Inspection Procedure

HINT:

If any DTCs other than the misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using an intelligent tester. Freeze frame data record the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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 recur when the vehicle is brought to the workshop, reproduce the conditions stored in the freeze frame data.
The misfire still cannot be reproduced even though the conditions stored in the freeze frame data have been duplicated, one of the following factors is considered to be a possible cause of the problem:
1. The fuel tank is low full.
2. Improper fuel is used.
3. The spark plugs have been contaminated.
4. The problem is complex due to multiple factors.
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 repairs.
For 6 and 8 cylinder engines, the ECM intentionally does not set the specific misfiring cylinder DTCs at 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 DTCs (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 the COOLANT TEMP in the freeze frame data is less than 75°C (167°F), the misfires have occurred only while warming up the engine.

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

Connect an intelligent tester to the DLC3.
Turn the ignition switch ON.
Turn the tester ON.
Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Read DTCs.

Result

DTC RESULT DESCRIPTION

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 USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
1. Connect an intelligent tester to the DLC3.
2. Turn the ignition switch ON and turn the tester ON.
3. Select the following menu items: 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 indicate the vehicle conditions under which the misfire occurred.
CHECK PCV 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 an intelligent tester to the DLC3.
Turn the ignition switch ON.
Turn the tester ON.
Clear DTCs (See DTC CHECK/CLEAR ).
Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / MISFIRE / CYL #1, #2, #3, #4, #5 and #6.
Allow the engine to idle.
Read each value of CYL #1 to #6 displayed on the tester. If no misfire counts occur in any cylinders, perform the following operations:
1. Shift the gear selector lever to the D position.
2. Repeat steps ( e) to ( g) above.
3. Check the CYL #1 to #6.
4. If misfire counts are still not displayed, perform steps ( h) and ( i) and then check the misfire counts again.
Drive the vehicle with the MISFIRE RPM and MISFIRE LOAD noted in step 2.

Read the CYL #1 to #6 or DTCs displayed on the tester.

Result

DTC RESULT DESCRIPTION

Misfire Count	Proceed To
One or two cylinders have misfire counts	A
Three 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.
Standard:

1.0 to 1.1 mm (0.039 to 0.043 in.)

Check the electrode for carbon deposits.

Recommended spark plug

DIAGNOSTIC PROCEDURE

Manufactures	Products
DENSO	K20HR-U11
NGK	LFR6C11

Fig 1: Identifying Spark Plug Electrode Gap

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Reinstall the ignition coil and the spark plug.

NG: REPLACE SPARK PLUG

OK: Go TO NEXT STEP

CHECK 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 spark.
  OK:
  
  Sparks jump across electrode gap
5. Reconnect the injector connectors.
NG: Go to step 8

OK: Go TO NEXT STEP
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
1. Measure the cylinder compression pressure of the misfiring cylinder.
OK: Go to step 9

NG: REPAIR OR REPLACE MALFUNCTION PARTS
CHANGE NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
1. Change the installed spark plug to 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 electrode gap.
NG: REPLACE IGNITION COIL ASSEMBLY THEN CONFIRM THAT THERE IS NO MISFIRE

OK: REPLACE SPARK PLUG

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

Turn the ignition switch ON.

Measure the voltage between the terminals of the B1 and B3 ECM connectors.

Standard Voltage

STANDARD VOLTAGE SPECIFICATIONS

Tester Connections	Specified Conditions
#10 (B3-2) - E01 (B1-7)	11 to 14 V
#20 (B3-3) - E01 (B1-7)
#30 (B3-4) - E01 (B1-7)
#40 (B3-5) - E01 (B1-7)
#50 (B3-6) - E01 (B1-7)
#60 (B3-7) - E01 (B1-7)

OK: Go to step 11

Fig 2: Identifying B1 & B3 ECM Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: Go TO NEXT STEP

CHECK HARNESS AND CONNECTOR (INJECTOR - ECM)

Disconnect the injector connector (of the misfiring cylinder).
Disconnect the B3 ECM connector.
Turn the ignition switch ON.

Measure the resistance and voltage between the injector and the ECM connector terminals.

Standard (Cylinder No. 1)