Inspection Procedure

HINT:

If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction (See FREEZE FRAME DATA ).
If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.
If the misfire still cannot be reproduced even though the conditions stored in the ECM as freeze frame data have been reproduced, one of the following factors is considered to be a possible cause of the problem:
1. There was insufficient fuel in the tank.
2. Improper fuel is used.
3. The spark plugs have been contaminated.
4. The problem requires further diagnosis.
After finishing repairs, check the misfire counts of the cylinders (CYL #1, #2, #3, #4, #5 and #6).
Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern after finishing repairs.
For 6 and 8 cylinder engines, the ECM intentionally does not set the specific misfiring cylinder DTCs at a high engine RPM. If misfires occur only in high engine RPM areas, only DTC P0300 is set.
In the event of DTC P0300 being present, perform the following operations:
1. Clear the DTC (See DTC CHECK/CLEAR ).
2. Start the engine and conduct the confirmation driving pattern.
3. Read the misfiring rates of each cylinder or DTC (s) using the tester.
4. Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
5. After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not set.
When one of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data is outside the range of +-20%, the air-fuel ratio may be RICH (-20% or less) or LEAN (+20% or more).
When COOLANT TEMP in the freeze frame data is less than 75°C (167°F), misfires have occurred only while warming up the engine.

CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the tester on.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Read the DTCs.

Result

RESULT REFERENCE

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

HINT:

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

B: GO TO DIAGNOSTIC TROUBLE CODE TABLE

A: Go to Next Step

READ VALUE OF INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
1. Connect the intelligent tester to the DLC3.
2. Turn the engine switch on (IG) and turn the 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 MISFIRE LOAD (engine load) values.
  HINT:
  
  The MISFIRE RPM and MISFIRE LOAD values indicate the vehicle conditions under which the misfire occurred.
CHECK PCV HOSE (HOSE CONNECTIONS)
OK:

PCV hose is connected correctly and is not damaged.

NG: REPAIR OR REPLACE PCV HOSE

OK: Go to Next Step

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

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the tester on.
Clear the DTCs.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / MISFIRE / CYL #1, #2, #3, #4, #5 and #6 (Step "A").
Allow the engine to idle (Step "B").
Read the value of CYL #1 to #6 displayed on the tester. If no misfire counts occur in any cylinders, perform the following operations (Step "C"):
1. Shift the gear selector lever to the D position.
2. Repeat steps "A" to "C" above.
3. Check the CYL #1 to #6.
4. If misfire counts are still not displayed, perform steps "D" and "E" and then check the misfire counts again.
Drive the vehicle with MISFIRE RPM and MISFIRE LOAD noted in step 2 (Step "D").

Read CYL #1 to #6 or DTCs displayed on the tester (Step "E").

Result

RESULT REFERENCE

Misfire count	Proceed to
1 or 2 cylinders have misfire counts	A
3 cylinders or more have misfire counts	B

B: Go to step 13

A: Go to Next Step

CHECK SPARK PLUG

Remove the ignition coil and the spark plug of the misfiring cylinder.
Measure the spark plug electrode gap.

Fig 1: Measuring Spark Plug Electrode Gap
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

Between 1.0 mm and 1.4 mm (0.039 in. and 0.055 in.)

Check the electrode for carbon deposits.

Recommended spark plug:

SPARK PLUG SPECIFICATION

Manufacturer	Product
DENSO	FK20HR11

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

NG: REPLACE SPARK PLUG

OK: Go to Next Step

CHECK FOR SPARKS AND IGNITION
1. Disconnect the injector connectors, in order to prevent the engine from starting.
2. Install the spark plug to the ignition coil.
3. Attach the spark plug assembly to the cylinder head cover.
4. Crank the engine for less than 2 seconds and check the sparks.
  OK:
  
  Sparks jump across the electrode gap.
5. Reconnect the injector connectors.
NG: Go to step 8

OK: Go to next step
CHECK CYLINDER COMPRESSION PRESSURE (MALFUNCTION CYLINDER)
1. Measure the cylinder compression pressure of the misfiring cylinder.
OK: Go to step 9

NG: REPAIR OR REPLACE ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
CHANGE SPARK PLUG WITH NORMAL ONE AND CHECK FOR SPARKS OF MISFIRING CYLINDER
1. Change the installed spark plug with a spark plug that functions normally.
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 sparks occur while the engine is being cranked.
    OK:
    
    Sparks jump across the electrode gap.
NG: REPLACE IGNITION COIL ASSEMBLY (See REMOVAL )

OK: REPLACE SPARK PLUG

INSPECT ECM (#10, #20, #30, #40, #50 AND/OR #60 VOLTAGE))

Disconnect the B12 ECM connector.

