Lexus NX: On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. INSPECT ENGINE COOLANT

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2. INSPECT ENGINE OIL

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3. INSPECT AUXILIARY BATTERY

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4. INSPECT AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

(a) Remove the air cleaner cap sub-assembly.

(b) Remove the air cleaner filter element sub-assembly.

(c) Visually check that the air cleaner filter is not excessively damaged or oily.

If necessary, replace the air cleaner filter element sub-assembly.

(d) Install the air cleaner filter element sub-assembly.

(e) Install the air cleaner cap sub-assembly.

5. INSPECT SPARK PLUG

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6. INSPECT FAN AND GENERATOR V BELT

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7. INSPECT VALVE LASH ADJUSTER ASSEMBLY NOISE

(a) Put the engine in inspection mode (maintenance mode).

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(b) Warm up the engine.

(c) Check that the engine does not emit unusual noises.

(d) If unusual noises occur, warm up the engine and idle it for over 30 minutes. Then perform the inspection above again.

HINT:

If any defects or problems are found during the inspection above, check the valve lash adjuster assembly.

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8. INSPECT IGNITION TIMING

(a) Put the engine in inspection mode (maintenance mode).

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(b) Warm up and stop the engine.

(c) Connect the Techstream to the DLC3.

(d) Put the engine in inspection mode (maintenance mode).

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(e) Turn the Techstream on.

(f) Enter the following menus: Powertrain / Engine and ECT / Data List / IGN Advance.

Powertrain > Engine and ECT > Data List

Tester Display

IGN Advance

Standard ignition timing:

5 to 20° BTDC @ idle

NOTICE:

  • Turn all the electrical systems and the A/C off.
  • Check the ignition timing with the cooling fans off.
  • When checking the ignition timing, the shift lever should be in P.

(g) Check that the ignition timing advances immediately when the engine speed is increased.

(h) Enter the following menus: Powertrain / Engine and ECT / Active Test / Connect the TC and TE1.

Powertrain > Engine and ECT > Active Test

Tester Display

Connect the TC and TE1

(i) Monitor IGN Advance of the Data List.

Standard ignition timing:

8 to 12 BTDC @ idle

NOTICE:

  • Turn all the electrical systems and the A/C off.
  • Check the ignition timing with the cooling fans off.
  • When checking the ignition timing, the shift lever should be in P.

(j) Check that the ignition timing advances immediately when the engine speed is increased.

(k) Turn the power switch off.

(l) Disconnect the Techstream from the DLC3.

9. INSPECT ENGINE IDLE SPEED

(a) Put the engine in inspection mode (maintenance mode).

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(b) Warm up and stop the engine.

(c) When using the Techstream:

(1) Connect the Techstream to the DLC3.

(2) Put the engine in inspection mode (maintenance mode).

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(3) Start the engine and run it at idle.

(4) Turn the Techstream on.

(5) Enter the following menus: Powertrain / Engine and ECT / Data List / Engine Speed.

Powertrain > Engine and ECT > Data List

Tester Display

Engine Speed

Standard idle speed:

950 to 1050 rpm

NOTICE:

  • Turn all electrical systems and the A/C off.
  • Inspect the idle speed with the cooling fans off.
  • When checking the idle speed, the shift lever should be in P.

(6) Disconnect the Techstream from the DLC3.

(d) When not using the Techstream:

(1) Using SST, connect a tachometer probe to terminal 9 (TAC) of the DLC3.

SST: 09843-18030

NOTICE:

Confirm the terminal number before connecting the probe. Connecting the wrong terminals can damage the engine.

*a

Front view of DLC3

(2) Put the engine in inspection mode (maintenance mode).

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(3) Start the engine and run it at idle.

(4) Check the idle speed.

Standard idle speed:

950 to 1050 rpm

NOTICE:

  • Turn all electrical systems and the A/C off.
  • Inspect the idle speed with the cooling fans off.
  • When checking the idle speed, the shift lever should be in P.

(5) Disconnect the tachometer probe from the DLC3.

10. INSPECT COMPRESSION

(a) Put the engine in inspection mode (maintenance mode).

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(b) Warm up and stop the engine.

(c) Check for DTCs.

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(d) Remove the 4 spark plugs.

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NOTICE:

DTCs will be stored if the inspection is performed with the ignition coil assembly connectors disconnected. Make sure that the ignition coil assembly connectors are connected during the inspection.

(e) Check the cylinder compression pressure.

(1) Insert a compression gauge into the spark plug hole.

