Lexus NX manuals

Lexus NX: Test Mode Procedure

Lexus NX Service Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System / Test Mode Procedure

TEST MODE PROCEDURE

WARNING LIGHT AND INDICATOR LIGHT INITIAL CHECK

(a) When the power switch is turned on (IG), check that the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction), slip indicator, brake hold standby indicator and brake hold operated indicator lights come on until the power switch is turned on (READY).

HINT:

  • When the brake fluid level is low, the brake warning light / red (malfunction) comes on.
  • When the power switch is turned on (IG), the VSC OFF indicator light comes on for approximately 3 seconds.
  • If the skid control ECU (brake booster with master cylinder assembly) stores any DTCs, the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights will come on. Also, in this state, if the vehicle is under the following conditions and the brake hold switch (integration control and panel assembly) is turned on, the brake hold operated indicator light blinks.
    • Vehicle Conditions:
      1. The driver's door is closed.
      2. Driver's seat belt is fastened.
  • If any of the indicators remains on or does not come on, proceed to troubleshooting for the light circuits listed below.

Trouble Area

See Procedure

ABS warning light circuit (Remains on)

ABS warning light circuit (Does not come on)

Brake warning light / red (malfunction) circuit (Remains on)

Brake warning light / red (malfunction) circuit (Does not come on)

Brake warning light / yellow (minor malfunction) circuit (Remains on)

Brake warning light / yellow (minor malfunction) circuit (Does not come on)

Slip indicator light circuit (Remains on)

Slip indicator light circuit (Does not come on)

Brake hold standby indicator light circuit

Brake hold operated indicator light circuit

SENSOR CHECK USING TEST MODE (SIGNAL CHECK)

NOTICE:

Before performing the master cylinder pressure sensor check, perform linear valve offset learning.

HINT:

  • If the power switch is turned from on (IG) to on (ACC) or off during Test Mode (signal check), DTCs recorded during the sensor check will be cleared.
  • During Test Mode (signal check), the skid control ECU (brake booster with master cylinder assembly) records all DTCs detected in the sensor check. By performing Test Mode (signal check), the codes are cleared as the normal condition for each item is confirmed. The remaining codes are the codes where an abnormality was found.
  • Even during Test Mode, if there is a system malfunction that causes brake hold control to be prohibited, when the vehicle is under the following conditions and the brake hold switch (integration control and panel assembly) is turned on, the brake hold operated indicator light blinks.
    • Vehicle Conditions:
      1. The driver's door is closed.
      2. Driver's seat belt is fastened.

(a) Procedure to Enter Test Mode

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

(2) Check that the steering wheel is centered.

(3) Check that the parking brake is released.

(4) Check that the shift lever is in P.

(5) Turn the power switch off.

(6) Connect the Techstream to the DLC3.

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

(8) Turn the Techstream on.

(9) Switch the skid control ECU (brake booster with master cylinder assembly) to Test Mode using the Techstream. Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / Signal Check.

Chassis > ABS/VSC/TRAC > Utility

Tester Display

Signal Check

(10) Check that the ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights come on for several seconds and then blink in the Test Mode pattern.

HINT:

If the ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights do not blink, inspect the ABS warning, brake warning / yellow (minor malfunction) and slip indicator light circuits.

(11) Check the ABS sensors.

HINT:

Check that the ABS warning light is blinking in the Test Mode pattern before performing the following ABS sensor checks.

(b) Acceleration Sensor Check

(1) Keep the vehicle stationary on a level surface for 2 seconds or more.

HINT:

The acceleration sensor check can be performed by following the master cylinder pressure sensor check procedure below.

(c) Master Cylinder Pressure Sensor Check

NOTICE:

Before performing the master cylinder pressure sensor check, perform linear valve offset learning.

(1) Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly and continuously depress the brake pedal with a force greater than 98 N (10 kgf, 22.0 lbf) for 1 second.

(2) Check that the ABS warning light remains on for 3 seconds.

HINT:

  • Confirm that the ABS warning light comes on.
  • While the ABS warning light remains on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22.0 lbf) or more.
  • The ABS warning light comes on for 3 seconds every time the preceding brake pedal operation is performed.

(d) Speed Sensor Check

NOTICE:

Before performing the speed sensor check, complete the acceleration sensor and master cylinder pressure sensor checks.

(1) Drive the vehicle straight-ahead.

Accelerate the vehicle to a speed of 45 km/h (28 mph) or more for several seconds and check that the ABS warning light goes off.

HINT:

  • The sensor check may not complete if wheelspin occurs.
  • The ABS warning light comes on immediately if a malfunction is detected during the speed sensor check.

