Inspection Procedure

HINT:

If DTCs other than misfire DTCs are output simultaneously, troubleshoot the non-misfire DTCs first.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
If the misfire does not occur when the vehicle is brought to the workshop, the misfire can be confirmed by reproducing the conditions recorded in the freeze frame data. Also, after finishing repairs, confirm that no misfire occurs (see confirmation driving pattern).
On 6 and 8 cylinder engines, cylinder-specific misfire fault codes are disabled at high engine speeds. If the misfire starts in a high engine speed range or the misfire occurs only in a high engine speed area, only general fault code P0300 will be stored.
When only P0300 is stored:
1. Erase the general misfire fault code from the intelligent tester.
2. Start the engine and drive the confirmation pattern (see CONFIRMATION DRIVING PATTERN ).
3. Read the value of the misfire ratio for each cylinder. Or, check if a DTC was output.
4. Perform repairs on the cylinder that has a high misfire ratio. Or repair the cylinder indicated by any output DTCs.
5. After finishing repairs, drive the confirmation pattern again and confirm that no misfire occurs.
If either SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data is +-20%, there is a possibility that the air fuel ratio is becoming RICH (-20% or less) or LEAN (+20% or more).
When COOLANT TEMP in the freeze frame data is less than 75°C (167°F), a misfire is only possible during engine warm-up.
If the misfire cannot be reproduced, the cause may be: 1) low fuel in the vehicle, 2) improper fuel in the vehicle, 3) a contaminated ignition plug, or 4) another problem.
Be sure to check the value on the misfire counter after repairs.

CHECK OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS)

Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
Turn the ignition switch ON and turn the intelligent tester ON.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
Read the CURRENT CODES.

Result

RESULT CHART

Display (DTC output)	Proceed to
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308	A
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308 and other DTCs	B

HINT:

If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.

B: GO TO DIAGNOSTIC TROUBLE CODE CHART

A: GO TO Next Step

READ VALUE OF INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
2. Turn the ignition switch ON and turn the intelligent tester ON.
3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / MISFIRE / MISFIRE RPM and MISFIRE LOAD.
4. Read and note the MISFIRE RPM and the MISFIRE LOAD (engine load) with the DATA LIST.
HINT:

The MISFIRE RPM and MISFIRE LOAD displays have vehicle data that can help lead to successful repairs of any misfiring cylinders.
CHECK CONNECTION OF VENTILATION HOSE
OK: Ventilation hose is connected correctly and is not damaged.

NG: REPAIR OR REPLACE VENTILATION HOSE

OK: GO TO Next Step

CHECK MISFIRE COUNT (CYL #1, #2, #3, #4, #5, #6, #7, #8)

Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
Turn the ignition switch ON and turn the intelligent tester ON.
Clear the DTCs.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / MISFIRE.
Allow the engine to idle.
Read the misfire count of the cylinders #1 to #8.
If no misfire is counted for all of the cylinders, move the shift lever into the D position and repeat the 2 previous steps.

If misfires are still not counted, perform the next 2 steps.
Drive the vehicle with MISFIRE RPM and MISFIRE LOAD selected in the DATA LIST.
Read the misfire count of cylinders #1 to #8, or check for any output DTCs.

Result

RESULT CHART

Misfire count in each cylinder	Proceed to
1 or 2 cylinders have some misfire counts	A
3 cylinders or more have some misfire counts	B

HINT:

If it is difficult to reproduce misfires for each cylinder, check the DATA LIST item called MISFIRE MARGIN. Try to find vehicle driving conditions that lower the MISFIRE MARGIN value. Values above 30% are considered normal.
If the freeze frame data's record of the ECT is below 75°C (167°F), the misfire may be detected only when the engine is cold.
If the freeze frame data's record of the ENGINE RUN TIME is below 120 seconds, the misfire may be detected right after the engine is started.

B: GO TO step 14

A: GO TO Next Step

PERFORM ACTIVE TEST BY INTELLIGENT TESTER (FUEL CUT #1 TO #8)

Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
Turn the ignition switch ON and turn the intelligent tester ON.
Allow the engine to idle.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / FUEL CUT #1 (to #8).
If a cylinder has a high misfire count, cut fuel to the cylinder. Compare the misfire count of the cylinder before fuel cut and after fuel cut.

Result

RESULT CHART

Misfire count in each cylinder	Proceed to
Misfire count of the cylinder before fuel cut and after fuel cut are roughly the same	A
Misfire count of the cylinder before fuel cut is lower than after fuel cut	B

HINT:

If the misfire count of the cylinder before fuel cut and after fuel cut are roughly the same, the cylinder is misfiring.

If the misfire count of the cylinder before fuel cut is lower than after fuel cut, the cylinder misfires sometimes.

NOTE: This ACTIVE TEST cannot be performed while the vehicle is being driven.

B: GO TO step 12

A: GO TO Next Step

INSPECT SPARK PLUG

Remove the engine cover (see REMOVAL ).
Remove the ignition coil and the spark plug of misfire cylinder.
Measure the spark plug electrode gap.
Standard: The electrode gap is 1.0 to 1.3 mm (0.039 to 0.051 in.)
Check the electrode for carbon deposits.
Recommended spark plug

RECOMMENDED SPARK PLUG

Manufacturer	Spark Plug Type
DENSO	SK20R11
NGK	IFR6A11

Fig 1: Identifying Spark Plug Electrode Gap

NOTE: If the electrode gap is larger than the standard, replace the spark plug. Do not adjust the electrode gap.

