Lexus NX: Ignition Coil "A" Primary / Secondary Circuit (P0351-P0354)

Lexus NX Service Manual / Engine & Hybrid System / 2ar-fxe (engine Control) / Sfi System / Ignition Coil "A" Primary / Secondary Circuit (P0351-P0354)

DESCRIPTION

HINT:

These DTCs indicate malfunctions relating to the primary circuit.
If DTC P0351 is output, check the No. 1 ignition coil assembly (No. 1 cylinder) circuit.
If DTC P0352 is output, check the No. 2 ignition coil assembly (No. 2 cylinder) circuit.
If DTC P0353 is output, check the No. 3 ignition coil assembly (No. 3 cylinder) circuit.
If DTC P0354 is output, check the No. 4 ignition coil assembly (No. 4 cylinder) circuit.

A Direct Ignition System (DIS) is used on this vehicle.

The DIS is a 1-cylinder ignition system in which each cylinder is ignited by one ignition coil assembly and one spark plug is connected to the end of each secondary wiring. A powerful voltage, generated in the secondary wiring, is applied directly to each spark plug. The spark of the spark plugs passes from the center electrode to the ground electrodes.

The ECM determines the ignition timing and transmits the ignition (IGT) signals to each cylinder. Using the IGT signal, the ECM turns the power transistor inside the igniter on and off. The power transistor, in turn, switches the current supplied to the primary coil on and off. When the current to the primary coil is cut off, a powerful voltage is generated in the secondary coil. This voltage is applied to the spark plugs, causing them to spark inside the cylinders. As the ECM cuts the current to the primary coil, the igniter sends back an ignition confirmation (IGF1) signal to the ECM, for each cylinder ignition.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0351	Ignition Coil "A" Primary / Secondary Circuit	No IGF1 signal to ECM while the engine is running (1 trip detection logic).	Ignition system Open or short in IGF1 or IGT1 circuit between ignition coil assembly and ECM No. 1 ignition coil assembly IG2-MAIN relay ECM	Comes on	DTC stored
P0352	Ignition Coil "B" Primary / Secondary Circuit	No IGF1 signal to ECM while the engine is running (1 trip detection logic).	Ignition system Open or short in IGF1 or IGT2 circuit between ignition coil assembly and ECM No. 2 ignition coil assembly IG2-MAIN relay ECM	Comes on	DTC stored
P0353	Ignition Coil "C" Primary / Secondary Circuit	No IGF1 signal to ECM while the engine is running (1 trip detection logic).	Ignition system Open or short in IGF1 or IGT3 circuit between ignition coil assembly and ECM No. 3 ignition coil assembly IG2-MAIN relay ECM	Comes on	DTC stored
P0354	Ignition Coil "D" Primary / Secondary Circuit	No IGF1 signal to ECM while the engine is running (1 trip detection logic).	Ignition system Open or short in IGF1 or IGT4 circuit between ignition coil assembly and ECM No. 4 ignition coil assembly IG2-MAIN relay ECM	Comes on	DTC stored

Reference: Inspection using an oscilloscope

HINT:

While idling the engine, check the waveform between terminals IGT (1 to 4) and E1, and IGF1 and E1 of the ECM connector.

ECM Terminal Name

IGT: Between IGT (1 to 4) and E1

IGF: Between IGF1 and E1

Tester Range

2 V/DIV., 20 ms./DIV.

Condition

Idling with warm engine

MONITOR DESCRIPTION

If the ECM does not receive any IGF1 signals despite transmitting the IGT signal, it interprets this as a fault in the igniter and stores a DTC.

MONITOR STRATEGY

Related DTCs	P0351: Igniter (cylinder 1) circuit/open P0352: Igniter (cylinder 2) circuit/open P0353: Igniter (cylinder 3) circuit/open P0354: Igniter (cylinder 4) circuit/open
Required Sensors/Components (Main)	Igniter (Cylinder 1 to 4)
Required Sensors/Components (Related)	Crankshaft position sensor
Frequency of Operation	Continuous
Duration	-
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored	None
All of the following conditions are met	-
Spark cut	Not operating
Either of the following conditions is met	A or B
A. Starter	Off
B. Engine speed	1500 rpm or less
Either of the following conditions is met	C or D
C. Both of the following conditions are met	-
Engine speed	500 rpm or less
Auxiliary battery voltage	6 V or higher
D. All of the following conditions are met	-
Engine speed	Higher than 500 rpm
Auxiliary battery voltage	10 V or higher
Number of sparks after CPU is reset	5 sparks or more
Lost communication with hybrid vehicle control ECU (U0293)	Not detected
Hybrid control module judge	Engine running

TYPICAL MALFUNCTION THRESHOLDS

All of the following conditions are met	A, B, C and D
A. Ignition signal fail counter	More than 2 times
B. Time after condition A is met	0.256 seconds or more
C. Ignition signal fail counter after condition B is met	More than 2 times
D. Power switch	On (IG)

COMPONENT OPERATING RANGE

Confirmed ignition signal input

2 times or more

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the Techstream on.
Put the engine in inspection mode (maintenance mode).
Click here
Start the engine.
Idle the engine for 10 seconds or more [A].
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].
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: P0351, P0352, P0353 or P0354.