(2) Stop the vehicle.

NOTICE:

  • The speed sensor check may not complete if the speed sensor check is started while turning the steering wheel or spinning the wheels.
  • After the ABS warning light goes off, if vehicle speed exceeds 80 km/h (50 mph), a sensor check code will be stored again. Decelerate or stop the vehicle before the speed reaches 80 km/h (50 mph).
  • If the sensor check has not completed, the ABS warning light will blink while the vehicle is being driven and the ABS will not operate.

(e) VSC OFF Switch (Integration Control and Panel Assembly) Check

(1) When Test Mode is activated, check that the VSC OFF indicator light in the combination meter assembly is turned off.

(2) Press the VSC OFF switch (integration control and panel assembly) and check that the VSC OFF indicator light in the combination meter assembly turns on.

(3) Press the VSC OFF switch (integration control and panel assembly) again and check that the VSC OFF indicator light in the combination meter assembly turns off.

(f) Brake Hold Switch (Integration Control and Panel Assembly) Check

HINT:

Perform the check with the system in a normal condition.

(1) Make sure the following conditions are met:

  • The driver side door is closed.
  • The driver side seat belt is fastened.

(2) Press the brake hold switch (integration control and panel assembly).

(3) Check that the brake hold standby indicator light is illuminated.

(4) Press the brake hold switch (integration control and panel assembly) again.

(5) Check that the brake hold standby indicator light turns off.

(g) End of Sensor Check

(1) When the sensor checks have completed, the ABS warning light goes off while the vehicle is being driven, and blinks in the Test Mode pattern while the vehicle is stopped.

NOTICE:

When the acceleration sensor, speed sensor and master cylinder pressure sensor checks complete, the sensor check is complete.

If the sensor checks have not completed, the ABS warning light will keep blinking while the vehicle is being driven, and the ABS will not operate.

(h) Reading Sensor Check DTCs

(1) Read the DTCs by following the Techstream screen.

NOTICE:

  • If only DTCs other than Test Mode sensor check DTCs are output, repair the malfunction and clear the DTCs.
  • If Test Mode sensor check DTCs and other DTCs are output or if only Test Mode sensor check DTCs are output, repair the malfunction, clear the DTCs, and perform the Test Mode inspection again.

HINT:

See Sensor Check DTCs.

(2) Turn the power switch off and disconnect the Techstream.

(i) Sensor Check DTCs

ABS Sensor

DTC No.

Detection Item

Trouble Area

C1271

Low Output Signal of Front Speed Sensor RH
  • Front speed sensor RH
  • Sensor installation
  • Front speed sensor rotor RH (Front axle hub sub-assembly RH)

C1272

Low Output Signal of Front Speed Sensor LH
  • Front speed sensor LH
  • Sensor installation
  • Front speed sensor rotor LH (Front axle hub sub-assembly LH)

C1273

Low Output Signal of Rear Speed Sensor RH
  • Rear speed sensor RH
  • Sensor installation
  • Rear speed sensor rotor RH (Rear axle hub and bearing assembly RH)

C1274

Low Output Signal of Rear Speed Sensor LH
  • Rear speed sensor LH
  • Sensor installation
  • Rear speed sensor rotor LH (Rear axle hub and bearing assembly LH)

C1275

Abnormal Change in Output Signal of Front Speed Sensor RH
  • Front speed sensor RH
  • Front speed sensor rotor RH (Front axle hub sub-assembly RH)

C1276

Abnormal Change in Output Signal of Front Speed Sensor LH
  • Front speed sensor LH
  • Front speed sensor rotor LH (Front axle hub sub-assembly LH)

C1277

Abnormal Change in Output Signal of Rear Speed Sensor RH
  • Rear speed sensor RH
  • Rear speed sensor rotor RH (Rear axle hub and bearing assembly RH)

C1278

Abnormal Change in Output Signal of Rear Speed Sensor LH
  • Rear speed sensor LH
  • Rear speed sensor rotor LH (Rear axle hub and bearing assembly LH)

C1279

Acceleration Sensor Output Voltage Malfunction
  • Sensor installation
  • Acceleration sensor (Airbag ECU assembly)

C1281

Master Cylinder Pressure Sensor Output Malfunction
  • Stop light switch assembly
  • Regulator pressure sensor (Brake booster with master cylinder assembly)
Electronically Controlled Brake System Sensor

DTC No.

Detection Item

Trouble Area

C1346

Stroke Sensor Zero Point Learning Malfunction
  • Brake pedal stroke sensor assembly
  • Brake pedal stroke sensor assembly circuit

HINT:

The codes in this table are output only in Test Mode (signal check).

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