STOP AND START: STOP AND START SYSTEM: P161D9E; Starter Delay Circuit Stuck On; 2019 - 2021 MY RAV4 [11/2018

Last Modified: 01-30-2024	6.11:8.1.0	Doc ID: RM100000001EEKE
Model Year Start: 2019	Model: RAV4	Prod Date Range: [11/2018 - 12/2021]
Title: STOP AND START: STOP AND START SYSTEM: P161D9E; Starter Delay Circuit Stuck On; 2019 - 2021 MY RAV4 [11/2018 - 12/2021]

DTC

P161D9E

Starter Delay Circuit Stuck On

DESCRIPTION

By using the starter delay circuit, the engine stop and start ECU can activate the ST NO. 2 relay (for starter motor operation) after activating the ST NO. 1 relay (for starter pinion operation) to operate the starter assembly.

By monitoring the condition of the ST NO. 1 relay (for starter pinion operation) and ST NO. 2 relay (for starter motor operation), the engine stop and start ECU detects if the transistor of the starter delay circuit is stuck. If the transistor of the starter delay circuit is stuck on, the engine stop and start ECU blinks the stop and start cancel indicator and stores DTC P161D9E. If the transistor of the starter delay circuit is stuck on, the ST NO. 1 relay (for starter pinion operation) and ST NO. 2 relay (for starter motor operation) will be activated simultaneously.

w/ Smart Key System

w/o Smart Key System

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Warning Indicate	Memory	Note
P161D9E	Starter Delay Circuit Stuck On	Both of the following conditions are met (1 trip detection logic): Ignition switch ON. Time between ST NO. 1 relay (for starter pinion) turning on and ST NO. 2 relay (for starter motor) turning on becomes less than 0.016 seconds and 3 times or more.	Engine stop and start ECU	Blinks	DTC stored	SAE Code: P161D

CONFIRMATION DRIVING PATTERN

CONFIRMATION AFTER TROUBLESHOOTING

HINT:

If the cable is disconnected from the battery terminal, stop and start control is prohibited until refresh charge is completed.
In this case, let the vehicle idle to complete the refresh charge. The refresh charge is complete when the Data List item "Status of Battery Charge Control" changes from "Refresh Charge Mode". (Usually, idling the engine for 5 to 60 minutes with the battery fluid temperature at 11°C (51°F) or higher, the refresh charge will be completed.)
If the Techstream is not available and the Data List item "Status of Battery Charge Control" cannot be checked, charge the battery by idling the engine for approximately 5 to 60 minutes or driving the vehicle, and then drive the vehicle and check that stop and start control operates.
If the engine is started with the hood open, the system determines that a jump start has occurred. Therefore, make sure that the hood is closed before starting the engine and driving the vehicle.
After the refresh charge completes, turn the ignition switch off, wait for at least 30 seconds, and then start the engine again. If the vehicle enters refresh charge mode again while the engine is idling, the initial refresh charge did not properly complete, so wait for the refresh charge to complete.
Allow the engine to idle for 3 minutes after it is warmed up and check that the engine idle speed is within 50 rpm of the target idle speed.

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Clear the DTCs.

Powertrain > Stop and Start > Clear DTCs

(e) Start the engine and warm it up.

(f) Drive the vehicle at 7 km/h (4 mph) or more.

CAUTION:

When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

(g) Depress the brake pedal and stop the vehicle.

(h) Keep the engine stopped by stop and start control. (Keep the shift lever in D.)

(i) Release the brake pedal with the shift lever in D to start the engine.

(j) Drive the vehicle at 7 km/h (4 mph) or more.

CAUTION:

When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

(k) Depress the brake pedal and stop the vehicle.

(l) Keep the engine stopped by stop and start control. (Keep the shift lever in D.)

(m) Release the brake pedal with the shift lever in D to start the engine.

(n) Drive the vehicle at 7 km/h (4 mph) or more.

CAUTION:

When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

(o) Depress the brake pedal and stop the vehicle.

(p) Keep the engine stopped by stop and start control. (Keep the shift lever in D.)

(q) Release the brake pedal with the shift lever in D to start the engine.

(r) Check that no DTCs are output.

Powertrain > Stop and Start > Trouble Codes

STOP AND START SYSTEM OPERATION CHECK

HINT:

If the cable is disconnected from the battery terminal, stop and start control is prohibited until refresh charge is completed.
In this case, let the vehicle idle to complete the refresh charge. The refresh charge is complete when the Data List item "Status of Battery Charge Control" changes from "Refresh Charge Mode". (Usually, idling the engine for 5 to 60 minutes with the battery fluid temperature at 11°C (51°F) or higher, the refresh charge will be completed.)
If the Techstream is not available and the Data List item "Status of Battery Charge Control" cannot be checked, charge the battery by idling the engine for approximately 5 to 60 minutes or driving the vehicle, and then drive the vehicle and check that stop and start control operates.
If the engine is started with the hood open, the system determines that a jump start has occurred. Therefore, make sure that the hood is closed before starting the engine and driving the vehicle.
After the refresh charge completes, turn the ignition switch off, wait for at least 30 seconds, and then start the engine again. If the vehicle enters refresh charge mode again while the engine is idling, the initial refresh charge did not properly complete, so wait for the refresh charge to complete.

(a) Start the engine and warm it up.

(b) Turn the air conditioning system off.

CAUTION:

When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

(d) Depress the brake pedal and stop the vehicle.

(e) Allow the engine to stop by stop and start control. (Keep the shift lever in D.)

(f) Release the brake pedal with the shift lever in D to start the engine.

WIRING DIAGRAM

Refer to DTC P061519.

Click here

CAUTION / NOTICE / HINT

NOTICE:

Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU.
Click here
After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU.
Click here
After replacing the engine stop and start ECU or airbag ECU assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.
Click here
When the engine stop and start ECU or oil pump with solenoid assembly is replaced, check the oil pump with solenoid assembly.
Click here

HINT:

Using the Techstream, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting.
Click here
DTCs for the stop and start system are not cleared even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.
Click here

PROCEDURE

1.	CHECK ENGINE STOP AND START ECU (STA, STA2 SIGNAL)

(a) Connect an oscilloscope to the STA, STA2 and DGND terminals of the stop and start ECU connector.

Component with harness connected

(Engine Stop and Start ECU)

(b) Check the waveform immediately after turning the ignition switch START.

Item

Condition

Tester Connection

A34-21 (STA) - A34-6 (DGND)

A34-23 (STA2) - A34-6 (DGND)

Condition

Engine started by ignition switch operation

Result:

Result	Proceed to
Time between ST NO. 1 relay (for starter pinion) turning on and ST NO. 2 relay (for starter motor) turning on becomes 0.016 seconds or more	A
Time between ST NO. 1 relay (for starter pinion) turning on and ST NO. 2 relay (for starter motor) turning on becomes less than 0.016 seconds	B

USE SIMULATION METHOD TO CHECK

REPLACE ENGINE STOP AND START ECU