Fig 2: Identifying B12 ECM Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Turn the engine switch on (IG).

Measure the voltage between the terminals.

Standard voltage

VOLTAGE SPECIFICATION

Tester Connection	Specified Condition
#10 (B12-45) - E01 (B12-22)	9 to 14 V
#20 (B12-85) - E01 (B12-22)	9 to 14 V
#30 (B12-44) - E01 (B12-22)	9 to 14 V
#40 (B12-84) - E01 (B12-22)	9 to 14 V
#50 (B12-43) - E01 (B12-22)	9 to 14 V
#60 (B12-83) - E01 (B12-22)	9 to 14V

Reconnect the ECM connector.

OK: Go to step 12

NG: Go to Next Step

CHECK HARNESS AND CONNECTOR (INJECTOR - ECM)

Disconnect the injector connector (misfire cylinder).
Disconnect the B12 ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard resistance

RESISTANCE REFERENCE TABLE

Tester Connection	Specified Condition
#10 (B12-45) - B16-1	Below 1 Ω
#20 (B12-85) - B17-1	Below 1 Ω
#30 (B12-44) - B18-1	Below 1 Ω
#40 (B12-84) - B19-1	Below 1 Ω
#50 (B12-43) - B20-1	Below 1 Ω
#60 (B12-83) - B21-1	Below 1 Ω
#10 (B12-45) or B16-1 - Body ground	10 kΩ or higher
#20 (B12-85) or B17-1 - Body ground	10 kΩ or higher
#30 (B12-44) or B18-1 - Body ground	10 kΩ or higher
#40 (B12-84) or B19-1 - Body ground	10 kΩ or higher
#50 (B12-43) or B20-1 - Body ground	10 kΩ or higher
#60 (B12-83) or B21-1 - Body ground	10 kΩ or higher

Fig 3: Identifying B12 ECM Connector Terminal

Reconnect the injector connector.
Reconnect the ECM connector.

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

CHECK FUEL INJECTOR ASSEMBLY (MISFIRING CYLINDER)
1. Check the injector injection (whether fuel volume high or low, and whether injection pattern is poor).
NG: REPLACE FUEL INJECTOR ASSEMBLY (See REMOVAL )

OK: Go to Next Step
CHECK VALVE CLEARANCE (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 cylinder head covers.
2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.
3. Check that the timing marks of the camshaft timing gears are aligned with the timing marks of the bearing cap.
  If not, turn the crankshaft 1 revolution (360°) and align the marks as above.
  
  OK:
  
  The timing marks on the camshaft timing gears are aligned.
  
  Fig 4: Identifying Matchmarks Of Crankshaft & Camshaft Pulley
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reinstall the cylinder head covers.
NG: ADJUST VALVE TIMING

OK: Go to Next Step

CHECK FUEL PRESSURE

Check the fuel pressure (high or low pressure).

Standard

FUEL PRESSURE SPECIFICATION

Item	Standard Condition
Fuel pressure	147 kPa (1.5 kgf/cm² , 21 psi)

NG: CHECK AND REPLACE FUEL SYSTEM

OK: Go to Next Step

READ VALUE ON INTELLIGENT TESTER (COOLANT TEMP)
1. Connect the intelligent tester to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the tester on.
4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
5. Read COOLANT TEMP twice, when the engine is both cold and warmed up.
  Standard:
  
  With cold engine:
  
  Same as ambient air temperature.
  
  With warm engine:
  
  Between 75°C and 95°C (167°F and 203°F).
NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See REMOVAL )

OK: Go to Next Step
READ VALUE OF INTELLIGENT TESTER (MAF)
1. Connect the intelligent tester to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the tester on.
4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / MAF and COOLANT TEMP.
5. Allow the engine to idle until COOLANT TEMP reaches 75°C (167°F) or more.
6. Read the MAF with the engine in an idling condition and at an engine speed of 2,500 rpm.
  Standard:
  
  MAF while engine is idling:
  
  Between 2.1 g/sec and 3.1 g/sec (shift position: N, A/C: OFF).
  
  MAF at an engine speed of 2,500 rpm:
  
  Between 7.8 g/sec and 11.4 g/sec (shift position: N, A/C: OFF).
NG: REPLACE MASS AIR FLOW METER (See REMOVAL )

OK: Go to Next Step
CHECK MISFIRE COUNT (CYL #1, #2, #3, #4, #5 AND #6)
HINT:
- If the result of step 4 is "1 or 2 cylinders", proceed to A.
- If the result of step 4 is "more than 3 cylinders", proceed to B.
B: Go to step 5

A: CHECK FOR INTERMITTENT PROBLEMS