1Nz-Fe Engine Control. Dtc P0300 Random / Multiple Cylinder Misfire Detected

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause an increase in exhaust emission levels. Extremely 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 this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire count. 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 count exceeds the threshold levels, and could cause emission control system performance deterioration, the ECM illuminates the MIL and stores a DTC.

DTC No.	DTC Detection Condition	Trouble Area
P0300	Simultaneous misfiring of several cylinders occurs and one of the following conditions is met (2 trip detection logic): A misfire occurs that may damage the three-way catalytic converter (MIL blinks). An emission deterioration misfire occurs (MIL illuminates).	Open or short in engine wire harness Connector connection Vacuum hose connections Ignition system Fuel injector assembly Fuel pressure Mass air flow meter Engine coolant temperature sensor Compression pressure Valve timing PCV valve and hose PCV hose connections Intake system ECM
P0301 P0302 P0303 P0304	Misfiring of a specific cylinder occurs and one of the following conditions is met (2 trip detection logic): A misfire occurs that may damage the three-way catalytic converter (MIL blinks). An emission deterioration misfire occurs (MIL illuminates).

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.

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 after the engine starts, an excessive number of misfires (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.
An excessive number of misfires (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

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

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

Misfire Monitor for Mexico Models

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 after the engine starts, an excessive number of misfires (approximately 1000 misfires per 1000 crankshaft revolutions) occurs once.
An excessive number of misfires (approximately 500 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

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

A catalyst-damaging misfire, which is monitored every 200 crankshaft revolutions, occurs 3 times.

MONITOR STRATEGY

Related DTCs	P0300: Multiple Cylinder Misfire P0301: Cylinder 1 Misfire P0302: Cylinder 2 Misfire P0303: Cylinder 3 Misfire P0304: Cylinder 4 Misfire
Required Sensors/Components (Main)	Crankshaft position sensor Camshaft position sensor
Required Sensors/Components (Related)	Engine coolant temperature Intake air temperature sensor Mass air flow meter
Frequency of Operation	Continuous
Duration	1000 crankshaft revolutions (soon after engine is started: 1 time, other 4 times) (Emissions-related misfire) 200 crankshaft revolutions (1 or 3 times) (Catalyst-damaging misfire)
MIL Operation	2 driving cycles: Emission-related misfire MIL flashes immediately: Catalyst-damaging misfire
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Misfire
Monitor runs whenever following DTCs not present	P0016 (VVT System - Misalignment) P0102, P0103 (Mass Air Flow Meter) P0112, P0113 (Intake Air Temperature Sensor) P0115, P0117, P0118 (Engine Coolant Temperature Sensor) P0125 (Insufficient Coolant Temperature for Closed Loop Fuel Control) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor) P0327, P0328 (Knock Sensor) P0335 (Crankshaft Position Sensor) P0340 (Camshaft Position Sensor) P0351 - P0354 (Igniter) P0500 (Vehicle Speed Sensor) P0705 (Shift Lever Position Switch)
Battery voltage	8 V or higher
VVT system	Not operated by scan tool
Engine speed	450 to 6600 rpm
Either of following conditions (a) or (b) met	-
(a) Engine coolant temperature at engine start	Higher than -7°C (19°F)
(b) Engine coolant temperature	Higher than 20°C (68°F)
Fuel cut	OFF

Monitor Period of Emission-related Misfire
First 1000 revolutions after engine start, or during check mode	Crankshaft 1000 revolutions
Except above	Crankshaft 1000 revolutions x 4

Monitor Period of Catalyst-damaging Misfire (MIL Blinks)
All of following conditions 1, 2, 3 and 4 set	Crankshaft 200 revolutions x 3
Except above (MIL blinks immediately)	Crankshaft 200 revolutions
1. Driving cycles	1st
2. Check mode	OFF
3. Engine speed	Less than 2300 rpm
4. Intake air amount per revolution	Less than 0.6 g/rev

Misfire: for Mexico Models
Monitor runs whenever following DTCs not present	P0016 (VVT System - Misalignment) P0102, P0103 (Mass Air Flow Meter) P0112, P0113 (Intake Air Temperature Sensor) P0115, P0117, P0118 (Engine Coolant Temperature Sensor) P0125 (Insufficient Coolant Temperature for Closed Loop Fuel Control) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor) P0327, P0328 (Knock Control Sensor) P0335 (Crankshaft Position Sensor) P0340 (Camshaft Position Sensor) P0351 - P0354 (Igniter) P0500 (Vehicle Speed Sensor) P0705 (Shift Lever Position Switch)
Battery voltage	8 V or higher
VVT system	Not operated by scan tool
Engine speed	450 to 6600 rpm
Engine coolant temperature	Higher than 65°C (149°F)
Fuel cut	Off

