P0301

3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0300: Random / Multiple Cylinder Misfire Detected

DTC P0300 - Random / Multiple Cylinder Misfire Detected

DTC P0301 - Cylinder 1 Misfire Detected

DTC P0302 - Cylinder 2 Misfire Detected

DTC P0303 - Cylinder 3 Misfire Detected

DTC P0304 - Cylinder 4 Misfire Detected

DTC P0305 - Cylinder 5 Misfire Detected

DTC P0306 - Cylinder 6 Misfire Detected

DESCRIPTION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emission levels. High concentrations of HC can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increases in emissions and to limit the possibility of thermal damage, the ECM (included in the hybrid vehicle control ECU) 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 exceeds the threshold levels, and could cause emission control system performance deterioration, the ECM illuminates the MIL and sets a DTC.

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

MONITOR DESCRIPTION

The ECM (included in the hybrid vehicle control ECU) illuminates the MIL and sets a DTC when either one of the following conditions, which could cause emission control system performance deterioration, is detected (2 trip detection logic).

- Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.
- After the first 1000 crankshaft revolutions, an excessive misfiring rate (approximately 20 to 60 misfires per 1000 crankshaft revolutions) occurs 4 times in sequential crankshaft revolutions.

The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).

- In every 200 crankshaft revolutions at a high engine rpm, the threshold misfiring percentage is recorded once.
- In every 200 crankshaft revolutions at a normal engine rpm, the threshold misfiring percentage is recorded 3 times.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Misfire:

Monitor period of emission-related misfire:

Monitor period of catalyst-damaging (MIL blinks):

TYPICAL MALFUNCTION THRESHOLDS

Monitor period of related misfire:

Monitor period of damaging misfire (MIL blinks):

MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Record the DTC(s) and freeze frame data.
5. Using the Techstream, switch the ECM (included in the hybrid vehicle control ECU) from normal mode to check mode Check Mode Procedure.
6. Read the misfire counts of each cylinder (Cylinder #1 Misfire Count to Cylinder #6 Misfire Count with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.)
7. Drive the vehicle several times with the conditions, such as engine rpm and engine load, shown in Misfire RPM and Misfire Load in the Data List.
HINT: In order to store misfire DTCs, it is necessary to drive the vehicle for the period of time shown in the table below, with the Misfire RPM and Misfire Load in the Data List.

8. Check whether misfires have occurred by checking the DTCs and freeze frame data.
HINT: Do not turn the power switch off until the stored DTC(s) and freeze data have been recorded. When the ECM (included in the hybrid vehicle control ECU) returns to normal mode (default), the stored DTC(s), freeze frame data and other data will be erased.

9. Record the DTC(s), freeze frame data and misfire counts.

INSPECTION PROCEDURE
HINT:
- If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
- Read freeze frame data using the Techstream. The ECM (included in the hybrid vehicle control ECU) 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 running or stopped, 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.
- After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfiring Count to Cylinder #6 Misfiring Count).
- 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 (included in the hybrid vehicle control ECU) intentionally does not set 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 DTCs 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 Techstream.
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), misfires have occurred while warming up the engine.
- An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be detected.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE DTCS)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs.
Result:

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

B -- GO TO DTC CHART
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the power switch on (IG) and turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire RPM and Misfire Load.
(e) 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.

NEXT -- Continue to next step.

3. CHECK PCV HOSE CONNECTIONS
OK:
PCV hose is connected correctly and is not damaged.

NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.

4. CHECK MISFIRE COUNT (CYL #1, #2, #3, #4, #5 AND #6)
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream on.
(d) Clear the DTCs.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count, #2, #3, #4, #5 and #6.
(f) Start the engine.
(g) Read each value of Cylinder #1 to #6 displayed on the tester. If no misfire counts occur in any cylinders, perform the following conditions:
(1) Shift the gear selector lever to the D position.
(2) Repeat steps (e) to (g) above.
(3) Check the Cylinder #1 Misfire Count to #6.
(4) If misfire counts are still not displayed, perform the following two steps and then check the misfire counts again.
(h) Drive the vehicle with Misfire RPM and Misfire Load noted in step 2.
(i) Read the Cylinder #1 Misfire Count to #6 or DTCs displayed on the Techstream.
Result:

B -- CHECK INTAKE SYSTEM
A -- Continue to next step.

5. CHECK SPARK PLUG

(a) Remove the ignition coil and the spark plug of the misfiring cylinder.
(b) Measure the spark plug electrode gap.
Standard:
Between 1.0 mm and 1.3 mm (0.039 in. and 0.051 in.)
(c) Check the electrode for carbon deposits.

Recommended spark plug:

NOTE: If the electrode gap is not as specified, replace the spark plug. Do not adjust the electrode gap.

