M20A-FKS (ENGINE MECHANICAL): ENGINE: ON-VEHICLE INSPECTION; 2023 - 2025 MY Corolla Corolla Hatchback [11/2022

Last Modified: 05-13-2024	6.11:8.1.0	Doc ID: RM1000000028COO
Model Year Start: 2023	Model: Corolla Hatchback	Prod Date Range: [11/2022 - ]
Title: M20A-FKS (ENGINE MECHANICAL): ENGINE: ON-VEHICLE INSPECTION; 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 - ]

ON-VEHICLE INSPECTION

CAUTION / NOTICE / HINT

CAUTION:

To prevent injury due to contact with an operating V-ribbed belt or cooling fan, keep your hands and clothing away from the V-ribbed belt and cooling fans when working in the engine compartment with the engine running or the engine switch on (IG).

PROCEDURE

1. INSPECT ENGINE COOLANT

Click here

2. INSPECT ENGINE OIL

Click here

3. INSPECT BATTERY CONDITION

Click here

4. INSPECT SPARK PLUG

Click here

5. INSPECT AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

Click here

6. INSPECT V-RIBBED BELT

Click here

7. INSPECT V-RIBBED BELT TENSIONER ASSEMBLY

(a) Remove the V-ribbed belt.

Click here

(b) Turn the V-ribbed belt tensioner assembly clockwise and counterclockwise and check that it turns smoothly and does not catch.

HINT:

If the V-ribbed belt tensioner assembly does not turn smoothly or catches, replace the V-ribbed belt tensioner assembly.

Click here

8. INSPECT VALVE LASH ADJUSTER ASSEMBLY NOISE

(a) Rev up the engine several times. Check that the engine does not emit unusual noises.

(b) If tappet noise is heard, perform the following procedure.

(1) Idle the engine for at least 10 minutes and then stop the engine.

(2) Remove the fuel pump assembly (for High Pressure).

Click here

(3) Remove the ignition coil assembly.

Click here

(4) Remove the camshaft position sensor (for Intake Side).

Click here

(5) Remove the camshaft position sensor (for Exhaust Side).

Click here

(6) Disconnect the air fuel ratio sensor connector.

(7) Disengage the 3 clamps.

(8) Remove the cylinder head cover sub-assembly.

Click here

(9) Push the pivot of the No. 1 valve rocker arm sub-assembly.

*1	No. 1 Valve Rocker Arm Sub-assembly
*2	Valve Lash Adjuster Assembly
*3	Valve Stem Cap
*a	Pivot
	Push

OK:

The plunger is very difficult to move.

HINT:

If the plunger is easy to move, replace the valve lash adjuster assembly.

(10) Install the cylinder head cover sub-assembly.

Click here

(11) Engage the 3 clamps.

(12) Connect the air fuel ratio sensor connector.

(13) Connect the camshaft position sensor (for Exhaust Side) connector.

(14) Connect the camshaft position sensor (for Intake Side) connector.

(15) Install the ignition coil assembly.

Click here

(16) Install the fuel pump assembly (for High Pressure).

Click here

9. INSPECT IGNITION TIMING

NOTICE:

Check the ignition timing with the cooling fan off.
Turn off all electrical systems and the A/C.
When checking the ignition timing, the transaxle should be in neutral or park.

(a) Warm up and stop the engine.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Data List / Ignition Timing Cylinder #1.

Powertrain > Engine > Data List

Tester Display
Ignition Timing Cylinder #1

Standard Ignition Timing:

-3 to 3° BTDC at idle

(f) Enter the following menus: Powertrain / Engine / Active Test / Activate the TC Terminal / ON.

Powertrain > Engine > Active Test

Active Test Display
Activate the TC Terminal

Data List Display
Ignition Timing Cylinder #1

(g) Monitor Ignition Timing Cylinder #1 of the Data List.

Standard Ignition Timing:

8 to 12° BTDC at idle

(h) Enter the following menus: Powertrain / Engine / Active Test / Activate the TC Terminal / OFF.

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

10. INSPECT ENGINE IDLE SPEED

NOTICE:

Check the engine idle speed with the cooling fan off.
Turn off all electrical systems and the A/C.
When checking the engine idle speed, the transaxle should be in neutral or park.

(a) Warm up and stop the engine.

(b) Connect the Techstream to the DLC3.

