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Home >> Subaru >> 2021 >> Ascent Base >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transaxle (Diagnostics) >> Transmission Control Module (TCM) I/O Signal >> Electrical Specification
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Electrical Specification

G13866525Courtesy of SUBARU OF AMERICA, INC.
CAUTION: Use the check board when measuring the TCM terminal.
NOTE: Measure after warming up.
Terminal No. Contents Measuring condition Standard Note
(B54) No. 1 ← → Chassis ground ATF temperature sensor GND Always 0 V -
(B54) No. 2 ← → Chassis ground Secondary pressure sensor GND Always 0 V -
(B54) No. 3 ← → Chassis ground Line pressure sensor GND Always 0 V -
(B54) No. 4 ← → (B54) No. 3 Line pressure sensor signal Ignition switch ON, engine OFF Approx. 0.5 V (0 MPa) Value increases with increase of engine load. (0.5 - 4.5 V)
Engine ON and idle Approx. 1.0 V (1.0 MPa)
(B54) No. 5 ← → (B54) No. 2 Secondary pressure sensor signal Ignition switch ON, engine OFF Approx. 0.5 V (0 MPa) Value increases with increase of engine load. (0.5 - 4.5 V)
Engine ON and idle Approx. 1.0 V (1.0 MPa)
(B54) No. 6 ← → (B54) No. 1 ATF temperature sensor signal ATF temperature at 20°C (68°F) Approx. 2.6 V Approx. 2.6 kΩ
ATF temperature at 80°C (176°F) Approx. 0.7 V Approx. 370 Ω
(B54) No. 8 ← → (B54) No. 26 or (B54) No. 42 Main power supply 3 Ignition switch ON Battery voltage -
(B54) No. 12 ← → (B54) No. 26 or (B54) No. 42 Front wheel speed sensor Engine ON, "P" or "N" range 0 or 5 V Refer to the waveform ("sensor") Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SENSOR .
(B54) No. 13 ← → (B54) No. 26 or (B54) No. 42 Secondary speed sensor While driving 0 or 5 V Refer to the waveform ("sensor") Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SENSOR .
(B54) No. 14 ← → (B54) No. 26 or (B54) No. 42 Primary speed sensor While driving 0 or 5 V Refer to the waveform (sensor) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SENSOR .
(B54) No. 15 ← → (B54) No. 26 or (B54) No. 42 Lock-up duty solenoid While driving in "D" range Refer to the waveform (solenoid (1)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 10 - 14.2 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
(B54) No. 16 ← → (B54) No. 26 or (B54) No. 42 F&R solenoid Engine ON, "P" range Refer to the waveform (solenoid (2)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 3.5 - 7.1 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
(B54) No. 17 ← → (B54) No. 3 Line pressure sensor power supply Ignition switch ON 5 V -
(B54) No. 18 ← →(B54) No. 26 or (B54) No. 42 Manual mode DOWN switch Ignition switch ON, Manual mode down switch ON 0 V -
Ignition switch ON, Manual mode down switch OFF Battery voltage
(B54) No. 19 ← →(B54) No. 26 or (B54) No. 42 Manual mode UP switch Ignition switch ON, Manual mode up switch ON 0 V -
Ignition switch ON, Manual mode up switch OFF Battery voltage
(B54) No. 20 ← →(B54) No. 26 or (B54) No. 42 Manual mode switch Ignition switch ON/Manual mode switch ON 0 V -
Ignition switch ON/Manual mode switch OFF Battery voltage
(B54) No. 24 ← →(B54) No. 26 or (B54) No. 42 Main power supply 2 Ignition switch ON Battery voltage -
(B54) No. 26 ← →Chassis ground GND Always 0 V -
(B54) No. 29 ← →(B54) No. 26 or (B54) No. 42 Stop light switch Stop light switch ON Battery voltage -
Stop light switch OFF 0 V
(B54) No. 30 ← →(B54) No. 26 or (B54) No. 42 Primary DOWN solenoid Engine ON, "P" range Refer to the waveform (solenoid (3)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 10 - 14.2 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
(B54) No. 31 ← →(B54) No. 26 or (B54) No. 42 Oil pump ON/OFF solenoid When oil pump is ON Refer to the waveform (solenoid (4)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 12.5 - 19.5 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
When oil pump is OFF Refer to the waveform (solenoid (5)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID .
(B54) No. 32 ← →(B54) No. 26 or (B54) No. 42 Line pressure solenoid Engine ON, "P" range Refer to the waveform (solenoid (6)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 3.3 - 7.3 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
(B54) No. 33 ← →(B54) No. 2 Secondary pressure sensor power supply Ignition switch ON 5 V -
(B54) No. 34 ← →(B54) No. 26 or (B54) No. 42 Backup power supply Always Battery voltage -
(B54) No. 35 ← →(B54) No. 26 or (B54) No. 42 D range switch Ignition switch ON, D range 0 V -
Ignition switch ON, other than D range Battery voltage
(B54) No. 36 ← →(B54) No. 26 or (B54) No. 42 N range switch Ignition switch ON, N range 0 V -
Ignition switch ON, other than N range Battery voltage
(B54) No. 37 ← →(B54) No. 26 or (B54) No. 42 R range switch Ignition switch ON, R range 0 V -
Ignition switch ON, other than R range Battery voltage
(B54) No. 38 ← →(B54) No. 26 or (B54) No. 42 P range switch Ignition switch ON, P range 0 V -
Ignition switch ON, other than P range Battery voltage
(B54) No. 40 ← →(B54) No. 26 or (B54) No. 42 Main power supply 1 Ignition switch ON Battery voltage -
(B54) No. 41 ← →(B54) No. 26 or (B54) No. 42 Ignition switch Ignition switch ON Battery voltage -
(B54) No. 42 ← →Chassis ground GND Always 0 V -
(B54) No. 43 CAN communication line (+) - - -
(B54) No. 44 CAN communication line (-) - - -
(B54) No. 46 ← →(B54) No. 26 or (B54) No. 42 Secondary solenoid Engine ON, "P" range Refer to the waveform (solenoid (6)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 3.3 - 7.3 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
(B54) No. 47 ← →(B54) No. 26 or (B54) No. 42 Primary UP solenoid Engine ON, "P" range Refer to the waveform (solenoid (7)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 10 - 14.2 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.
(B54) No. 48 ← →(B54) No. 26 or (B54) No. 42 AWD solenoid Engine ON, "D" range Refer to the waveform (solenoid (8)) Ref. to TRANSMISSION (DIAGNOSTICS)>Transmission Control Module (TCM) I/O Signal>WAVEFORM>SOLENOID . Resistance: Approx. 3.3 - 7.3 Ω
Resistance value at 20°C (68°F).
Value is higher as the temperature increase.