NG -- REPLACE SPARK PLUG
OK -- Continue to next step.

6. CHECK FOR SPARK
(a) Disconnect the injector connectors to prevent the engine from starting.
CAUTION: Always disconnect all injector connectors.
NOTE: Do not crank the engine for more than 2 seconds.
(b) Remove the ignition coil from the cylinder head.
(c) Install the spark plug onto the ignition coil.
(d) Touch the spark plug tip to the cylinder head.
(e) Crank the engine for less than 2 seconds and check for spark.
OK:
Spark jumps across electrode gap.
(f) Install the ignition coil.
(g) Reconnect the injector connectors.

NG -- CHECK FUEL LINE
OK -- Continue to next step.

7. CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.

NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (INJECTOR OF MISFIRING CYLINDER POWER SOURCE)

(a) Disconnect the injector connectors (of the misfiring cylinder).
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(d) Reconnect the injector connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INJ NO. 2 FUSE - INJECTOR)
OK -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - FUEL INJECTOR)

(a) Disconnect the injector connectors.
(b) Disconnect the hybrid vehicle control ECU connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
Check for open

Check for short

(d) Reconnect the hybrid vehicle control ECU connectors.
(e) Reconnect the injector connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FUEL INJECTOR - HYBRID VEHICLE CONTROL ECU)
OK -- Continue to next step.

10. CHECK FUEL INJECTOR OF MISFIRING CYLINDER
(a) Check the injector resistance Testing and Inspection.
(b) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.

NG -- REPLACE FUEL INJECTOR ASSEMBLY
OK -- Continue to next step.

11. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks.
OK:
No leaks in intake system.

NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.

12. CHECK VALVE TIMING
(a) Check the valve timing Removal.

NG -- ADJUST VALVE TIMING
OK -- Continue to next step.

13. CHECK FUEL PRESSURE
(a) Check the fuel pressure Testing and Inspection.

NG -- CHECK FUEL LINE
OK -- Continue to next step.

14. READ VALUE USING TECHSTREAM (COOLANT TEMP)
(a) Check the engine coolant temperature Testing and Inspection.

NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
OK -- Continue to next step.

15. INSPECT MASS AIR FLOW METER
(a) Inspect the mass air flow meter Testing and Inspection.

NG -- REPLACE MASS AIR FLOW METER
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
16. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks Testing and Inspection.
OK:
No leaks in intake system.

NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.

17. CHECK VALVE TIMING
(a) Check the valve timing Removal.

NG -- ADJUST VALVE TIMING
OK -- Continue to next step.

18. CHECK FUEL PRESSURE
(a) Check the fuel pressure Testing and Inspection.

NG -- CHECK FUEL LINE
OK -- Continue to next step.

19. READ VALUE USING TECHSTREAM (COOLANT TEMP)
(a) Check the engine coolant temperature Testing and Inspection.

NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
OK -- Continue to next step.

20. INSPECT MASS AIR FLOW METER
(a) Inspect the mass air flow meter Testing and Inspection.

NG -- REPLACE MASS AIR FLOW METER
OK -- Continue to next step.

21. CHECK SPARK PLUG

(a) Remove the ignition coil and the spark plug of the misfiring cylinder.
(b) Measure the spark plug electrode gap.
Maximum gap:
Between 1.0 mm and 1.3 mm (0.039 in. and 0.051 in.)
(c) Check the electrode for carbon deposits.

Recommended spark plug:

NOTE: If the electrode gap is not as specified, replace the spark plug. Do not adjust the electrode gap.

NG -- REPLACE SPARK PLUG
OK -- Continue to next step.

22. CHECK FOR SPARK
(a) Disconnect the injector connectors to prevent the engine from starting.
CAUTION: Always disconnect all injector connectors.
NOTE: Do not crank the engine for more than 2 seconds.
(b) Remove the ignition coil from the cylinder head.
(c) Install the spark plug onto the ignition coil.
(d) Touch the spark plug tip to the cylinder head.
(e) Crank the engine for less than 2 seconds and check for spark.
OK:
Spark jumps across electrode gap.
(f) Install the ignition coil.
(g) Reconnect the injector connectors.

NG -- CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.

23. CHECK CYLINDER COMPRESSION PRESSURE
(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.

NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.

24. CHECK HARNESS AND CONNECTOR (INJECTOR OF MISFIRING CYLINDER POWER SOURCE)

(a) Disconnect the injector connectors (of the misfiring cylinder).
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:

(d) Reconnect the injector connectors.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (INJ NO. 2 FUSE - INJECTOR)
OK -- Continue to next step.

25. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - INJECTOR OF MISFIRING)

Check for short