Part 2 of 2
Continued
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 records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
- 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, one of the following factors is considered to be a possible cause of the problem:
(1) There was insufficient fuel in the tank.
(2) Improper fuel is used.
(3) The spark plugs have been contaminated.
(4) The problem requires further diagnosis.
- After finishing repairs, check the misfire counts of the cylinders Cylinder #1 Misfire Count to Cylinder #4 Misfire Count.
- 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 #1or Long FT #1 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 below 75°C (167°F), the misfire has occurred only while warming up the engine.
- An extremely unbalanced drive wheel which causes body vibration may cause misfire DTCs detection.
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.
HINT
Write down the indicated DTCs.
Result
HINT
If any DTCs other than P0300, P0301, P0302, P0303 and/or P0304 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART SFI System
A -- Continue to next step.
2. CHECK PCV HOSE CONNECTIONS
(a) Check the PCV hose connections Intake System.
OK:
PCV hose is correctly connected and is not damaged.
NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.
3. READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)
(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 / Data List / Gas Misfire / 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 -- Continue to next step.
4. READ VALUE USING TECHSTREAM (CYLINDER #1 (TO #4) MISFIRE COUNT)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Misfire / Cylinder #1 (to #4) Misfire Count.
(g) Allow the engine to idle.
(h) Read each value for Cylinder #1 (to #4) Misfire Count displayed on the Techstream. If no misfire counts occur in any cylinders, perform steps [A] and [B], and then check the misfire counts again.
(i) Drive the vehicle with the Misfire RPM and Misfire Load noted in the read value using the Techstream (Misfire RPM and Misfire Load) procedures above [A].
(j) Read Cylinder #1 (to #4) Misfire Count or the DTCs displayed on the Techstream [B].
Result
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), it may only be possible to detect the misfire when the engine is cold.
B -- CHECK INTAKE SYSTEM
A -- Continue to next step.
5. INSPECT SPARK PLUG
(a) Inspect the spark plug Testing and Inspection.
NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.
6. CHECK FOR SPARKS AND IGNITION
(a) Perform spark test Testing and Inspection.
CAUTION:
Always disconnect all fuel injector assembly connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Spark jumps across electrode gap.
NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.
7. CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
(a) Measure the cylinder compression pressure of the misfiring cylinder On-Vehicle Inspection.
NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.
8. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE VOLTAGE) Fuel Injector Circuit
NG -- GO TO FUEL INJECTOR CIRCUIT Fuel Injector Circuit
OK -- Continue to next step.
9. CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM) Fuel Injector Circuit
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
10. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER
(a) Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.
NG -- REPLACE FUEL INJECTOR ASSEMBLY Removal
OK -- Continue to next step.
11. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks Intake System.
OK:
No leakage in intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.
12. CHECK FUEL PRESSURE
(a) Check the fuel pressure Fuel System.
NG -- CHECK FUEL LINE
OK -- Continue to next step.
13. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
14. READ VALUE USING TECHSTREAM (MAF) P0171
NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.
15. ADJUST VALVE TIMING P0011
NEXT -- Continue to next step.
16. CHECK WHETHER DTC OUTPUT RECURS (P0300, P0301, P0302, P0303 OR P0304)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Drive the vehicle accordance with the driving pattern described in Confirmation Driving Pattern.
(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
(f) Read the pending DTCs.
Result
B -- END
A -- Continue to next step.
17. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.
(e) Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
HINT
The A/C switch and all accessory switches should be off.
(f) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / Primary / Throttle Idle Position and MAP.
(g) Confirm that 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.
- Do not open the EGR valve 30 steps or more during the Active Test.
OK:
MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.
Standard:
HINT
During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.
NG -- INSPECT EGR VALVE ASSEMBLY
OK -- CHECK HARNESS AND CONNECTOR
18. INSPECT EGR VALVE ASSEMBLY
(a) Remove the EGR valve assembly Removal.
(b) Check if the EGR valve is stuck open.
OK:
EGR valve is tightly closed.
NG -- REPLACE EGR VALVE ASSEMBLY Removal
OK -- CHECK HARNESS AND CONNECTOR
19. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks Intake System.
