Lexus NX: Bank 1 Air-Fuel Ratio Imbalance (P219A,P219C-P219F)

Lexus NX Service Manual / Engine & Hybrid System / 2ar-fxe (engine Control) / Sfi System / Bank 1 Air-Fuel Ratio Imbalance (P219A,P219C-P219F)

DESCRIPTION

Refer to DTC P0300.

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Refer to DTC P2195.

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P219A	Bank 1 Air-Fuel Ratio Imbalance	The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic).	Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P219C	Cylinder 1 Air-Fuel Ratio Imbalance	The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic).	Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P219D	Cylinder 2 Air-Fuel Ratio Imbalance	The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic).	Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P219E	Cylinder 3 Air-Fuel Ratio Imbalance	The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic).	Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P219F	Cylinder 4 Air-Fuel Ratio Imbalance	The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic).	Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored

MONITOR DESCRIPTION

Fuel System Air Fuel Ratio Cylinder Imbalance Monitor

The ECM uses the air fuel ratio sensor and crankshaft position sensor to monitor the difference in air fuel ratios between the cylinders caused by differences in injection volumes between the cylinders, leakage in the intake or exhaust system, etc.

When the air fuel ratios of the cylinders are lean or rich with respect to each other, the ECM determines that there is a malfunction, illuminates the MIL and stores a DTC.

Air Fuel Ratio Sensor Monitoring Method: P219A is stored primarily when a rich side imbalance is detected.

When the system detects a difference in air fuel ratios between the cylinders due to fluctuation in the air fuel ratio sensor output over 1 engine cycle (2 crankshaft revolutions), the ECM determines that there is a malfunction.

Crankshaft Position Sensor Monitoring Method: P219C, P219D, P219E and/or P219F are stored primarily when a lean side imbalance is detected.

The system monitors the engine speed variation and when the variation becomes large, the ECM determines that there is a difference in air fuel ratios between the cylinders, which it determines to be a malfunction.

MONITOR STRATEGY

Related DTCs	P219A: Air fuel ratio cylinder imbalance monitor P219C: Air fuel ratio cylinder imbalance monitor (cylinder 1) P219D: Air fuel ratio cylinder imbalance monitor (cylinder 2) P219E: Air fuel ratio cylinder imbalance monitor (cylinder 3) P219F: Air fuel ratio cylinder imbalance monitor (cylinder 4)
Required Sensors/Components (Main)	Air fuel ratio sensor Crankshaft position sensor
Required Sensors/Components (Related)	Mass air flow meter sub-assembly Engine coolant temperature sensor
Frequency of Operation	Once per driving cycle
Duration	10 to 15 seconds
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

P219A, P219C, P219D, P219E and P219F

Monitor runs whenever the following DTCs are not stored

P0010 (Camshaft timing oil control valve)

P0011 (VVT system - advance)

P0012 (VVT system - retard)

P0016 (VVT system - misalignment)

P0031, P0032, P101D (Air fuel ratio sensor heater)

P0102, P0103 (Mass air flow meter)

P0107, P0108 (Manifold absolute pressure)

P0115, P0117, P0118 (Engine coolant temperature sensor)

P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle position sensor)

P0125 (Insufficient coolant temperature for closed loop fuel control)

P0335 (Crankshaft position sensor)

P0340 (Camshaft position sensor)

P0340, P0342, P0343 (VVT sensor)

P0351, P0352, P0353, P0354 (Igniter)

P0401 (EGR system)

P219A: Air Fuel Ratio Sensor Monitoring Method

Air fuel ratio sensor status	Activated
Engine speed	2200 rpm or more, and less than 2800 rpm
Engine coolant temperature	73°C (163°F) or higher
Atmospheric pressure	76 kPa(abs) [570 mmHg(abs)] or higher
Fuel system status	Closed loop
Mass air flow	22 g/sec or more, and less than 44 g/sec

P219C, P219D, P219E and P219F: Crankshaft Position Sensor Monitoring Method (First Judgment)

Engine speed	2000 rpm or more, and less than 2400 rpm
Engine Load	40% or more, and less than 60%
Engine coolant temperature	73°C (163°F) or higher
Air fuel ratio sensor status	Activated
Fuel system status	Closed loop
Auxiliary battery voltage	11 V or higher

P219C, P219D, P219E and P219F: Crankshaft Position Sensor Monitoring Method (Second Judgment)

Vehicle speed	Less than 3 km/h (1.875 mph)
Engine speed	1050 rpm or more, and less than 1350 rpm
Engine coolant temperature	73°C (163°F) or higher
Air fuel ratio sensor status	Activated
Fuel system status	Closed loop
Auxiliary battery voltage	11 V or higher

TYPICAL MALFUNCTION THRESHOLDS

P219A: Air Fuel Ratio Sensor Monitoring Method (Bank 1)

Air fuel ratio sensor monitoring method criteria

0.075 or more

Crankshaft Position Sensor Monitoring Method (First Judgment)

Crankshaft position sensor monitoring method criteria (first judgment)

1.5 or more

Crankshaft Position Sensor Monitoring Method (Second Judgment)

Crankshaft position sensor monitoring method criteria (second judgment)

1 or more

HINT:

If the first judgment while driving shows that the value of Engine Speed Fluctuation Average is between 0.5 and 1.5, then second judgment will be performed when the vehicle is stopped and the engine is idling.