(d) Turn the Techstream on.

(e) Enter the following menus: Powertrain / Engine / Data List / Engine Speed.

Powertrain > Engine > Data List

Tester Display
Engine Speed

(f) Read the value displayed on the tester.

Standard Idle Speed:

750 to 850 rpm

11. INSPECT COMPRESSION

NOTICE:

Keep the spark plug holes free of foreign matter when measuring the compression pressure.

(a) Warm up and stop the engine.

(b) Check for DTCs.

Click here

(d) Disconnect the fuel injector connector (for Port Injection).

(e) Remove the radiator support opening cover.

for Hatchback except GR
Click here
for Sedan with Illumination
Click here
for Sedan without Illumination
Click here

(f) Remove the inlet No. 1 air cleaner.

Click here

(g) Remove the 2 bolts and disengage the clamp to separate the engine wire.

(h) Remove the No. 1 engine under cover assembly.

Click here

(i) Disconnect the fuel injector connector (for Direct Injection).

(j) Remove the air cleaner cap with air cleaner hose.

Click here

(k) Using an 8 mm socket wrench, remove the 3 bolts to separate the throttle body with motor assembly from the intake manifold.

(l) Check the cylinder compression pressure.

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

(2) While cranking the engine, measure the compression pressure.

Standard Compression Pressure:

1400 kPa (14.3 kgf/cm², 203 psi)

Minimum Compression Pressure:

1200 kPa (12.2 kgf/cm², 174 psi)

Pressure Difference between Each Cylinder:

200 kPa (2.0 kgf/cm², 29 psi) or less

NOTICE:

Always use a fully charged battery to obtain an engine speed of 250 rpm or more.
Inspect all cylinders in the same way.
Measure the compression pressure as quickly as possible.

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

HINT:

If adding oil increases the compression pressure, the piston rings and/or cylinder bore may be worn or damaged.
If the compression pressure stays low, a valve may be stuck or seated improperly, or there may be leaks in the cylinder head gasket.

(m) Using an 8 mm socket wrench, install the throttle body with motor assembly to the intake manifold with the 3 bolts.

Torque:

10 N·m {102 kgf·cm, 7 ft·lbf}

(n) Install the air cleaner cap with air cleaner hose.

Click here

(o) Connect the fuel injector connector (for Direct Injection).

(p) Install the No. 1 engine under cover assembly.

Click here

(q) Engage the clamp and install the engine wire with the 2 bolts.

Torque:

10 N·m {102 kgf·cm, 7 ft·lbf}

(r) Install the inlet No. 1 air cleaner.

Click here

(s) Install the radiator support opening cover.

for Hatchback except GR
Click here
for Sedan with Illumination
Click here
for Sedan without Illumination
Click here

(t) Connect the fuel injector connector (for Port Injection).

(u) Install the 4 spark plugs.

Click here

(v) Clear the DTCs.

Click here

NOTICE:

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

12. INSPECT CO/HC

HINT:

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

(a) Start the engine.

(b) Run the engine at 2500 rpm for approximately 180 seconds.

(d) Immediately check the CO/HC concentration during idle and when the engine is running at 2500 rpm.

HINT:

When performing a 2 mode (with the engine idling/running at 2500 rpm) test, the measurement procedures are determined by applicable local regulations.

If the CO/HC concentration does not comply with the regulations, perform troubleshooting in the order given below.

(1) Check for DTCs.

Click here

(2) See the following table for possible causes, then inspect the applicable parts and repair them if necessary.

CO	HC	Problem	Cause
Normal	High	Rough idle	Faulty ignition: Incorrect valve timing Fouled, shorted or improperly gapped spark plugs Incorrect valve clearance (valve lash adjuster assembly) Leaks in intake or exhaust valves Leaks in cylinders Faulty EGR
Low	High	Rough idle (Fluctuating HC reading)	Vacuum leaks: PCV hoses Intake manifold Throttle body with motor assembly Lean mixture causing misfire Faulty EGR
High	High	Rough idle (Black smoke from exhaust)	Restricted air cleaner filter element sub-assembly Plugged PCV valve Faulty SFI systems: Fuel pressure regulator assembly Engine coolant temperature sensor Mass air flow meter ECM Fuel injector assemblies Throttle position sensor (built into throttle body with motor assembly) Faulty EGR