3Zr-Fae Engine Control System. Dtc P0300 Random / Multiple Cylinder Misfire Detected

When the engine misfires, high concentrations of hydrocarbons enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause increases in exhaust emission levels. High concentrations of hydrocarbons can also cause increases in the three way catalytic converter temperature, which may cause damage to the three way catalytic converter. To prevent these increases in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the three way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds.
If the misfire rate exceeds the threshold level and could cause emission deterioration, the ECM illuminates the MIL and stores a DTC.

DTC No.	DTC Detection Condition	Trouble Area
P0300	Simultaneous misfiring of several cylinders is detected (2 trip detection logic).	Open or short in engine wire harness Connector connection Vacuum hose connections Ignition system Injector Fuel pressure Mass air flow meter Engine coolant temperature sensor Compression pressure Valve timing PCV valve and hose PCV hose connection Intake system ECM
P0301 P0302 P0303 P0304	Misfiring of a specific cylinder is detected (2 trip detection logic).

When DTCs for misfiring cylinders are randomly stored, but DTC P0300 is not stored, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only stored when several misfiring cylinders are detected at the same time.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester on.
Record the DTC(s) and freeze frame data.
Using the tester, switch the ECM from normal mode to check mode (RAV4_ACA30 RM000000PDL0A2X.html).
Read the misfire counts of each cylinder (Cylinder #1 to #4) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.
If no misfire counts are displayed, drive the vehicle several times at the engine speed and engine load recorded in the freeze frame data.

HINT:
1. In order to detect misfire DTCs, drive the vehicle at the engine speed and engine load recorded in the freeze frame data for the time specified in the table below.
Engine Speed
Duration
Idling
8 minutes or more
1000
4 minutes 30 seconds or more
2000
2 minutes 30 seconds or more
3000
1 minute 30 seconds or more
Check whether misfires have occurred by checking DTCs and freeze frame data.
HINT:
Do not turn the ignition switch off until the stored DTC(s) and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTC(s), freeze frame data and other data will be cleared.
Record the DTC(s), freeze frame data and misfire counts.
Turn the ignition switch off and wait for 5 seconds.

INSPECTION PROCEDURE

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:

Check "Fuel Cut Elps Time" in the Data List or the Freeze Frame Data. If the elapsed time is over 0sec, then the engine speed is high (rpm at which fuel cut occurs +500 rpm). When this has happened, there is a possibility that the valve rocker arm will become loose and a fire could start, so check that the valve rocker arm is properly attached (RAV4_ACA30 RM0000027IB05UX.html).
By clearing the DTC, "Fuel Cut Elps Time" will be cleared.
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 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.
If 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:

The fuel level is low.
Improper fuel is used.
The spark plugs are dirty.
The problem is complex and involves multiple factors.

After finishing repairs, check that no misfire occurs in each cylinder (Cylinder #1, #2, #3 and #4).
Be sure to confirm that no misfiring cylinder DTCs are output again by conducting the confirmation driving pattern after the repairs.
When either the Short FT #1 or Long FT #1 value in the freeze frame data is not within 20% of the central value, 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 below 75°C (167°F), the misfires occurred only while warming up the engine.

1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE CODES)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.

Result
Result
Proceed to
DTC P0300, P0301, P0302, P0303 and/or P0304 are output
A
DTC P0300, P0301, P0302, P0303 and/or P0304 and other DTCs are output
B
HINT:
If any DTCs other than P0300, P0301, P0302, P0303 and P0304 are output, troubleshoot those DTCs first.

Result
Result	Proceed to
DTC P0300, P0301, P0302, P0303 and/or P0304 are output	A
DTC P0300, P0301, P0302, P0303 and/or P0304 and other DTCs are output	B

GO TO DTC CHART (RAV4_ACA30 RM000000PDF0FMX.html)

A

2.READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON and turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire RPM and Misfire Load.

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.

NEXT

3.CHECK PCV HOSE CONNECTIONS

Check the PCV hose connections.
OK:
PCV hose is correctly connected and is not damaged.

REPAIR OR REPLACE PCV HOSE

OK

4.READ VALUE USING INTELLIGENT TESTER (MISFIRE COUNT)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Cylinder #1 (to #4) Misfire Count.

Drive the vehicle at the engine speed and engine load noted in the "Read Value Using Intelligent Tester (Misfire RPM and Misfire Load)" procedure above.

