Inspection Procedure

HINT:

If any DTCs other than the misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition 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 ignition plugs have been contaminated.
4. The problem is complex.
After finishing repairs, check the misfire counts of the cylinders (CYL #1, #2, #3 and #4).
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 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 or scan tool.
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 a hand-held tester or OBD II scan tool to the DLC3.
Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Read DTCs.

Result:

DTC RESULT

Display (DTC Output)	Proceed To
P0300, P0301, P0302, P0303 and/or P0304	A
P0300, P0301, P0302, P0303 and/or P0304 and other DTCs	B

HINT:

If any other DTCs besides P0300, P0301, P0302, P0303 and P0304 are output, perform troubleshooting for those DTCs first.

B : Go to DIAGNOSTIC TROUBLE CODE TABLE
A : GO TO NEXT STEP

READ VALUE USING HAND-HELD TESTER (MISFIRE RPM AND MISFIRE LOAD)
NOTE: If a hand-held tester is not available, proceed to step 3.
1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch to 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 the MISFIRE LOAD (engine load) values.
HINT:

The MISFIRE RPM and MISFIRE LOAD indicate the vehicle conditions under which the misfire occurred.
1. NEXT
CHECK PCV HOSE CONNECTIONS
OK : PCV hose is connected correctly, and is not damaged.
1. NG : REPAIR OR REPLACE PCV HOSE
2. OK : GO TO NEXT STEP

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

Connect the hand-held tester or OBD II scan tool to the DLC3.
Turn the ignition switch to ON.
Turn the tester or scan tool ON.
Clear DTC (see DTC CHECK/CLEAR ).
If using an OBD II scan tool, go to step 5.
On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / CYL #1, #2, #3 and #4.
Allow the engine to idle.
Read each value of CYL #1 to #4 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 ( d) and ( f) above.
3. Check the CYL #1 to #4.
4. If misfire counts are still not displayed, repeat ( g) 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 #4 or DTCs displayed on the tester.

Result:

RESULT

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 cylinder head cover No. 2.
Remove the ignition coil and the spark plug of misfire cylinder.
Measure the spark plug electrode gap.
Standard:

Between 0.7 mm and 0.8 mm (0.028 in. and 0.032 in.)

Maximum electrode gap: 1.16 mm (0.046 in.)

Check the electrode for carbon deposits.

Fig 1: Measuring Spark Plug Electrode Gap

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Recommended spark plug:

RECOMMENDED SPARK PLUG SPECIFICATIONS

DENSO	K16R-U
NGK	BKR5EYA

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 to prevent the engine starting.
2. Install the spark plug to the ignition coil.
3. Attach the spark plug to the cylinder head cover.
4. Crank the engine within 2 seconds and check the spark.
  OK : Spark jumps across electrode gap
5. Reconnect the injector connectors.
  
  Fig 2: Checking Sparks & Ignition
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Go to step 8
2. OK : GO TO NEXT STEP
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER (See INSPECTION )
1. Measure the cylinder compression pressure of the misfiring cylinder.
1. OK : Go to step 9
2. NG : REPAIR OR REPLACE MALFUNCTION PARTS
CHANGE NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
1. Change to a normal 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 sparks occur while the engine is being cranked.
  OK: Spark jumps across electrode gap.
1. NG : REPLACE IGNITION COIL NO.1 (See COMPONENTS ) THEN CONFIRM THAT THERE IS NO MISFIRE
2. OK : REPLACE SPARK PLUG

INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#1, #2, #3 AND/OR #4 VOLTAGE)

Turn the ignition switch to ON.

Measure the voltage between the terminals of the E3 ECM connector.

Standard:

E3 ECM CONNECTOR VOLTAGE SPECIFICATIONS

Tester Connections	Specified Conditions
#1 (E3-1) - E01 (E3-7)	Between 9 V and 14 V
#2 (E3-2) - E01 (E3-7)	Between 9 V and 14 V
#3 (E3-3) - E01 (E3-7)	Between 9 V and 14 V
#4 (E3-4) - E01 (E3-7)	Between 9 V and 14 V

Fig 3: Inspecting ECM Terminal Of Misfiring Cylinder (#1, #2, #3 And/Or #4 Voltage)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : Go to step 11
NG : GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR (INJECTOR - ECM)

Disconnect the injector connector (of the misfire cylinder).
Disconnect the E3 ECM connector.
Turn the ignition switch to ON.

