Toyota Tundra Service Manual: Random / Multiple Cylinder Misfire Detected (P0300-P0308)

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 (TWC) temperature, which may cause damage to the TWC. 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 TWC reaches the point of thermal degradation, the MIL blinks. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted as when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire rate exceeds the threshold level, the ECM illuminates the MIL and stores a DTC.

When multiple DTCs for misfiring cylinders are 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.

MONITOR DESCRIPTION

The ECM illuminates the MIL and stores a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

• Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 10 to 50 misfires per 1000 crankshaft revolutions) occurs once.
• An excessive misfiring rate (approximately 10 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL (immediate detection logic) and stores a DTC (2 trip detection logic) when either one of the following conditions, which could cause Three-Way Catalytic Converter (TWC) damage, is detected (2 trip detection logic).

• At a high engine rpm, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected once.
• At a normal engine rpm, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.

HINT:

If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

MONITOR RESULT

Refer to Checking Monitor Status (See page ).

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Record the DTC(s) and freeze frame data.
5. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
6. Using the Techstream, switch the ECM from normal mode to check mode (See page ).
7. Read the misfire counts of each cylinder (cylinder No. 1 to No. 8) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.
8. Drive the vehicle several times with the conditions, such as engine rpm and engine load, as shown in Misfire RPM and Misfire Load in the freeze frame data.

   HINT:

   In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, with the engine speed and engine load the same as Misfire RPM and Misfire Load in the freeze frame data.

   Engine RPM	Duration
   Idling	8.0 minutes or more
   1000	4.5 minutes or more
   2000	2.5 minutes or more
   3000	1.5 minutes or more

9. 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.

10. Record the DTC(s), freeze frame data and misfire counts.
11. Turn the ignition switch off and wait for at least 5 seconds.
12. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

CAUTION / NOTICE / HINT

HINT:

• If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
• Read freeze frame data using the 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 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 may be a cause of the problem:
  1. The fuel level is low.
  2. Improper fuel is used.
  3. The spark plugs are dirty.
• After finishing repairs, check that no misfires occur in each cylinder (cylinder No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7 and No. 8).
• Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern after the repairs.
• For 6 and 8 cylinder engines, the ECM intentionally does not store the specific misfiring cylinder DTCs at high engine RPM. If misfires only occur during high engine RPM driving, only DTC P0300 is stored.

  In the event of DTC P0300 being present, perform the following operations:

  1. Clear the DTC (See page ).
  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 stored.
• When either Short FT B1S1, Long FT B1S1, Short FT B2S1 or Long FT B2S1 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 Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfires occurred only while warming up the engine.
• An extremely imbalanced drive wheel, which causes body vibration, may cause misfire DTCs to be detected.

PROCEDURE

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read DTCs.

HINT:

If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

(a) Check the PCV hose connections.

OK:

PCV hose is connected correctly and is not damaged.

NG

REPAIR OR REPLACE PCV HOSE

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) 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 values.

HINT:

The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Catalyst OT MF F/C.

(e) Read the value displayed on the Techstream.

B

GO TO STEP 6

A

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs (See page ).

(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Prohibit the Catalyst OT Misfire prevent F/C.

(f) Perform the Active Test.

NOTICE:

When performing the Active Test, make sure the vehicle is stopped and either idling or being revved within 3000 rpm.

NEXT

(a) Enter the following menus: Powertrain / Engine and ECT / Data List / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

(b) Allow the engine to idle.

(c) Read each value for Cylinder #1 Misfire Count to Cylinder #8 Misfire Count displayed on the Techstream. If no misfire counts occur in any cylinders, perform the following procedures:

(1) Move the shift lever to D.

(2) Check Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

(3) If misfire counts are still not displayed, perform procedure "A" and "B", and then check the misfire counts again.

Procedure A: Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read value using Techstream (Misfire RPM and Misfire Load)" procedures above.

Procedure B: Read Cylinder #1 Misfire Count to Cylinder #8 Misfire Count or DTCs displayed on the Techstream.

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 19

A

(a) Inspect the spark plug of the misfiring cylinder (See page ).

HINT:

Perform "Inspection After Repair" after replacing the spark plug (See page ).

NG

REPLACE SPARK PLUG

OK

(a) Perform the spark test (See page ).

HINT:

• If the result of the spark test is normal, proceed to the next step.
• Perform "Inspection After Repair" after replacing the ignition coil or the spark plug (See page ).

NEXT

(a) Measure the cylinder compression pressure of the misfiring cylinder (See page ).

HINT:

Perform "Inspection After Repair" after repairing or replacing the engine assembly (See page ).

NG

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:

NG

GO TO FUEL INJECTOR CIRCUIT

OK

(a) Check the injector injection [whether fuel volume is high or low, and whether injection pattern is poor] (See page ).

