Lexus NX: Drive Start Control System

DESCRIPTION

The drive start control is controlled by the hybrid vehicle control ECU.

If the hybrid vehicle control ECU determines that the shift lever and accelerator pedal are operated abnormally, driving torque is restricted and, when necessary, a warning is displayed on the combination meter assembly.

CAUTION / NOTICE / HINT

HINT:

Even if the accelerator pedal position is maintained, the engine output may increase when driving uphill and decrease when driving downhill. This is due to the drive start control controlling the driving torque, and is not a malfunction.

PROCEDURE

1.

SYMPTOM CONFIRMATION

(a) Interview the customer to confirm the problem.

Hesitation/poor acceleration

GO TO STEP 8

Hunting

2.

PAST ACTIVATION CONFIRMATION

(a) Check if the customer operated the vehicle in a way that would cause the drive start control to operate.

Drive Start Control Activation Conditions

HINT:

Condition 1 (Reverse control)

Activation conditions

  • The shift lever is in R.
  • The accelerator pedal is depressed.

Items Controlled

  • Driving torque is restricted.

Deactivation Conditions

  • The shift lever is moved to any position other than R.
  • The accelerator pedal is released.

Condition 2 (Shift control a)

Activation conditions

  • The shift lever is moved from P to any forward position (D or S) or R.
  • The accelerator pedal is open by approximately 1/5 or more.

Items Controlled

  • Driving torque is restricted.

Deactivation Conditions

  • The shift lever is in P or N.
  • The accelerator pedal is released.

Condition 3 (Shift control b)

Activation conditions

  • The shift lever is moved from R to any forward position (D or S), any forward position (D or S) to R, or N to R.
  • The accelerator pedal is open by approximately 1/5 or more.

Items Controlled

  • Driving torque is restricted.

Deactivation Conditions

  • The shift lever is in P or N.
  • The accelerator pedal is released.

HINT:

During reverse control or shift control, driving torque is adjusted based on the road gradient and steering angle.

Not performed

SYSTEM NORMAL (GO TO PROBLEM SYMPTOM TABLE)

Performed

3.

CHECK DTC OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Enter the following menus: System Select / Health Check.

(d) Check the DTCs.

(e) Turn the power switch off.

DTC is output

GO TO DTC CHART

DTCs are not output

4.

READ VALUE USING TECHSTREAM (FR, FL, RR, RL WHEEL SPEED)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (READY).

(c) Enter the following menus: Chassis / ABS/VSC/TRC / Data List / FR Wheel Speed, FL Wheel Speed, RR Wheel Speed and RL Wheel Speed.

Chassis > ABS/VSC/TRC > Data List

Tester Display

FR Wheel Speed

FL Wheel Speed

RR Wheel Speed

RL Wheel Speed

Chassis > ABS/VSC/TRC > Data List

Tester Display

Measurement Item

Range

Normal Condition

FR Wheel Speed

Front speed sensor RH

Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph)

When driving at constant speed: No large fluctuations

FL Wheel Speed

Front speed sensor LH

Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph)

When driving at constant speed: No large fluctuations

RR Wheel Speed

Rear speed sensor RH

Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph)

When driving at constant speed: No large fluctuations

RL Wheel Speed

Rear speed sensor LH

Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph)

When driving at constant speed: No large fluctuations

(d) Read the value displayed on the Techstream.

Standard:

Techstream Display

Condition

Specified Condition

FR Wheel Speed

FL Wheel Speed

RR Wheel Speed

RL Wheel Speed

Vehicle stopped, engine running

0 km/h (0 mph)

Vehicle being driven at constant speed between 16.1 to 64.4 km/h (10 to 40 mph)

No large fluctuations when driving at a constant speed

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.

(e) Turn the power switch off.

NG

INSPECT FRONT OR REAR SPEED SENSOR

OK

5.

READ VALUE USING TECHSTREAM (VEHICLE SPD)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Enter the following menus: Powertrain / Hybrid Control / Data List / Vehicle Spd.

Powertrain > Hybrid Control > Data List

Tester Display

Vehicle Spd

(d) Read the value of "Vehicle Spd" displayed on the Techstream.

Standard:

Inspection Condition

Specified Condition

Vehicle stopped

0 km/h (0 mph)

Vehicle being driven at a constant speed

(16 to 64 km/h (10 to 40 mph))

No large fluctuations in displayed speed

CAUTION:

Perform this road test only in an appropriate safe location, in accordance with all local laws.

HINT:

Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.

(e) Turn the power switch off.

NG

INSPECT ELECTRONICALLY CONTROLLED BRAKE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

OK

6.

READ VALUE USING TECHSTREAM (DECELERATION SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (READY).

