DTC P1644-9E: Starter Circuit Stuck On [12/2019 - 10/2022]: Procedure

1. Read the DTCs.

   Powertrain > Stop and Start > Trouble Codes 

   Result

   Result	Proceed to
   DTC P1644-9E is output	A
   DTC P1644-9E and P060B-1C, P060B-49 or P060B-71 are output	B

   HINT: 

   If DTCs P1644-9E and P060B-1C, P060B-49 or P060B-71 are output simultaneously, troubleshoot for DTC P060B-1C, P060B-49 or P060B-71 first.

Result: 

B 

GO TO DTC P060B-1C, P060B-49 OR P060B-71. Refer to  DTC P060B-1C: Analog to Digital Converter Circuit Voltage Out of Range; DTC P060B-49: Analog to Digital Converter Internal Electronic Failure; DTC P060B-71: Analog to Digital Converter Actuator Stuck [12/2019 - 10/2022] 

Result: 

A 

See step  2

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the engine stop and start ECU connector.
2. Turn the ignition switch to ON.
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A34-1 (+B) - Body ground	Ignition switch ON	9.5 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE STOP AND START ECU - EFI-MAIN NO. 1 RELAY) 

Result: 

OK 

See step  3

1. Disconnect the engine stop and start ECU connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A34-6 (DGND) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ENGINE STOP AND START ECU. Refer to  REMOVAL [12/2019 - 10/2022] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR