Inspection Procedure

WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using a Techstream. Freeze frame data records 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 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, the following factors are possible causes of the problem:
1. There is insufficient fuel in the tank.
2. Improper fuel is used.
3. The spark plugs are contaminated.
4. The problem requires further diagnosis.
After finishing repairs, check the misfire counts of the cylinders Cylinder #1 Misfire Rate to Cylinder #4 Misfire Rate.
Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern after finishing repairs.
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.
An extremely imbalanced drive wheel may cause misfire DTC detection, which can cause body vibration.

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

Connect a Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the tester ON.
Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.

Read DTCs.

Result

RESULT CHART

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

B: GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A: Go to next step

READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON and turn the tester ON.
3. Select the following menu items: Powertrain / Engine and ECT / Data List / Misfire / Misfire RPM and Misfire Load.
4. Read and note the Misfire RPM and Misfire Load values.
  HINT:
  
  The Misfire RPM and Misfire Load values 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

READ VALUE USING TECHSTREAM (CYLINDER #1 MISFIRE RATE, #2, #3 AND #4)

Select the following menu items: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Rate, #2, #3 and #4.
Start the engine and allow the engine to idle.
Read each value for Cylinder #1 Misfire Rate to #4 displayed on the tester. If no misfire counts occur in any cylinders, perform steps (d) and ( e) and then check the misfire counts again.
Drive the vehicle with the Misfire RPM and Misfire Load noted in the READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD) procedures above.

Read the Cylinder #1 Misfire Rate to #4 or DTCs displayed on the tester.

Result

RESULT CHART

Result (Misfire Count)	Proceed To
Most misfires occur in only 1 or 2 cylinders	A
3 cylinders or more have equal 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 immediately after the engine is started.

B: Go to step 16

A: Go to next step

INSPECT 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.)

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

Check the electrode for carbon deposits.

Recommended spark plug:

SPARK PLUG SPECIFICATION

Manufactures	Products
DENSO	SK16R11
NGK	IFR5A11

NOTE: If the electrode gap is out of 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 onto the ignition coil.
3. Attach the spark plug assembly to the cylinder head.
4. Crank the engine for less than 2 seconds and check the spark.
  OK:
  
  Sparks jump across electrode gap.
  
  Fig 2: Identifying Spark Plug For Sparks And Ignition
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Reconnect the injector connectors.
NG: Go to step 27

OK: Go to next step
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
1. Measure the cylinder compression pressure of the misfiring cylinder (See ON-VEHICLE INSPECTION ).
NG: CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK: Go to next step

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

Disconnect the C20 ECM connector.

Fig 3: Identifying C20 ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Turn the ignition switch to ON.

Measure the voltage between the terminals of the ECM connector.

Standard voltage

TESTER CONNECTIONS SPECIFIED CONDITIONS CHART

Tester Connections	Specified Conditions
#10 (C20-108) - E01 (C20-45)	11 to 14 V
#20 (C20-107) - E01 (C20-45)
#30 (C20-106) - E01 (C20-45)
#40 (C20-105) - E01 (C20-45)

Reconnect the ECM connector.

NG: GO TO FUEL INJECTOR CIRCUIT

OK: Go to next step

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

OK: Go to next step
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
1. Check the valve clearance of the misfiring cylinder (See ADJUSTMENT ).
NG: ADJUST VALVE CLEARANCE (See ADJUSTMENT )

OK: Go to next step
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leak.
  OK:
  
  No leak from air induction system.
NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK: Go to next step
CHECK VALVE TIMING (See INSPECTION PROCEDURE )
NG: ADJUST VALVE TIMING (See REMOVAL )

OK: Go to next step
CHECK FUEL PRESSURE
1. Check the fuel pressure (See ON-VEHICLE INSPECTION ).
NG: REPAIR OR REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER

OK: Go to next step
READ VALUE USING TECHSTREAM (COOLANT TEMP) (See INSPECTION PROCEDURE )
NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See REMOVAL )

OK: Go to next step
READ VALUE USING TECHSTREAM (MAF) (See INSPECTION PROCEDURE   )
NG: REPLACE MASS AIR FLOW METER (See REMOVAL   )

OK: REPLACE ECM (See REMOVAL   )
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leak.
  OK:
  
  No leak from air induction system.
NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK: Go to next step
CHECK VALVE TIMING (See INSPECTION PROCEDURE )
NG: ADJUST VALVE TIMING (See REMOVAL )

OK: Go to next step
CHECK FUEL PRESSURE
1. Check the fuel pressure (See ON-VEHICLE INSPECTION )
NG: REPAIR OR REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER

OK: Go to next step
READ VALUE USING TECHSTREAM (COOLANT TEMP) (See INSPECTION PROCEDURE )
NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See REMOVAL )

OK: Go to next step
READ VALUE USING TECHSTREAM (MAF) (See INSPECTION PROCEDURE )
NG: REPLACE MASS AIR FLOW METER (See REMOVAL )

OK: Go to next step

INSPECT 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.)

Fig 4: Identifying Spark Plug Electrode Gap
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the electrode for carbon deposits.

Recommended spark plug:

SPARK PLUG SPECIFICATION

Manufactures	Products
DENSO	SK16R11
NGK	IFR5A11

NOTE: If the electrode gap is out of 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 onto the ignition coil.
3. Attach the spark plug assembly to the cylinder head.
4. Crank the engine for less than 2 seconds and check the spark.
  OK:
  
  Sparks jump across electrode gap.
  
  Fig 5: Identifying Spark Plug For Sparks And Ignition
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Reconnect the injector connectors.
NG: Go to step 27

OK: Go to next step
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRE CYLINDER
1. Measure the cylinder compression pressure of the misfiring cylinder (See ON-VEHICLE INSPECTION ).
NG: CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK: Go to next step

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

Disconnect the C20 ECM connector.

Fig 6: Identifying C20 ECM Connector Terminals

Turn the ignition switch to ON.

Measure the voltage between the terminals of the ECM connector.

Standard voltage

TESTER CONNECTIONS SPECIFIED CONDITIONS CHART

Tester Connections	Specified Conditions
#10 (C20-108) - E01 (C20-45)	11 to 14 V
#20 (C20-107) - E01 (C20-45)
#30 (C20-106) - E01 (C20-45)
#40 (C20-105) - E01 (C20-45)

Reconnect the ECM connector.

NG: GO TO FUEL INJECTOR CIRCUIT

OK: Go to next step

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

OK: Go to next step
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER
1. Check the valve clearance of the misfiring cylinder (See ADJUSTMENT ).
NG: ADJUST VALVE CLEARANCE (See ADJUSTMENT )

OK: REPLACE ECM (See REMOVAL )
CHANGE TO 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 all injector connectors.
  
  NOTE: Do not crank the engine for more than 2 seconds.
  1. Install the spark plug into 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: Go to step 28

OK: REPLACE SPARK PLUG
CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER
1. Change the ignition coil to a ignition coil that functions normally.
2. Perform a spark test.
  CAUTION: Always disconnect all injector connectors.
  
  NOTE: Do not crank the engine for more than 2 seconds.
  1. Install the spark plug into 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 ECM (See REMOVAL )

OK: REPLACE IGNITION COIL (See REMOVAL )