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.
DTC P1626: Auto Start Request Circuit High: Notes
1. -
DTC detecting condition:
Detected when three consecutive driving cycles with fault occur.
Trouble symptom:
Auto Start Stop does not operate.
Wiring diagram:
- ENGINE TYPE FB
Auto Start Stop Ref. to WIRING SYSTEM>AUTO START STOP>WIRING DIAGRAM>ENGINE TYPE FB .
- ENGINE TYPE FA
Auto Start Stop Ref. to WIRING SYSTEM>AUTO START STOP>WIRING DIAGRAM>ENGINE TYPE FA .
- Use the check board when measuring the TCM/ECM terminal voltage and resistance.
- After servicing or replacing faulty parts, perform the last step of the basic diagnostic procedure. Ref. to AUTO START STOP (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE .
- CHECK DATA MONITOR
.
- Turn the ignition switch to ON.
- Read the data of [Restart Commanded Signal] in ECM using Subaru Select Monitor. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>DATA MONITOR . Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>DATA MONITOR .
NOTE:Start the engine and drive at 5 km/h (3 MPH) or more.
Does the display of [Restart Commanded Signal] change to [ON] while driving?
Yes: The circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.
NOTE:In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
No: Go to 2 .
- CHECK HARNESS BETWEEN ECM CONNECTOR AND TCM CONNECTOR
.
- Turn the ignition switch to OFF.
- Disconnect the ECM connector.
- Disconnect the TCM connector.
- Measure the resistance between ECM connector and TCM connector.
Connector and terminal
ENGINE TYPE FB
(E53) No. 36 - (T21) No. 23:
ENGINE TYPE FA
(E51) No. 19 - (B67) No. 23:
Is the resistance less than 1 Ω?
Yes: Go to 3 .
No: Repair the open circuit of harness and poor contact of coupling connector between ECM connector and TCM connector.
- CHECK DATA MONITOR
.
- Connect the ECM connector.
- Turn the ignition switch to ON.
- Read the data of [Restart Commanded Signal] in ECM using Subaru Select Monitor. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>DATA MONITOR . Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>DATA MONITOR .
- Short the terminal No. 23 of TCM connector to ground.
Does the display of [Restart Commanded Signal] change to [ON]?
Yes: Check for poor contact of ECM connector. Replace the ECM if no fault is found. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) . Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM) .
No: Check for poor contact of TCM connector. Replace the TCM if no fault is found. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>TRANSMISSION CONTROL MODULE (TCM) . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION CONTROL MODULE (TCM) .
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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.