MONITOR RESULT

Refer to detailed information in Checking Monitor Status.

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P219A: Fuel System / A/F SENSOR DETERMINATION B1

Monitor ID	Test ID	Scaling	Unit	Description
$81	$81	Multiply by 0.00003	No dimension	Monitoring method using air fuel ratio sensor

P219C: Fuel System / ENGINE SPEED FLUCTUATION AVERAGE #1

Monitor ID	Test ID	Scaling	Unit	Description
$81	$85	Multiply by 0.001	No dimension	Monitoring method using crank angle sensor

P219D: Fuel System / ENGINE SPEED FLUCTUATION AVERAGE #2

Monitor ID	Test ID	Scaling	Unit	Description
$81	$86	Multiply by 0.001	No dimension	Monitoring method using crank angle sensor

P219E: Fuel System / ENGINE SPEED FLUCTUATION AVERAGE #3

Monitor ID	Test ID	Scaling	Unit	Description
$81	$87	Multiply by 0.001	No dimension	Monitoring method using crank angle sensor

P219F: Fuel System / ENGINE SPEED FLUCTUATION AVERAGE #4

Monitor ID	Test ID	Scaling	Unit	Description
$81	$88	Multiply by 0.001	No dimension	Monitoring method using crank angle sensor

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Put the engine in inspection mode (maintenance mode).
Click here
Start the engine and warm it up until the engine coolant temperature reaches 73°C (163°F) or higher [A].
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
NOTICE:

Use the Techstream to clear the DTCs. (Do not disconnect the cable from negative (-) auxiliary battery terminal to clear the DTCs.)
With the engine running, drive the vehicle at 40 km/h (25 mph) or higher.
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

If the engine stops, further depress the accelerator pedal to restart the engine.
With the engine running, gradually accelerate the vehicle from 40 km/h (25 mph) to 80 km/h (50 mph) taking approximately 10 to 20 seconds [B].
HINT:
- Refer to mass air flow and engine speed in Typical Enabling Conditions, and then accelerate the vehicle to 80 km/h (50 mph).
- If the engine stops, further depress the accelerator pedal to restart the engine.
With the engine running, drive the vehicle at 80 km/h (50 mph) or higher for 1 minute or more [C].
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
- Electrical load can be applied while the vehicle is driven.
- If the engine stops, further depress the accelerator pedal to restart the engine.
Idle the engine for 1 minute or more [D].
HINT:

With the shift lever in D.
Repeat steps [B] and [D] above at least 3 times [E].
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [F].
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
With the engine running, drive the vehicle at 80 km/h (50 mph).
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

HINT:

If the engine stops, further depress the accelerator pedal to restart the engine.
With the engine running, gradually accelerate the vehicle from 80 km/h (50 mph) to 100 km/h (62 mph) taking approximately 5 to 15 seconds [G].
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
- Refer to mass air flow and engine speed in Typical Enabling Conditions, and then accelerate the vehicle to 100 km/h (62 mph).
- If the engine stops, further depress the accelerator pedal to restart the engine.
With the engine running, drive the vehicle at 100 km/h (62 mph) or higher for 1 minute or more [H].
CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
HINT:
- Electrical load can be applied while the vehicle is driven.
- If the engine stops, further depress the accelerator pedal to restart the engine.
Idle the engine for 1 minute or more [I].
HINT:

With the shift lever in D.
Repeat steps [G] and [I] above at least 2 times [J].
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [K].
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P219A, P219C, P219D, P219E or P219F.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE, perform the confirmation driving pattern and check the judgment result again.
If the judgment result shows N/A, perform the following procedure.

If no pending DTC is output, perform a universal trip and check for permanent DTCs.
Click here
HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

CAUTION / NOTICE / HINT

HINT:

Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
When any air-fuel ratio imbalance is detected, the ECM will perform air-fuel ratio feedback control to make the air-fuel ratio close to the stoichiometric level. This may result in an air-fuel ratio imbalance of normal cylinders and DTCs may be stored.
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.

PROCEDURE

1.	CHECK ANY OTHER DTCS OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

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

(e) Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result	Proceed to
DTC P219A, P219C, P219D, P219E and/or P219F is output	A
DTC P219A, P219C, P219D, P219E and/or P219F and other DTCs are output	B

HINT:

If any DTCs other than DTC P219A, P219C, P219D, P219E and/or P219F are output, troubleshoot those DTCs first.

GO TO DTC CHART

2.	READ VALUE USING TECHSTREAM (FREEZE FRAME DATA)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and turn the Techstream on.

(c) Using the Techstream, confirm the vehicle conditions recorded in the freeze frame data which were present when the DTC was stored.

Click here

Freeze Frame Data Items for DTC P219A, P219C, P219D, P219E or P219F:

Vehicle Speed
Engine Speed
Calculate Load
Short FT
Long FT
Cylinder #1 Misfire Count to Cylinder #4 Misfire Count

HINT:

When the sum of Short FT and Long FT is positive, the engine is running lean, and when the sum is negative, the engine is running rich.