Read Cylinder #1 (to #4) Misfire Count or the DTCs displayed on the tester.

Result
Misfire Count	Proceed to
Most misfires occur in only 1 or 2 cylinders, or misfire DTCs for only 1 or 2 cylinders are output	A
3 cylinders or more have equal misfire counts, or misfire DTCs for 3 or more cylinders are output	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 record of the engine coolant temperature is below 75°C (167°F), the misfire may be detected only when the engine is cold.
If the freeze frame data record of the Engine Run Time is below 120 seconds, the misfire may be detected immediately after the engine is started.

Go to step 18

A

5.CHECK SPARK PLUG

Check the spark plug (RAV4_ACA30 RM000001EFG02EX_01_0002.html).

REPLACE SPARK PLUG (RAV4_ACA30 RM000002YO400WX.html)

OK

6.CHECK FOR SPARK AND IGNITION

Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35

Perform a spark test.
CAUTION:
During the test, disconnect all the fuel injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
1. Remove the ignition coil from the cylinder head.
2. Install the spark plug to the ignition coil.
3. Disconnect the 4 fuel injector connectors.
4. Touch the spark plug assembly to the cylinder head.
5. Crank the engine for less than 2 seconds and check for sparks.
  OK:
  Sparks jump across electrode gap.
6. Reconnect the 4 fuel injector connectors.
7. Install the ignition coil.

Go to step 31

OK

7.CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER

Measure the cylinder compression pressure of the misfiring cylinder (RAV4_ACA30 RM000002ZLZ00OX_01_0010.html).

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

8.CHECK INJECTOR ASSEMBLY (POWER SOURCE)

Disconnect the injector assembly connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
B16-1 - Body ground	Ignition switch ON	11 to 14 V
B15-1 - Body ground	Ignition switch ON	11 to 14 V
B14-1 - Body ground	Ignition switch ON	11 to 14 V
B13-1 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration
*1	Front view of wire harness connector (to Fuel Injector)

Reconnect the injector assembly connector.

CHECK FUEL INJECTOR CIRCUIT (RAV4_ACA30 RM000000ZRM03ZX.html)

OK

9.CHECK HARNESS AND CONNECTOR (INJECTOR ASSEMBLY - ECM)

Disconnect the injector assembly connector.

Disconnect the ECM connector.

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

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
B16-2 - B32-86 (#10)	Always	Below 1 Ω
B15-2 - B32-85 (#20)	Always	Below 1 Ω
B14-2 - B32-84 (#30)	Always	Below 1 Ω
B13-2 - B32-83 (#40)	Always	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
B16-2 or B32-86 (#10) - Body ground	Always	10 kΩ or higher
B15-2 or B32-85 (#20) - Body ground	Always	10 kΩ or higher
B14-2 or B32-84 (#30) - Body ground	Always	10 kΩ or higher
B13-2 or B32-83 (#40) - Body ground	Always	10 kΩ or higher

Text in Illustration
*1	Front view of wire harness connector (to Fuel Injector)
*2	Front view of wire harness connector (to ECM)

Reconnect the injector connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (INJECTOR ASSEMBLY - ECM)

OK

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

Disconnect the ECM connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
B32-86 (#10) - B32-46 (E01)	Ignition switch ON	11 to 14 V
B32-85 (#20) - B32-46 (E01)	Ignition switch ON	11 to 14 V
B32-84 (#30) - B32-46 (E01)	Ignition switch ON	11 to 14 V
B32-83 (#40) - B32-46 (E01)	Ignition switch ON	11 to 14 V

Text in Illustration
*1	Front view of wire harness connector (to ECM)

Reconnect the ECM connector.

Go to step 33

OK

11.CHECK FUEL INJECTOR OF MISFIRING CYLINDER

Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) (RAV4_ACA30 RM000001EDQ01NX.html).

REPLACE FUEL INJECTOR ASSEMBLY (RAV4_ACA30 RM000001EDS01DX.html)

OK

12.CHECK INTAKE SYSTEM

Check the intake system for vacuum leakage (RAV4_ACA30 RM00000341000BX.html).
OK:
No leakage from intake system.

REPAIR OR REPLACE INTAKE SYSTEM

OK

13.CHECK FUEL PRESSURE

Check the fuel pressure (RAV4_ACA30 RM000001IQZ02QX_01_0002.html).