(c) Enter the following menus: Chassis / ABS/VSC/TRC / Data List / Deceleration Sensor and Deceleration Sensor2.

Chassis > ABS/VSC/TRC > Data List

Tester Display

Deceleration Sensor

Deceleration Sensor2

(d) Read the value displayed on the Techstream.

Standard:

Techstream Display

Condition

Specified Condition

Deceleration Sensor

Deceleration Sensor2

During deceleration

Value changes with vehicle speed

During acceleration

Value changes with vehicle speed

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.

(e) Turn the power switch off.

NG

INSPECT YAW RATE SENSOR

OK

7.

READ VALUE USING TECHSTREAM (STEERING ANGLE SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (READY).

(c) Enter the following menus: Chassis / ABS/VSC/TRC / Data List / Steering Angle Sensor.

Chassis > ABS/VSC/TRC > Data List

Tester Display

Steering Angle Sensor

Chassis > ABS/VSC/TRC > Data List

Tester Display

Measurement Item

Range

Normal Condition

Steering Angle Sensor

Steering angle sensor

Min.: -3276.8 degrees, Max.: 3276.7 degrees

Turning left: Increases

Turning right: Decreases

(d) Read the value displayed on the Techstream.

Standard:

Condition

Specified Condition

Steering wheel turned left

Value increases with steering wheel operation

Steering wheel turned right

Value decreases with steering wheel operation

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

Data can be captured relatively easily by using the snapshot function in the Data List. Confirm the data after performing the drive test.

(e) Turn the power switch off.

OK

SYSTEM NORMAL (GO TO PROBLEM SYMPTOM TABLE)

NG

INSPECT STEERING ANGLE SENSOR

8.

PAST ACTIVATION CONFIRMATION

(a) Check if the customer operated the vehicle in a way that would cause the drive start control to operate.

Drive Start Control Activation Conditions

HINT:

Condition 1 (Reverse control)

Activation conditions

  • The shift lever is in R.
  • The accelerator pedal is depressed.

Items Controlled

  • Driving torque is restricted.

Deactivation Conditions

  • The shift lever is moved to any position other than R.
  • The accelerator pedal is released.

Condition 2 (Shift control a)

Activation conditions

  • The shift lever is moved from P to any forward position (D, S or M) or R.
  • The accelerator pedal is open by approximately 1/5 or more.

Items Controlled

  • Driving torque is restricted.

Deactivation Conditions

  • The shift lever is in P or N.
  • The accelerator pedal is released.

Condition 3 (Shift control b)

Activation conditions

  • The shift lever is moved from R to any forward position (D, S or M), any forward position (D, S or M) to R, or N to R.
  • The accelerator pedal is open by approximately 1/5 or more.

Items Controlled

  • Driving torque is restricted.

Deactivation Conditions

  • The shift lever is in P or N.
  • The accelerator pedal is released.

HINT:

During reverse control or shift control, driving torque is adjusted based on the road gradient and steering angle.

Result

Proceed to

Not performed

A

Performed

B

HINT:

If the customer operated the vehicle in a way which caused the drive start control to operate, explain the operation of the system to the customer and that the operation is not a malfunction.

B

SYSTEM NORMAL

A

9.

CHECK DTC OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: System Select / Health Check.

(e) Check the DTCs.

Result

Proceed to

DTCs are not output

A

DTC is output

B

B

GO TO DTC CHART

A

10.

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

(a) Inspect the park/neutral position switch assembly.

Click here

Result

Proceed to

Normal

A

Abnormal

B

B

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY

A

11.

READ VALUE USING TECHSTREAM (ACCELERATOR PEDAL POSITION SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Hybrid Control / Data List / Accel Pedal Pos.

Powertrain > Hybrid Control > Data List

Tester Display

Accel Pedal Pos #1

Accel Pedal Pos #2

Powertrain > Hybrid Control > Data List

Tester Display

Measurement Item

Range

Normal Condition

Accel Pedal Pos #1

Accelerator pedal position sensor No. 1

(Sensor voltage is multiplied by 20 and displayed as a percentage)

-

Accelerator pedal depressed:

Changes with accelerator pedal pressure

Accel Pedal Pos #2

Accelerator pedal position sensor No. 2

(Sensor voltage is multiplied by 20 and displayed as a percentage)

-

Accelerator pedal depressed:

Changes with accelerator pedal pressure

(e) Read the value displayed on the Techstream.

OK:

Condition

Specified Condition

Accelerator Pedal Released → Depressed

Values smoothly change following accelerator pedal operation

(f) Turn the power switch off.

OK

SYSTEM NORMAL (GO TO PROBLEM SYMPTOM TABLE)

NG

REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY

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