Air Fuel Ratio Sensor Monitoring Method (P219A)	Crankshaft Position Sensor Monitoring Method (P219C, P219D, P219E and P219F)	Note
DTCs are output	DTC is output (Only one DTC relating to a single cylinder is output)	Malfunctioning of cylinders detected by Crankshaft Position Sensor Monitoring Method is primarily suspected
DTCs are output	DTCs are output (Multiple DTCs relating to multiple cylinders are output)	Malfunctioning of cylinders except ones detected by Crankshaft Position Sensor Monitoring Method is primarily suspected.*
DTCs are not output	DTCs are output	Malfunctioning of cylinders detected by Crankshaft Position Sensor Monitoring Method is primarily suspected.
DTCs are output	DTCs are not output	Malfunctioning of the bank detected by Air Fuel Ratio Sensor Monitoring Method is primarily suspected.

*: When any air-fuel ratio imbalance is detected, the ECM will perform air-fuel ratio feedback control to make the air-fuel ratio close to the stoichiometric level. This may result in an air-fuel ratio imbalance of normal cylinders and DTCs may be stored.

3.	READ DTC OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

(e) Start the engine.

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

HINT:

If any misfire count ("Cylinder #1 Misfire Count" to "Cylinder #4 Misfire Count) increases while idling or driving the vehicle, proceed to step 6.
Perform inspections while focusing on the cylinder whose misfire count has increased.

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

(h) Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result	Proceed to
DTC P219A is output	A
DTC P219A and P219C, P219D or P219E are output	B
DTC P219C, P219D, P219E and/or P219F is output	B

GO TO STEP 6

4.	PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Put the engine in inspection mode (maintenance mode).

Click here

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

(e) Start the engine and warm it up.

HINT:

The A/C switch and all accessory switches should be off and the shift lever should be in P or N.

(f) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / Gas Misfire / Cylinder #1 to #4 Misfire Count.

Powertrain > Engine and ECT > Active Test

Active Test Display
Control the Injection Volume

Data List Display
Cylinder #1 Misfire Count
Cylinder #2 Misfire Count
Cylinder #3 Misfire Count
Cylinder #4 Misfire Count

HINT:

When the "Control the Injection Volume" Active Test is selected (injection volume is 0%), if a misfire count increases, proceed to step 6 (Check Intake System).

(g) Perform the Control the Injection Volume operation with the engine idling.

(h) Check the misfire counts ("Cylinder #1 Misfire Count" to "Cylinder #4 Misfire Count") while decreasing the injection volume in 5% increments.

NOTICE:

Do not decrease the injection volume by higher than 20%.

The cylinder whose misfire count has not increased can be assumed to be running rich. Therefore, perform inspections while focusing on that cylinder.

5.	CHECK FOR EXHAUST GAS LEAK

(a) Check for exhaust gas leaks.

OK:

No gas leaks.

HINT:

Perform "Inspection After Repair" after repairing or replacing the exhaust system.

Click here

REPAIR OR REPLACE EXHAUST SYSTEM

6.	CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leaks.

Click here

OK:

No leaks in the intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system.

Click here

REPAIR OR REPLACE INTAKE SYSTEM

7.	INSPECT SPARK PLUG

(a) Inspect the spark plug of the cylinder causing the imbalance.

Click here

HINT:

Perform "Inspection After Repair" after replacing the spark plug.

Click here

REPLACE SPARK PLUG

8.	CHECK FOR SPARK (SPARK TEST)

(a) Perform a spark test.

Click here

HINT:

If the result of the spark test is normal, proceed to the next step.
Perform "Inspection After Repair" after replacing the spark plug or ignition coil assembly.
Click here

9.	CHECK CYLINDER COMPRESSION PRESSURE

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

Click here

HINT:

Perform "Inspection After Repair" after repairing or replacing the engine assembly.

Click here

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

10.	CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL INJECTOR ASSEMBLY)

Click here

CHECK FUEL INJECTOR CIRCUIT

11.	CHECK FUEL INJECTOR ASSEMBLY OF CYLINDER CAUSING IMBALANCE

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

Click here

HINT:

Perform "Inspection After Repair" after replacing the fuel injector assembly.

Click here

REPLACE FUEL INJECTOR ASSEMBLY

12.	CHECK FOR CAUSE OF FAILURE

(a) If the cause of the problem has not been found even after performing the troubleshooting procedure, perform the inspection below.

(b) Check the intake valve for deposits.

HINT:

As the DTC may have been stored due to deposits on the intake valve, remove the cylinder head and check the intake valves.

HINT:

The DTC may have been stored due to deposits that have accumulated in the EGR delivery chamber. Therefore, remove and inspect the EGR delivery chamber.

13.	CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Clear the DTCs.

Click here

Powertrain > Engine and ECT > Clear DTCs

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

(f) Turn the power switch on (IG).

(g) Turn the Techstream on.

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

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

(j) Check for DTCs.

Powertrain > Engine and ECT > Trouble Codes

DTCs are not output.

END

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