OK:
No leaks in intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.
20. CHECK FUEL PRESSURE
(a) Check the fuel pressure Fuel System.
NG -- CHECK FUEL LINE
OK -- Continue to next step.
21. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
22. READ VALUE USING TECHSTREAM (MAF) P0171
NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.
23. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE EGR STEP POSITION)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.
(e) Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
HINT
The A/C switch and all accessory switches should be off.
(f) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / Primary / Throttle Idle Position and MAP.
(g) Confirm that 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.
- Do not open the EGR valve 30 steps or more during the Active Test.
OK:
MAP and idling condition change in response to EGR step position when Throttle Idle Position is ON in Data List.
Standard:
HINT
During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.
NG -- INSPECT EGR VALVE ASSEMBLY
OK -- CHECK HARNESS AND CONNECTOR
24. INSPECT EGR VALVE ASSEMBLY
(a) Remove the EGR valve assembly Removal.
(b) Check if the EGR valve is stuck open.
OK:
EGR valve is tightly closed.
NG -- REPLACE EGR VALVE ASSEMBLY Removal
OK -- Continue to next step.
25. INSPECT SPARK PLUG
(a) Inspect the spark plug Testing and Inspection.
NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.
26. CHECK FOR SPARKS AND IGNITION
(a) Perform spark test Testing and Inspection.
CAUTION:
Always disconnect all fuel injector assembly connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Spark jumps across electrode gap.
NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.
27. CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
(a) Measure the cylinder compression pressure of the misfiring cylinder On-Vehicle Inspection.
NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.
28. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE) Fuel Injector Circuit
NG -- CHECK FUEL INJECTOR CIRCUIT Fuel Injector Circuit
OK -- Continue to next step.
29. CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY- ECM) Fuel Injector Circuit
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
30. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER
(a) Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.
NG -- REPLACE FUEL INJECTOR ASSEMBLY Removal
OK -- Continue to next step.
31. ADJUST VALVE TIMING P0011
NEXT -- Continue to next step.
32. CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Drive the vehicle accordance with the driving pattern described in Confirmation Driving Pattern.
(e) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
(f) Read the pending DTCs.
Result
B -- END
A -- Continue to next step.
33. CHECK HARNESS AND CONNECTOR
(a) Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM Electronic Circuit Inspection Procedure.
HINT
Repair any problems.
NEXT -- Continue to next step.
34. CHECK WHETHER DTC OUTPUT RECURS
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Turn the power switch off and wait for 30 seconds.
(f) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
(g) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(h) Input the DTC: P0300, P0301, P0302, P0303 or P0304.
(i) Check the DTC judgment result.
Result
B -- END
A -- Continue to next step.
35. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
(a) Disconnect the mass air flow meter sub-assembly 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 -- Continue to next step.
36. REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
(a) Replace the mass air flow meter sub-assembly Removal.
HINT
If the results of the inspections performed in steps 14 and 22 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
NEXT -- Continue to next step.
37. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Turn the power switch off and wait for 30 seconds.
(f) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
(g) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(h) Input the DTC: P0300, P0301, P0302, P0303 or P0304.
(i) Check the DTC judgment result.
Result
B -- REPLACE ECM Removal
A -- END
38. CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
(a) Change the installed spark plug to a spark plug that functions normally.
(b) Perform a spark test Testing and Inspection.
CAUTION:
Always disconnect all fuel injector assembly connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Spark jumps across electrode gap.
NG -- CHANGE TO NORMAL IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER
OK -- REPLACE SPARK PLUG Removal
39. CHANGE TO NORMAL IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER
(a) Change the ignition coil assembly to an ignition coil assembly that functions normally.
(b) Perform a spark test Testing and Inspection.
CAUTION:
Always disconnect all fuel injector assembly connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Spark jumps across electrode gap.
NG -- REPLACE ECM Removal
OK -- REPLACE IGNITION COIL ASSEMBLY Removal
40. CHECK FUEL LINE
(a) Check the fuel lines for leaks or blockage.
NG -- REPAIR OR REPLACE FUEL LINE
OK -- REPLACE FUEL PUMP Removal