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 or N/A, perform steps [A] and [B] again.

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.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

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.	READ OUTPUT DTCS (DTC P0351, P0352, P0353 OR P0354)

(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) Shuffle the arrangement of the ignition coil assemblies (among No. 1 to No. 4 cylinders).

NOTICE:

Do not change the location of the connectors.

(g) Perform a simulation test.

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

(i) Read the DTCs.

Powertrain > Engine and ECT > Trouble Codes

Result	Proceed to
Same DTC output	A
Different ignition coil DTC output	B

HINT:

Perform "Inspection After Repair" after replacing the ignition coil assembly.

Click here

REPLACE IGNITION COIL ASSEMBLY

2.	CHECK HARNESS AND CONNECTOR (IGNITION COIL ASSEMBLY - BODY GROUND)

(a) Disconnect the ignition coil assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C9-4 (GND) - Body ground	Always	Below 1 Ω
C8-4 (GND) - Body ground	Always	Below 1 Ω
C7-4 (GND) - Body ground	Always	Below 1 Ω
C6-4 (GND) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	CHECK TERMINAL VOLTAGE (POWER SOURCE OF IGNITION COIL ASSEMBLY)

*a	Front view of wire harness connector (to Ignition Coil Assembly)

(a) Disconnect the ignition coil assembly connector.

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
C9-1 (+B) - C9-4 (GND)	Power switch on (IG)	11 to 14 V
C8-1 (+B) - C8-4 (GND)	Power switch on (IG)	11 to 14 V
C7-1 (+B) - C7-4 (GND)	Power switch on (IG)	11 to 14 V
C6-1 (+B) - C6-4 (GND)	Power switch on (IG)	11 to 14 V

GO TO STEP 5

4.	CHECK HARNESS AND CONNECTOR (IGNITION COIL ASSEMBLY - ECM)

(a) Disconnect the ignition coil assembly connector.

(b) Disconnect the ECM connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C9-3 (IGT1) - C48-57 (IGT1)	Always	Below 1 Ω
C8-3 (IGT2) - C48-56 (IGT2)	Always	Below 1 Ω
C7-3 (IGT3) - C48-55 (IGT3)	Always	Below 1 Ω
C6-3 (IGT4) - C48-54 (IGT4)	Always	Below 1 Ω
C9-2 (IGF) - C48-51 (IGF1)	Always	Below 1 Ω
C8-2 (IGF) - C48-51 (IGF1)	Always	Below 1 Ω
C7-2 (IGF) - C48-51 (IGF1)	Always	Below 1 Ω
C6-2 (IGF) - C48-51 (IGF1)	Always	Below 1 Ω
C9-3 (IGT1) or C48-57 (IGT1) - Body ground	Always	10 kΩ or higher
C8-3 (IGT2) or C48-56 (IGT2) - Body ground	Always	10 kΩ or higher
C7-3 (IGT3) or C48-55 (IGT3) - Body ground	Always	10 kΩ or higher
C6-3 (IGT4) or C48-54 (IGT4) - Body ground	Always	10 kΩ or higher
C9-2 (IGF) or C48-51 (IGF1) - Body ground	Always	10 kΩ or higher
C8-2 (IGF) or C48-51 (IGF1) - Body ground	Always	10 kΩ or higher
C7-2 (IGF) or C48-51 (IGF1) - Body ground	Always	10 kΩ or higher
C6-2 (IGF) or C48-51 (IGF1) - Body ground	Always	10 kΩ or higher

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK HARNESS AND CONNECTOR (IGNITION COIL ASSEMBLY - IG2-MAIN RELAY)

(a) Disconnect the ignition coil assembly connector.

(b) Remove the IG2-MAIN relay from the No. 1 engine room relay block and junction block assembly.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C9-1 (+B) - 5 (IG2-MAIN relay)	Always	Below 1 Ω
C8-1 (+B) - 5 (IG2-MAIN relay)	Always	Below 1 Ω
C7-1 (+B) - 5 (IG2-MAIN relay)	Always	Below 1 Ω
C6-1 (+B) - 5 (IG2-MAIN relay)	Always	Below 1 Ω
C9-1 (+B) or 5 (IG2-MAIN relay) - Body ground	Always	10 kΩ or higher
C8-1 (+B) or 5 (IG2-MAIN relay) - Body ground	Always	10 kΩ or higher
C7-1 (+B) or 5 (IG2-MAIN relay) - Body ground	Always	10 kΩ or higher
C6-1 (+B) or 5 (IG2-MAIN relay) - Body ground	Always	10 kΩ or higher

GO TO ECM POWER SOURCE CIRCUIT

REPAIR OR REPLACE HARNESS OR CONNECTOR

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