

ON malfunction

ON malfunction (A) and (B) are met or ON malfunction (C) is met

ON malfunction (A)

TCM indicate synchronizer	Release
Synchronizer	Engaged

ON malfunction (B) (after ON malfunction (A) is met)

Synchronizer input speed - Synchronizer output speed

300 rpm or more

ON malfunction (C)

TCM indicate synchronizer	Release
Synchronizer	Not released

CONFIRMATION DRIVING PATTERN

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
When clearing the permanent DTCs, refer to the Clear Permanent DTC procedure.
Click here

Connect the Techstream to the DLC3.
Turn the engine switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for 2 minutes or more.
Turn the engine switch on (IG) and turn the Techstream on.
Start the engine.
Perform the D Position Shift Test inspection in Road Test. [*1]
Click here

HINT:

[*1]: Normal judgment procedure.

The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
Stop the vehicle.
Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
Input the DTC: P08C37F or P091400.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, perform the normal judgment procedure again.

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs.
Click here
Perform registration and/or initialization when parts related to the continuously variable transaxle system are replaced.
Click here
Check that no DTCs are stored after performing initialization.
Click here

HINT:

If any DTCs other than P08C37F or P091400 are output, perform troubleshooting for those DTCs first.

PROCEDURE

1.	CHECK DTC OUTPUT (IN ADDITION TO DTC P08C37F AND P091400)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(d) Enter the following menus: Powertrain / Transmission / Trouble Codes.

Powertrain > Transmission > Trouble Codes

(e) Read the DTCs using the Techstream.

HINT:

If DTC P08C312 or P08C314 is output, perform troubleshooting for that DTC first.
If DTCs P08C312 and P08C314 are not output but DTC P091412 or P091414 is output, perform troubleshooting for DTC P091412 or P091414 first.

Result	Proceed to
Only DTC P08C37F and/or P091400 is output	A
DTC P08C37F and/or P091400 and P08C312 are output	B
DTC P08C37F and/or P091400 and P08C314 are output	C
DTC P08C37F and/or P091400 and P091412 are output	D
DTC P08C37F and/or P091400 and P091414 are output	E
DTC P08C37F and/or P091400 and DTCs other than P08C312, P08C314, P091412 and P091414 are output	F

GO TO DTC CHART (DTC P08C312)

GO TO DTC CHART (DTC P08C314)

GO TO DTC CHART (DTC P091412)

GO TO DTC CHART (DTC P091414)

GO TO DTC CHART

2.	INSPECT SHIFT STROKE SENSOR

Click here

REPLACE SHIFT STROKE SENSOR

3.	INSPECT TRANSMISSION VALVE BODY ASSEMBLY (SHIFT SOLENOID VALVE SLG)

(a) Disconnect the transmission wire connector from the shift solenoid valve SLG.

Click here

Transmission Valve Body Assembly

Shift Solenoid Valve SLG

Component without harness connected

(Shift Solenoid Valve SLG)

(b) Connect a positive (+) lead from the battery with a 21 W bulb to terminal 1 and a negative (-) lead to terminal 2 of the shift solenoid valve SLG connector. Check that the valve moves and makes an operating sound.

OK:

Valve moves and makes an operating sound.

GO TO STEP 5

4.	REPLACE CONTINUOUSLY VARIABLE TRANSAXLE ASSEMBLY

(a) Replace the continuously variable transaxle assembly.

Click here

PERFORM REGISTRATION AND INITIALIZATION

for Registration: Click here

for Initialization: Click here

5.	REPLACE TRANSMISSION VALVE BODY ASSEMBLY

(a) Replace the transmission valve body assembly.

Click here

PERFORM REGISTRATION AND INITIALIZATION

for Registration: Click here

for Initialization: Click here