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.
Transmission Control Switch Circuit: Procedure
- INSPECT TRANSMISSION CONTROL SWITCH
- Disconnect the H31 transmission control switch connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 3 (IG) - 7 (S) Shift lever in S, "+" and "-" Below 1 Ω 2 (SFTU) - 5 (E) Shift lever continuously in "+"
(Up-shift)Below 1 Ω 1 (SFTD) - 5 (E) Shift lever continuously in "-"
(Down-shift)Below 1 Ω 3 (IG) - 7 (S) Shift lever not in S, "+" and "-" 10 kΩ or higher 2 (SFTU) - 5 (E) Shift lever in S 10 kΩ or higher 1 (SFTD) - 5 (E) Shift lever in S 10 kΩ or higher
NG → See step 5
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BATTERY, BODY GROUND)
- Disconnect the H31 transmission control switch connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition H31-3 (IG) - Body ground Ignition switch ON 11 to 14 V Ignition switch off Below 1 V - Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition H31-5 (E) - Body ground Always Below 1 Ω
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM)
- Disconnect the A27 ECM connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition A27-25 (S) - Body ground - Ignition switch ON
- Shift lever in S, "+" and "-"
11 to 14 V - Ignition switch ON
- Shift lever not in S, "+" and "-"
Below 1 V - Turn the ignition switch off.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A27-38 (SFTU) - Body ground Shift lever continuously in "+"
(Up-shift)Below 1 Ω A27-27 (SFTD) - Body ground Shift lever continuously in "-"
(Down-shift)Below 1 Ω A27-38 (SFTU) - Body ground Shift lever in S 10 kΩ or higher A27-27 (SFTD) - Body ground Shift lever in S 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 4
- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE
- REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (TRANSMISSION CONTROL SWITCH). Refer to REMOVAL
NO RELATED
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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.