Go to step 34

OK

14.READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Read the Coolant Temp twice, when the engine is both cold and warmed up.
Standard temperature:
With cold engine:
Same as ambient air temperature.
With warm engine:
Between 75°C and 95°C (167°F and 203°F).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (RAV4_ACA30 RM000002WSG02VX.html)

OK

15.INSPECT MASS AIR FLOW METER

Inspect the mass air flow meter (RAV4_ACA30 RM000000Q2D046X.html).

REPLACE MASS AIR FLOW METER (RAV4_ACA30 RM000002WQT00SX.html)

OK

16.ADJUST VALVE TIMING

HINT:

There are no marks on the cylinder head to align for the purpose of checking valve timing. Valve timing can only be inspected by aligning the colored plates on the timing chain with the marks on the pulleys. It may be necessary to remove and reinstall the chain to align the timing marks (RAV4_ACA30 RM0000027I905UX_03_0377.html).

NEXT

17.CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 AND/OR P0304)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Clear the DTCs (RAV4_ACA30 RM000000PDK0WCX.html).

Start the engine and warm it up.

Switch the ECM from normal mode to check mode using the tester.

Run the engine at an engine speed of 1000 rpm for 4 minutes 30 seconds.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.
Result
Result
Proceed to
DTC is not output
A
DTC P0300, P0301, P0302, P0303 and/or P0304 are output
B

REPLACE ECM (RAV4_ACA30 RM0000017UO01KX.html)

SYSTEM IS OK

18.CHECK INTAKE SYSTEM

Check the intake system for vacuum leakage (RAV4_ACA30 RM00000341000BX.html).
OK:
No leakage from intake system.

REPAIR OR REPLACE INTAKE SYSTEM

OK

19.CHECK FUEL PRESSURE

Check the fuel pressure (RAV4_ACA30 RM000001IQZ02QX_01_0002.html).

Go to step 34

OK

20.READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Read the Coolant Temp twice, when the engine is both cold and warmed up.
Standard temperature:
With cold engine:
Same as ambient air temperature.
With warm engine:
Between 75°C and 95°C (167°F and 203°F).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (RAV4_ACA30 RM000002WSG02VX.html)

OK

21.INSPECT MASS AIR FLOW METER

Inspect the mass air flow meter (RAV4_ACA30 RM000000VA5015X.html).

REPLACE MASS AIR FLOW METER (RAV4_ACA30 RM000002WQT00SX.html)

OK

22.ADJUST VALVE TIMING

HINT:

NEXT

23.CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 AND/OR P0304)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Clear the DTCs (RAV4_ACA30 RM000000PDK0WCX.html).

Start the engine and warm it up.

Switch the ECM from normal mode to check mode using the tester.

Run the engine at an engine speed of 1000 rpm for 4 minutes 30 seconds.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.
Result
Result
Proceed to
DTC is not output
A
DTC P0300, P0301, P0302, P0303 and/or P0304 is output
B

Go to step 24

SYSTEM IS OK

24.CHECK SPARK PLUG

Check the spark plug (RAV4_ACA30 RM000001EFG02EX_01_0002.html).

REPLACE SPARK PLUG (RAV4_ACA30 RM000002YO400WX.html)

OK

25.CHECK FOR SPARK AND IGNITION (SPARK TEST)

Perform a spark test.
CAUTION:
During the test, disconnect all fuel injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
1. Remove the ignition coil from the cylinder head.
2. Install the spark plug to the ignition coil.
3. Disconnect the 4 fuel injector connectors.
4. Touch the spark plug assembly to the cylinder head.
5. Crank the engine for less than 2 seconds and check for sparks.
  OK:
  Sparks jump across electrode gap.
6. Reconnect the 4 fuel injector connectors.
7. Install the ignition coil.

Go to step 31

OK

26.CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER

Measure the cylinder compression pressure of the misfiring cylinder (RAV4_ACA30 RM000002ZLZ00OX_01_0010.html).

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

27.CHECK INJECTOR ASSEMBLY (POWER SOURCE)

Disconnect the injector assembly connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
B16-1 - Body ground	Ignition switch ON	11 to 14 V
B15-1 - Body ground	Ignition switch ON	11 to 14 V
B14-1 - Body ground	Ignition switch ON	11 to 14 V
B13-1 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration
*1	Front view of wire harness connector (to Fuel Injector)

Reconnect the injector assembly connector.

