DTC P1625: Auto Start Request Circuit Low: Notes

DTC detecting condition:

Detected when two 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 .

Courtesy of SUBARU OF AMERICA, INC.
ENGINE TYPE FA
Auto Start Stop Ref. to WIRING SYSTEM>AUTO START STOP>WIRING DIAGRAM>ENGINE TYPE FA .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Use the check board when measuring the 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 HARNESS BETWEEN ECM CONNECTOR AND TCM CONNECTOR .
1. Turn the ignition switch to OFF.
2. Disconnect the ECM connector.
3. Disconnect the TCM connector.
4. Measure the resistance between ECM connector and chassis ground.
  Connector & terminal
  
  ENGINE TYPE FB
  
  (E53) No. 36 - Chassis ground:
  
  ENGINE TYPE FA
  
  (E52) No. 20 - Chassis ground:
Is the resistance 1 MΩ or more?

Yes: Go to 2.

No: Repair the short circuit to ground in harness between ECM connector and TCM connector.
CHECK DATA MONITOR .
1. Connect the ECM connector.
2. Turn the ignition switch to ON.
3. 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 .
Is [OFF] displayed in [Restart Commanded Signal]?

Yes: Go to 3.

No: 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) .
CHECK DATA MONITOR .
1. Connect the TCM connector.
2. Turn the ignition switch to ON.
3. 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 .
Is [OFF] displayed in [Restart Commanded Signal]?

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: 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) .