Confirmation Driving Pattern

(a) Connect an intelligent tester to the DLC3.

(b) Turn the ignition switch ON.

(d) Record the DTC(s) and freeze frame data.

(e) Using the tester, switch the ECM from normal mode to check mode (See page ES-41).

(f) Read the misfire counts of each cylinder (CYL #1 to #6) with the engine in an idling condition. If any misfire count is displayed, skip the following confirmation driving pattern.

(g) 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.

Engine RPM

Duration

Idling

3.5 minutes or more

1,000

3 minutes or more

2,000

1.5 minutes or more

3,000

1 minute or more

(h) 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 erased.

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

(j) Turn the ignition switch OFF and wait for at least 5 seconds.

HINT:

• If any DTCs other than the misfire DTCs are output, troubleshoot those DTCs first.

• Read freeze frame data using an intelligent tester. Freeze frame data record the engine conditions 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.

• 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 (CYL #1, #2, #3, #4, #5 and #6).

• 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 intentionally does not set the 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:

(2) Start the engine and conduct the confirmation driving pattern.

(3) Read the misfiring rates of each cylinder or DTC(s) using the tester.

(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), the misfires have occurred only while warming up the engine.

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Post a comment