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

Standard (Cylinder No. 1):

INJECTOR CONNECTOR RESISTANCE SPECIFICATIONS (CYLINDER NO. 1)

Tester Connections	Specified Conditions
I6-1 - Ground	Between 11 V and 14 V
I6-2 - Ground	10 kΩ or higher
I6-2 - #1 (E3-1)	Below 1 Ω

Standard (Cylinder No. 2):

INJECTOR CONNECTOR RESISTANCE SPECIFICATIONS (CYLINDER NO.2)

Tester Connections	Specified Conditions
I7-1 - Ground	Between 11 V and 14 V
I7-2 - Ground	10 kΩ or higher
I7-2 - #2 (E3-2)	Below 1 Ω

Standard (Cylinder No. 2):

Fig 4: Disconnecting Injector Connector

INJECTOR CONNECTOR RESISTANCE SPECIFICATIONS (CYLINDER NO.2)

Tester Connections	Specified Conditions
I8-1 - Ground	Between 11 V and 14 V
I8-2 - Ground	10 kΩ or higher
I8-2 - #3 (E3-3)	Below 1 Ω

Fig 5: Disconnecting E3 ECM Connector

Standard (Cylinder No. 2):

INJECTOR CONNECTOR RESISTANCE SPECIFICATIONS (CYLINDER NO.2)

Tester Connections	Specified Conditions
I9-1 - Ground	Between 11 V and 14 V
I-2 - Ground	10 kΩ or higher
I9-2 - #4 (E3-4)	Below 1 Ω

Reconnect the injector connector.
Reconnect the ECM connector.

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
OK : GO TO NEXT STEP

CHECK FUEL INJECTOR OF MISFIRING CYLINDER (See INSPECTION )
1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor).
1. NG : REPLACE FUEL INJECTOR ASSY
2. OK : GO TO NEXT STEP
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER (See ADJUSTMENT )
1. NG : ADJUST VALVE CLEARANCE (See ADJUSTMENT )
2. OK : GO TO NEXT STEP
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leaks.
  OK : No leakage from air induction system.
1. NG : REPAIR OR REPLACE AIR INDUCTION SYSTEM
2. OK : GO TO NEXT STEP
CHECK VALVE TIMING
1. Remove the cylinder head cover (see REPLACEMENT ).
2. Turn the crankshaft pulley, then align its groove with the timing mark "0" of the timing chain cover.
3. Check that both timing marks on the camshaft timing sprocket and camshaft timing gear are facing upward as shown in the illustration.
  If not, turn the crankshaft 1 revolution (360°), then align the marks as above.
  
  OK: Point marks on camshaft timing gears are aligned with timing chain cover surface.
4. Reinstall the cylinder head cover (see REPLACEMENT ).
  
  Fig 6: Identifying Timing Mark
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : ADJUST VALVE TIMING (See REPLACEMENT )
2. OK : GO TO NEXT STEP
CHECK FUEL PRESSURE (See ON-VEHICLE INSPECTION )
1. Check the fuel pressure.
1. NG : CHECK AND REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER
2. OK : GO TO NEXT STEP
READ VALUE USING HAND-HELD TESTER OR OBD II SCAN TOOL (COOLANT TEMP)
1. Connect the hand-held tester or OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the tester or scan tool ON.
4. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.
5. Read the COOLANT TEMP twice, when the engine is both cold and warmed up.
6. If using an OBD II scan tool, refer to the instruction manual.
  Standard:
  
  With cold engine: Same as ambient air temperature.
  
  With warm engine: Between 75°C and 95°C (167°F and 203°F).
1. NG : REPLACE ENGINE COOLANT TEMPERATURE SENSOR
2. OK : GO TO NEXT STEP
READ VALUE USING HAND-HELD TESTER OR OBD II SCAN TOOL (MAF)
1. Connect the hand-held tester or OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the tester or scan tool ON.
4. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF and COOLANT TEMP.
5. Allow the engine to idle until the 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.
7. If using an OBD II scan tool, refer to the instruction manual.
  Standard:
  
  MAF while engine idling: Between 1.4 gm/s and 2.3 gm/s (shift position: N, A/C: OFF).
  
  MAF at engine speed of 2,500 rpm: Between 5.4 gm/s and 7.9 gm/s (shift position: N, A/C: OFF).
1. NG : REPLACE MASS AIR FLOW METER
2. OK : (See CHECK FOR INTERMITTENT PROBLEMS )