Monitor Period of Emission-related Misfire: for Mexico Models
First 1000 revolutions after engine start, or check mode	Crankshaft 1000 revolutions
Except above	Crankshaft 1000 revolutions x 4

Monitor Period of Catalyst-damaging Misfire (MIL Blinks): for Mexico Models
Both of the following conditions 1 and 2 met:	Crankshaft 200 revolutions x 3
1. Driving cycles	1st
2. Check mode	Off
Except above (MIL blinks immediately)	Crankshaft 200 revolutions

TYPICAL MALFUNCTION THRESHOLDS

Monitor Period of Emission-related Misfire
Misfire rate	1.63% or more

Monitor Period of Catalyst-damaging Misfire (MIL Blinks)
Number of misfires per 200 revolutions	85 or more (varies with intake air amount and RPM)

Monitor Period of Emission-related Misfire: for Mexico Models
Misfire rate	50% or higher: for 1st 1000 revolutions 25% or higher: after 1st 1000 revolutions

Monitor Period of Catalyst-damaging Misfire (MIL Blinks): for Mexico Models
Number of misfires per 200 revolutions	85 or more (varies with intake air amount and engine speed)

MONITOR RESULT

Refer to detailed information in Checking Monitor Status (YARIS_NCP93 RM000000PDR0B4X.html).

P0300: Misfire / EWMA MISFIRE
Monitor ID	Test ID	Scaling	Unit	Description
$A1	$0B	Multiply by 1	Time	Total EWMA* misfire count of all cylinders in last ten driving cycles

P0300: Misfire / MISFIRE RATE
Monitor ID	Test ID	Scaling	Unit	Description
$A1	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of all cylinders in last driving cycle is displayed. While engine is running, total misfire count of all cylinders in current driving cycle is displayed.

P0301: Misfire / EWMA MISFIRE1
Monitor ID	Test ID	Scaling	Unit	Description
$A2	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 1 in last ten driving cycles

P0301: Misfire / MISFIRE RATE1
Monitor ID	Test ID	Scaling	Unit	Description
$A2	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 1 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 1 in current driving cycle is displayed.

P0302: Misfire / EWMA MISFIRE2
Monitor ID	Test ID	Scaling	Unit	Description
$A3	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 2 in last ten driving cycles

P0302: Misfire / MISFIRE RATE2
Monitor ID	Test ID	Scaling	Unit	Description
$A3	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 2 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 2 in current driving cycle is displayed.

P0303: Misfire / EWMA MISFIRE3
Monitor ID	Test ID	Scaling	Unit	Description
$A4	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 3 in last ten driving cycles

P0303: Misfire / MISFIRE RATE3
Monitor ID	Test ID	Scaling	Unit	Description
$A4	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 3 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 3 in current driving cycle is displayed.

P0304: Misfire / EWMA MISFIRE4
Monitor ID	Test ID	Scaling	Unit	Description
$A5	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 4 in last ten driving cycles

P0304: Misfire / MISFIRE RATE4
Monitor ID	Test ID	Scaling	Unit	Description
$A5	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 4 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 4 in current driving cycle is displayed.

HINT:

*: EWMA (Exponential Weighted Moving Average) misfire counts for last 10 driving cycles (calculated) Calculation: 0.1 x (current counts) + 0.9 x (previous average) Initial value for (previous average) = 0

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Record the DTC(s) and freeze frame data.
Clear DTCs (even if no DTCs are stored, perform the Clear DTC procedure).
Using the Techstream, switch the ECM from normal mode to check mode (YARIS_NCP93 RM000000PDL0L8X.html).
Read the misfire counts of each cylinder, Cylinder #1 Misfire Count to Cylinder #4 Misfire Count, with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.
Drive the vehicle so that the vehicle conditions displayed in Misfire RPM and Misfire Load of the Data List are the same as the freeze frame data. Perform this step several times.

HINT:
In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, confirm the Misfire RPM and Misfire Load in the Data List.

Engine speed
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
Check whether misfires have occurred by checking DTCs and freeze frame data.
HINT:
Do not turn the ignition switch off until the output 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 are cleared.
Record the DTC(s), freeze frame data and misfire counts.
Turn the ignition switch off and wait for at least 30 seconds.
Clear DTCs (even if no DTCs are stored, perform the Clear DTC procedure).