(2) Connect the Techstream to the DLC3.

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

(4) Turn the Techstream on.

NOTICE:

Check the HV battery voltage in the Data List to ensure that the battery is fully charged.

(5) Enter the following menus: Powertrain / Hybrid Control / Active Test / Compression Test / ON.

Powertrain > Hybrid Control > Active Test

Tester Display

Compression Test

(6) Depress and hold the brake pedal, and turn the power switch on (READY).

Standard compression pressure:

1100 kPa (11.2 kgf/cm2, 160 psi) or higher

Minimum compression pressure:

800 kPa (8.2 kgf/cm2, 116 psi)

Pressure difference between each cylinder:

100 kPa (1.0 kgf/cm2, 15 psi) or less

NOTICE:

  • Inspect the other cylinders in the same way.
  • Measure the compression pressure as quickly as possible.
  • Noise may be emitted from the hybrid vehicle transaxle assembly. However, this is not a malfunction.

(7) If the cylinder compression pressure is low, pour a small amount of engine oil into the cylinder through the spark plug hole, then inspect the cylinder compression pressure again.

HINT:

  • If adding oil helps boost the compression, it is likely that the piston rings and/or cylinder bore is worn or damaged.
  • If the pressure stays low, a valve may be stuck or seated improperly, or there may be leakage from the gasket.

(f) Remove the compression gauge.

(g) Install the 4 spark plugs.

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(h) Clear the DTCs.

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NOTICE:

After the inspection, clear the DTCs, check for DTCs again and make sure the normal system code is output.

11. INSPECT CO/HC

HINT:

This check determines whether or not the idle CO/HC complies with regulations.

(a) Put the engine in inspection mode (maintenance mode).

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(b) Start the engine.

(c) Keep the engine speed at 2500 rpm for approximately 180 seconds.

(d) Insert a CO/HC meter testing probe at least 40 cm (1.31 ft.) into the tailpipe during idling.

(e) Immediately check the CO/HC concentration at idle and at 2500 rpm.

HINT:

  • When performing the 2-mode (2500 rpm and idle) test, follow the measurement order prescribed by the applicable local regulations.
  • If the CO/HC concentration does not comply with regulations, troubleshoot in the order given below.

(1) Check the air fuel ratio sensor operation.

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(2) Check the heated oxygen sensor operation.

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(3) See the table below for possible causes, and then inspect and correct the applicable causes if necessary.

CO

HC

Symptom

Causes

Normal

High

Rough idle

  • 1. Faulty ignition
    • Incorrect timing
    • Fouled, shorted or improperly gapped plugs
  • 2. Incorrect valve clearance
  • 3. Leaky intake and exhaust valves
  • 4. Leaky cylinder
  • 5. Faulty EGR

Low

High

Rough idle

(Fluctuating HC reading)

  • 1. Vacuum leaks
    • PCV hose
    • Intake manifold
    • Throttle body
  • 2. Lean mixture causing misfire
  • 3. Faulty EGR

High

High

Rough idle

(Black smoke from exhaust)

  • 1. Restricted air filter
  • 2. Plugged PCV valve
  • 3. Faulty SFI system
    • Faulty pressure
    • Defective engine coolant temperature sensor
    • Faulty ECM
    • Faulty injector
    • Faulty throttle position sensor
    • Faulty mass air flow meter sensor
  • 4. Faulty EGR

READ NEXT:

 Engine Assembly

 Components

COMPONENTS ILLUSTRATION *1 DECK FLOOR BOX LH *2 NO. 3 DECK BOARD SUB-ASSEMBLY *3 REAR DECK FLOOR BOX *4 NEGATIVE AUXILIARY BATTERY TERMINAL N*m (kgf*cm, ft.*lbf): Specified

 Removal

REMOVAL CAUTION / NOTICE / HINT CAUTION: As the engine assembly with transaxle is extremely heavy, the engine lifter may suddenly drop if the instructions listed in the repair manual are not followed.

SEE MORE:

 Idle Control System (P0505)

DESCRIPTION The idle speed is controlled by the electronic throttle control system. The electronic throttle control system is comprised of: 1) one valve type throttle body with motor assembly; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects

 Dtc Check / Clear

DTC CHECK / CLEAR NOTICE: When using the Techstream with the power switch off, connect the Techstream to the DLC3 and turn a courtesy light switch on and off at intervals of 1.5 seconds or less until communication between the Techstream and the vehicle begins. Then select the vehicle type under manu

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