NG: REPLACE SPARK PLUG

OK: GO TO Next Step

CHECK SPARK AND IGNITION
1. Disconnect the fuel injector connectors to prevent the engine from starting.
2. Install the spark plug to the ignition coil.
3. Attach the spark plug to the cylinder head cover.
4. Crank the engine for 2 seconds or less and check if a spark occurs.
  OK: Spark occurs
NG: GO TO step 9

Fig 2: Checking Spark And Ignition
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: GO TO Next Step
CHECK CYLINDER COMPRESSION PRESSURE ON MISFIRING CYLINDER
1. Measure the cylinder compression pressure of the misfiring cylinder.
OK: GO TO step 10

NG: CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
CHANGE NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
1. For inspection purposes, remove the current spark plug and install a normally functioning spark plug.
2. Perform a spark test.
CAUTION: Always disconnect each injector connector.

NOTE: Do not crank the engine for more than 2 seconds.
1. Install the spark plug to the ignition coil and connect the ignition coil connector.
2. Disconnect the injector connector.
3. Ground the spark plug.
4. Check if a spark occurs while the engine is being cranked.
  OK: Spark jumps across electrode gap.
OK: REPLACE SPARK PLUG

NG: REPLACE IGNITION COIL (THEN CONFIRM THAT THERE IS NO MISFIRE)

CHECK ECM (#10, #20, #30, #40, #50, #60, #70, #80 VOLTAGE)

Turn the ignition switch ON.
Measure the voltage of the ECM connectors.
Standard voltage

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Specified Condition
E7-2 (#10) - E5-7 (E01)	9 to 14 V
E7-3 (#20) - E5-7 (E01)	9 to 14 V
E7-4 (#30) - E5-7 (E01)	9 to 14 V
E7-5 (#40) - E5-7 (E01)	9 to 14 V
E7-6 (#50) - E5-7 (E01)	9 to 14 V
E7-7 (#60) - E5-7 (E01)	9 to 14 V
E5-3 (#70) - E5-7 (E01)	9 to 14 V
E5-2 (#80) - E5-7 (E01)	9 to 14 V

OK: CHECK FUEL INJECTOR OF MISFIRING CYLINDER

Fig 3: Identifying ECM Connector Terminals

NG: GO TO Next Step

CHECK HARNESS AND CONNECTOR (FUEL INJECTOR - ECM)
1. Check harness and connector (see ELECTRONIC CIRCUIT INSPECTION PROCEDURE ).
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO Next Step
CHECK FUEL INJECTOR OF MISFIRING CYLINDER
Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor).

NG: REPLACE FUEL INJECTOR

OK: GO TO Next Step
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
NG: ADJUST VALVE CLEARANCE

OK: GO TO Next Step
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leakage.
OK: No leakage from air induction system

NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK: GO TO Next Step
CHECK VALVE TIMING
1. Remove the engine cover (see REMOVAL ).
2. Remove the drive belt (see REMOVAL ).
3. Remove the timing belt cover LH and RH (see REMOVAL ).
4. Turn the crankshaft to align the matchmarks of the crankshaft.
5. Align the notch of the crankshaft pulley with the "0" position.
6. Confirm whether the matchmarks of the camshaft pulley and cylinder head cover are facing each other.
7. If the matchmarks are not facing each other, turn the crankshaft clockwise by 360°. Confirm again if the matchmarks are facing each other.
  OK: The matchmarks of the camshaft pulley and the cylinder head cover face each other when the notch of the crankshaft pulley is in the "0" position.
NG: ADJUST VALVE TIMING

Fig 4: Identifying Matchmarks On Camshaft Pulley
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: GO TO Next Step
CHECK FUEL PRESSURE
Check the fuel pressure (see ON-VEHICLE INSPECTION ).

NG: CHECK AND REPLACE FUEL PUMP, FUEL PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER

OK: GO TO Next Step
READ VALUE OF INTELLIGENT TESTER (COOLANT TEMP)
1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
2. Turn the ignition switch ON and turn the intelligent tester ON.
3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
4. Read the COOLANT TEMP value when the engine is cold and warmed-up.
Standard:

ECT when the engine is cold: Same as ambient temperature

ECT when the engine is warmed-up: 75 to 95°C (167 to 203°F)

NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR

OK: GO TO Next Step
READ VALUE OF INTELLIGENT TESTER (MAF)
1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
2. Turn the ignition switch ON and turn the intelligent tester ON.
3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / MAF and COOLANT TEMP.
4. Allow the engine to idle until the COOLANT TEMP reaches 75°C (167°F) or more.
5. Read the MAF with the engine in an idling condition and at an engine speed of 2,500 rpm.
  Standard:
MAF at idle rpm: 4.0 to 8.0 g/sec. (shift lever is in N position and A/C is OFF)

MAF at 2,500 rpm: 10.0 to 20.0 g/sec. (shift lever is in N position and A/C is OFF)

NG: REPLACE MASS AIR FLOW METER

OK: CHECK FOR INTERMITTENT PROBLEMS