CHECK FUEL INJECTOR CIRCUIT (RAV4_ACA30 RM000000ZRM03ZX.html)

OK

28.CHECK HARNESS AND CONNECTOR (INJECTOR ASSEMBLY - ECM)

Disconnect the injector assembly connector.

Disconnect the ECM connector.

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

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
B16-2 - B32-86 (#10)	Always	Below 1 Ω
B15-2 - B32-85 (#20)	Always	Below 1 Ω
B14-2 - B32-84 (#30)	Always	Below 1 Ω
B13-2 - B32-83 (#40)	Always	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
B16-2 or B32-86 (#10) - Body ground	Always	10 kΩ or higher
B15-2 or B32-85 (#20) - Body ground	Always	10 kΩ or higher
B14-2 or B32-84 (#30) - Body ground	Always	10 kΩ or higher
B13-2 or B32-83 (#40) - Body ground	Always	10 kΩ or higher

Text in Illustration
*1	Front view of wire harness connector (to Fuel Injector)
*2	Front view of wire harness connector (to ECM)

Reconnect the injector connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (INJECTOR ASSEMBLY - ECM)

OK

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

Disconnect the ECM connector.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
B32-86 (#10) - B32-46 (E01)	Ignition switch ON	11 to 14 V
B32-85 (#20) - B32-46 (E01)	Ignition switch ON	11 to 14 V
B32-84 (#30) - B32-46 (E01)	Ignition switch ON	11 to 14 V
B32-83 (#40) - B32-46 (E01)	Ignition switch ON	11 to 14 V

Text in Illustration
*1	Front view of wire harness connector (to ECM)

Reconnect the ECM connector.

Go to step 33

OK

30.CHECK FUEL INJECTOR OF MISFIRING CYLINDER

Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) (RAV4_ACA30 RM000001EDQ01NX.html).

REPLACE FUEL INJECTOR ASSEMBLY (RAV4_ACA30 RM000001EDS01DX.html)

REPLACE ECM (RAV4_ACA30 RM0000017UO01KX.html)

31.REPLACE SPARK PLUG WITH NORMAL ONE AND CHECK SPARK OF MISFIRING CYLINDER

Replace the installed spark plug with a spark plug that functions normally.

Perform a spark test.
CAUTION:
During the test, disconnect all the injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
1. Install the spark plug to the ignition coil.
2. Disconnect the 4 fuel injector connectors.
3. Touch the spark plug assembly to the cylinder head.
4. Crank the engine for less than 2 seconds and check for sparks.
  OK:
  Sparks jump across electrode gap.

Go to step 32

REPLACE SPARK PLUG (RAV4_ACA30 RM000002YO400WX.html)

32.REPLACE IGNITION COIL WITH NORMAL ONE AND CHECK SPARK OF MISFIRING CYLINDER

Replace the ignition coil with an ignition coil that functions normally.

Perform a spark test.
CAUTION:
Always disconnect all the injector connectors.
NOTICE:
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 4 fuel injector connectors.
3. Touch the spark plug assembly to the cylinder head.
4. Crank the engine for less than 2 seconds and check for sparks.
  OK:
  Sparks jump across electrode gap.

REPLACE ECM (RAV4_ACA30 RM0000017UO01KX.html)

REPLACE IGNITION COIL (RAV4_ACA30 RM000002YO400WX.html)

33.CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
B32-46 (E01) - Body ground
Always
Below 1 Ω
B32-45 (E02) - Body ground
Always
Below 1 Ω
Text in Illustration
*1
Front view of wire harness connector
(to ECM)

REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

REPLACE FUEL INJECTOR ASSEMBLY (RAV4_ACA30 RM000001EDS01DX.html)

34.CHECK FUEL LINE

Check the fuel lines for leaks or blockage (RAV4_ACA30 RM000001EEZ00XX.html).

REPAIR OR REPLACE FUEL LINE

REPLACE FUEL PUMP ASSEMBLY (RAV4_ACA30 RM0000017RJ032X.html)

Engine Speed	Duration
Idling	8 minutes or more
1000	4 minutes 30 seconds or more
2000	2 minutes 30 seconds or more
3000	1 minute 30 seconds or more

Result	Proceed to
DTC is not output	A
DTC P0300, P0301, P0302, P0303 and/or P0304 are output	B