WIRING DIAGRAM

Refer to DTC P0102 for the mass air flow meter circuit (YARIS_NCP93 RM000000U5B0KEX_07.html).
Refer to Fuel Injector Circuit for the fuel injector circuit (YARIS_NCP93 RM000000ZRM0CSX_02.html).

INSPECTION PROCEDURE

NOTICE:

Inspect the fuses for circuits related to this system before performing the following 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 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 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:

There was insufficient fuel in the tank.
Improper fuel was used.
The spark plugs have been contaminated.
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 stored again by conducting the confirmation driving pattern after finishing repairs.
When one of Short FT #1 or Long FT #1 in the freeze frame data is outside the range of +/-15%, the air fuel ratio may be rich (-15% or less) or lean (+15% or more).
When Coolant Temp in the freeze frame data is below 75°C (167°F), the misfires have occurred only while warming up the engine.
An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored.

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

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Read 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

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.

GO TO DTC CHART (YARIS_NCP93 RM000000PDF0EWX.html)

A

2.CHECK PCV HOSE CONNECTIONS

Check the PCV hose connections (YARIS_NCP93 RM000001RN103YX.html).
OK:
PCV valve and hose are correctly connected and are not damaged.

REPAIR OR REPLACE PCV HOSE (YARIS_NCP93 RM000001RN204OX.html)

OK

3.READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream 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

4.READ VALUE USING TECHSTREAM (CATALYST OT MF F/C)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Read the value displayed on the Techstream.
Result
Data List
Techstream Display
Proceed to
Catalyst OT MF F/C
Avail
A
Not Avl
B

Result
Data List	Techstream Display	Proceed to
Catalyst OT MF F/C	Avail	A
Not Avl	B

Go to step 6

A

5.PERFORM ACTIVE TEST USING TECHSTREAM (PROHIBIT THE CATALYST OT MISFIRE PREVENT F/C)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

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

NEXT

6.READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT)

Enter the following menus: Powertrain / Engine and ECT / Data List / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count and Cylinder #4 Misfire Count.

Start the engine and allow the engine to idle.

Read each value for Cylinder #1 Misfire Count to Cylinder #4 Misfire Count displayed on the Techstream. If no misfire counts occur in any cylinders, perform following steps below and then check the misfire counts again.

Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read Value Using Techstream (Misfire RPM And Misfire Load)" procedures above.

Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the Techstream.
Result
Result
Proceed to
Most misfires occur in only 1 or 2 cylinders
A
3 cylinders or more have equal misfire counts
B

Result
Result	Proceed to
Most misfires occur in only 1 or 2 cylinders	A
3 cylinders or more have equal misfire counts	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 17

A

7.INSPECT SPARK PLUG

Inspect the spark plug of the misfiring cylinder (YARIS_NCP93 RM000001EFG05SX_01_0002.html).
HINT:
Perform "Inspection After Repair" after replacing the spark plug (YARIS_NCP93 RM000004NJD006X.html).

REPLACE SPARK PLUG (YARIS_NCP93 RM000002YO404IX.html)

OK

8.CHECK FOR SPARK (SPARK TEST)

Perform a spark test (YARIS_NCP93 RM000001EFG05SX_01_0003.html).
HINT:
1. If the result of the spark test is normal, proceed to the next step.
2. Perform "Inspection After Repair" after replacing the No. 1 ignition coil or the spark plug (YARIS_NCP93 RM000004NJD006X.html).

NEXT

9.CHECK CYLINDER COMPRESSION PRESSURE

Measure the cylinder compression pressure of the misfiring cylinder (YARIS_NCP93 RM000001DCF01PX_01_0008.html).
HINT:
Perform "Inspection After Repair" after repairing or replacing the engine assembly (YARIS_NCP93 RM000004NJD006X.html).

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

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

Yaris. Ncp93, 131.1Nz-Fe Engine Control.Sfi System (For Sedan).
Dtc
P0300 Random / Multiple Cylinder Misfire Detected

Disconnect the ECM connector.

Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
C51-20 (#10) - C51-51 (E01)	Ignition switch ON	11 to 14 V
C51-17 (#20) - C51-51 (E01)	Ignition switch ON	11 to 14 V
C51-18 (#30) - C51-51 (E01)	Ignition switch ON	11 to 14 V
C51-19 (#40) - C51-51 (E01)	Ignition switch ON	11 to 14 V

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

GO TO FUEL INJECTOR CIRCUIT (YARIS_NCP93 RM000000ZRM0CSX.html)

OK

11.CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

Check the fuel injector injection (whether fuel volume is high or low, and whether injection pattern is poor) (YARIS_NCP93 RM000001EDQ04MX.html).
HINT:
Perform "Inspection After Repair" after replacing the fuel injector assembly (YARIS_NCP93 RM000004NJD006X.html).