HINT:

Perform "Inspection After Repair" after replacing the fuel injector assembly (See page ).

NG

REPLACE FUEL INJECTOR ASSEMBLY

OK

(a) Check the intake system for vacuum leakage (See page ).

OK:

No leakage in intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system (See page ).

NG

REPAIR OR REPLACE INTAKE SYSTEM

OK

(a) Check the fuel pressure (See page ).

NG

GO TO STEP 36

OK

NG

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / MAF and Coolant Temp.

(e) Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

(f) Read the MAF with the engine speed at 3000 rpm.

Standard:

Between 18.3 gm/sec. and 25.8 gm/sec. (shift lever: N; A/C: Off)

NG

GO TO STEP 31

OK

NG

ADJUST VALVE TIMING

OK

(a) Connect the Techstream to the DLC3.

(b) Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

HINT:

• When performing the Active Test, make sure the shift lever is in P or N.
• The A/C switch and all accessory switches should be off.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

(e) Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

HINT:

• Do not leave the EGR valve open for 10 seconds or more during the Active Test.
• Be sure to return the EGR valve to step 0 when the Active Test is completed.

OK:

MAP and idling condition change in response to EGR step position as follows.

Standard:

OK

GO TO STEP 31

NG

(a) Remove the EGR valve assembly (See page ).

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

HINT:

Perform "Inspection After Repair" after replacing the EGR valve assembly (See page ).

OK

GO TO STEP 31

NG

REPLACE EGR VALVE ASSEMBLY

(a) Check the intake system for vacuum leakage (See page ).

OK:

No leakage in intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system (See page ).

NG

REPAIR OR REPLACE INTAKE SYSTEM

OK

(a) Check the fuel pressure (See page ).

NG

GO TO STEP 36

OK

NG

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / MAF and Coolant Temp.

(e) Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

(f) Read the MAF with the engine speed at 3000 rpm.

Standard:

Between 18.3 gm/sec. and 25.8 gm/sec. (shift lever: N; A/C: Off)

NG

GO TO STEP 31

OK

NG

ADJUST VALVE TIMING

OK

(a) Connect the Techstream to the DLC3.

(b) Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

HINT:

• When performing the Active Test, make sure the shift lever is in P or N.
• The A/C switch and all accessory switches should be off.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

(e) Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

HINT:

• Do not leave the EGR valve open for 10 seconds or more during the Active Test.
• Be sure to return the EGR valve to step 0 when the Active Test is completed.

OK:

MAP and idling condition change in response to EGR step position as follows.

Standard:

OK

GO TO STEP 31

NG

(a) Remove the EGR valve assembly (See page ).

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

HINT:

Perform "Inspection After Repair" after replacing the EGR valve assembly (See page ).

NG

REPLACE EGR VALVE ASSEMBLY

OK

(a) Inspect the spark plug of the misfiring cylinder (See page ).

HINT:

Perform "Inspection After Repair" after replacing the spark plug (See page ).

NG

REPLACE SPARK PLUG

OK

(a) Perform the spark test (See page ).

HINT:

• If the result of the spark test is normal, proceed to the next step.
• Perform "Inspection After Repair" after replacing the ignition coil or the spark plug (See page ).

NEXT

(a) Measure the cylinder compression pressure of the misfiring cylinder (See page ).

HINT:

Perform "Inspection After Repair" after repairing or replacing the engine assembly (See page ).

NG

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:

NG

GO TO FUEL INJECTOR CIRCUIT

OK

(a) Check the injector injection [whether fuel volume is high or low, and whether injection pattern is poor] (See page ).

HINT:

Perform "Inspection After Repair" after replacing the fuel injector assembly (See page ).

NG

REPLACE FUEL INJECTOR ASSEMBLY

OK

(a) Check the connection and terminal contact pressure of connectors and wire harness between the mass air flow meter and ECM (See page ).

HINT:

Repair any problems.

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTC (See page ).

(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Turn the ignition switch to ON and turn the Techstream on.

(g) Start the engine and warm it up.

(h) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(j) Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

(k) Check the DTC judgment result.

B

END

A

(a) Disconnect the MAF meter connector.

(b) Disconnect the ECM connector.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Replace the mass air flow meter (See page ).

HINT:

• If the results of the inspection performed in steps 15 and 22 indicates no problem, proceed to the next step without replacing the mass air flow meter assembly.
• Perform "Inspection After Repair" after replacing the mass air flow meter (See page ).

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTC (See page ).

(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Turn the ignition switch to ON and turn the Techstream on.

(g) Start the engine and warm it up.

(h) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(j) Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

(k) Check the DTC judgment result.

A

END

B

REPLACE ECM

(a) Check the fuel lines for leaks or blockage.

HINT:

Perform "Inspection After Repair" after replacing the fuel pump (See page ).

OK

REPLACE FUEL PUMP

NG

REPAIR OR REPLACE FUEL LINE