REPLACE FUEL INJECTOR ASSEMBLY (YARIS_NCP93 RM000001EDS04WX.html)

OK

12.CHECK INTAKE SYSTEM

Check the intake system for vacuum leaks (YARIS_NCP93 RM000004VL8003X.html).
OK:
No leaks from intake system.
HINT:
Perform "Inspection After Repair" after repairing or replacing the intake system (YARIS_NCP93 RM000004NJD006X.html).

REPAIR OR REPLACE INTAKE SYSTEM

OK

13.CHECK FUEL PRESSURE

Check the fuel pressure (YARIS_NCP93 RM000001IQZ080X_01_0002.html).

Go to step 32

OK

14.READ VALUE USING TECHSTREAM (COOLANT TEMP)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Read the Data List twice, when the engine is both cold and warmed up.

Standard:

Techstream Display
Condition
Specified Condition
Coolant Temp
Cold engine
Same as ambient air temperature
Warm engine
Between 75 and 100°C (167 and 212°F)

HINT:

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (YARIS_NCP93 RM000004NJD006X.html).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (YARIS_NCP93 RM000003VID00IX.html)

OK

15.READ VALUE USING TECHSTREAM (MAF)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

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

Read MAF with the engine speed at 3000 rpm.

Standard:

Techstream Display
Condition
Specified Condition
MAF
Shift lever position: N
A/C: Off
Engine Speed: 3000 rpm
Between 4 gm/sec. and 10 gm/sec.

Go to step 27

OK

16.CHECK VALVE TIMING

Remove the cylinder head cover.

Turn the crankshaft pulley, and align its groove with the timing mark "0" on the timing chain cover.

Check that the timing marks on the camshaft timing sprocket and camshaft timing gear are facing upward as shown in the illustration.
1. If not, turn the crankshaft 1 revolution (360°), then align the marks as above.
OK:
Timing marks on camshaft timing gears are aligned as shown in the illustration.
Text in Illustration
*a
Timing Marks (at top center of each gear)
*b
Timing Mark (groove on crankshaft pulley)

Go to step 27

ADJUST VALVE TIMING (YARIS_NCP93 RM000001DFR02KX.html)

17.CHECK INTAKE SYSTEM

Check the intake system for vacuum leaks (YARIS_NCP93 RM000004VL8003X.html).
OK:
No leaks from intake system.
HINT:
Perform "Inspection After Repair" after repairing or replacing the intake system (YARIS_NCP93 RM000004NJD006X.html).

REPAIR OR REPLACE INTAKE SYSTEM

OK

18.CHECK FUEL PRESSURE

Check the fuel pressure (YARIS_NCP93 RM000001IQZ080X_01_0002.html).

Go to step 32

OK

19.READ VALUE USING TECHSTREAM (COOLANT TEMP)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

Read the Data List twice, when the engine is both cold and warmed up.

Standard:

Techstream Display
Condition
Specified Condition
Coolant Temp
Cold engine
Same as ambient air temperature
Warm engine
Between 75 and 100°C (167 and 212°F)

HINT:

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (YARIS_NCP93 RM000004NJD006X.html).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (YARIS_NCP93 RM000003VID00IX.html)

OK

20.READ VALUE USING TECHSTREAM (MAF)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

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

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

Read MAF with the engine speed at 3000 rpm.

Standard:

Techstream Display
Condition
Specified Condition
MAF
Shift lever position: N
A/C: Off
Engine Speed: 3000 rpm
Between 4 gm/sec. and 10 gm/sec.

Go to step 27

OK

21.CHECK VALVE TIMING

Remove the cylinder head cover.

Turn the crankshaft pulley, and align its groove with the timing mark "0" on the timing chain cover.

Check that the timing marks on the camshaft timing sprocket and camshaft timing gear are facing upward as shown in the illustration.
1. If not, turn the crankshaft 1 revolution (360°), then align the marks as above.
OK:
Timing marks on camshaft timing gears are aligned as shown in the illustration.
Text in Illustration
*a
Timing Marks (at top center of each gear)
*b
Timing Mark (groove on crankshaft pulley)

ADJUST VALVE TIMING (YARIS_NCP93 RM000001DFR02KX.html)

OK

22.INSPECT SPARK PLUG

Inspect the spark plug of the misfiring cylinder (YARIS_NCP93 RM000001EFG05SX_01_0002.html).
HINT:
Perform "Inspection After Repair" after replacing the spark plug (YARIS_NCP93 RM000004NJD006X.html).

REPLACE SPARK PLUG (YARIS_NCP93 RM000002YO404IX.html)

OK

23.CHECK FOR SPARK (SPARK TEST)

Perform a spark test (YARIS_NCP93 RM000001EFG05SX_01_0003.html).
HINT:
1. If the result of the spark test is normal, proceed to the next step.
2. Perform "Inspection After Repair" after replacing the No. 1 ignition coil or the spark plug (YARIS_NCP93 RM000004NJD006X.html).

NEXT

24.CHECK CYLINDER COMPRESSION PRESSURE

Measure the cylinder compression pressure of the misfiring cylinder (YARIS_NCP93 RM000001DCF01PX_01_0008.html).
HINT:
Perform "Inspection After Repair" after repairing or replacing the engine assembly (YARIS_NCP93 RM000004NJD006X.html).

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

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

Disconnect the ECM connector.

Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
C51-20 (#10) - C51-51 (E01)	Ignition switch ON	11 to 14 V
C51-17 (#20) - C51-51 (E01)	Ignition switch ON	11 to 14 V
C51-18 (#30) - C51-51 (E01)	Ignition switch ON	11 to 14 V
C51-19 (#40) - C51-51 (E01)	Ignition switch ON	11 to 14 V

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

GO TO FUEL INJECTOR CIRCUIT (YARIS_NCP93 RM000000ZRM0CSX.html)

OK

26.CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

Check the fuel injector injection (whether fuel volume is high or low, and whether injection pattern is poor) (YARIS_NCP93 RM000001EDQ04MX.html).
HINT:
Perform "Inspection After Repair" after replacing the fuel injector assembly (YARIS_NCP93 RM000004NJD006X.html).

REPLACE FUEL INJECTOR ASSEMBLY (YARIS_NCP93 RM000001EDS04WX.html)

OK

27.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)

Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter and ECM (YARIS_NCP93 RM000000UZ309WX.html).
HINT:
Repair any problems.

NEXT

28.CHECK WHETHER DTC OUTPUT RECURS

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Clear the DTCs (YARIS_NCP93 RM000000PDK0T5X.html).

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

Turn the ignition switch to ON.

Turn the Techstream on.

Start the engine.

Warm up the engine.

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

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

Input the DTC: P0300, P0301, P0302, P0303 or P0304.

Check the DTC judgment result.
Result
Result
Proceed to
ABNORMAL
(P0300, P0301, P0302, P0303 or P0304 output)
A
NORMAL
(No DTC output)
B

END

A

29.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the mass air flow meter connector.

Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection
Condition
Specified Condition
C63-3 (VG) - C51-91 (VG)
Always
Below 1 Ω
C63-2 (E2G) - C51-92 (E2G)
Always
Below 1 Ω
C63-3 (VG) or C51-91 (VG) - Body ground
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

30.REPLACE MASS AIR FLOW METER

Replace the mass air flow meter (YARIS_NCP93 RM000003VI000HX.html).
HINT:
1. If the results of the inspections performed in steps 15 and 20 indicated no problem, proceed to the next step without replacing the mass air flow meter.
2. Perform "Inspection After Repair" after replacing the mass air flow meter (YARIS_NCP93 RM000004NJD006X.html).

NEXT

31.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Clear the DTCs (YARIS_NCP93 RM000000PDK0T5X.html).

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

Turn the ignition switch to ON.

Turn the Techstream on.

Start the engine.

Warm up the engine.

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

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

Input the DTC: P0300, P0301, P0302, P0303 or P0304.

Check the DTC judgment result.
Result
Result
Proceed to
NORMAL
(No DTC output)
A
ABNORMAL
(P0300, P0301, P0302, P0303 or P0304 output)
B

REPLACE ECM (YARIS_NCP93 RM000001CN002IX.html)

END

32.CHECK FUEL LINE

Check the fuel lines for leaks or blockage.
HINT:
Perform "Inspection After Repair" after replacing the fuel pump (YARIS_NCP93 RM000004NJD006X.html).

REPAIR OR REPLACE FUEL LINE

REPLACE FUEL PUMP (YARIS_NCP93 RM000004NLO00FX.html)

Engine speed	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

Techstream Display	Condition	Specified Condition
Coolant Temp	Cold engine	Same as ambient air temperature
Coolant Temp	Warm engine	Between 75 and 100°C (167 and 212°F)

*a	Timing Marks (at top center of each gear)
*b	Timing Mark (groove on crankshaft pulley)

Result	Proceed to
ABNORMAL (P0300, P0301, P0302, P0303 or P0304 output)	A
NORMAL (No DTC output)	B