The actuator in the injector, which operates the nozzle needle, is a piezo type to allow high-speed operation. This high speed injector allows a two stage injection to reduce combustion noise, and allow high power output.

An injector consists of a nozzle needle, two pistons, three-way valve and a piezo actuator.

An injector compensation value and QR (Quick Response) code containing encoded characteristics of the individual injector are printed on each injector.

The injector compensation value and QR code contain various pieces of information regarding the injector, such as model code, and injection volume correction.

The ECM detects combustion deterioration for each specific cylinder.

HINT:

A cylinder which has an injection volume compensation value that differs from other cylinders may be malfunctioning.

If DTC P0093 (Fuel leaks in high-pressure area) is present simultaneously, a leak from the injector for the affected cylinder probably has occurred.

If DTC P0200 (Open or short in EDU or injector circuit) is present simultaneously, there probably is a fault in the circuit between the ECM and the injector. This fault may also be in the EDU.

If only DTC P1238 (Injector malfunction) is present, the probable cause is an injector mechanical malfunction or insufficient compression (valve etc), not an open or short malfunction of the ECM, EDU and injector circuit.

The solenoid valve of the injector is the same type as that of the pressure discharge valve.

Dtc P1238 Injector Malfunction. 2AD-FHV ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

DTC No.	DTC Detection Condition	Main Trouble Area	Related Trouble Area
P1238	Engine speed fluctuation is large when idling (2 trip detection logic)	Injector EDU (P0200 is set simultaneously) Open or short in engine wire harness (P0200 is set simultaneously) Connector connection (P0200 is set simultaneously) Compression pressure Valve clearance	Valve timing ECM

HINT:

After confirming DTC P1238, check the internal fuel pressure in "Powertrain / Engine / Data List / Fuel Press" using the intelligent tester.

Reference:
Engine Speed	Fuel Pressure (MPa)
Idling	Approximately 37 to 43
2,500 rpm (No engine load)	Approximately 60 to 66

MONITOR DESCRIPTION

P1238 (Injection malfunction, except open or short in injector circuit):

This DTC will be set if the engine speed fluctuation between each cylinder is large. The ECM monitors changes in the crankshaft rotation speed using the crankshaft position sensor in order to detect improper combustion. The camshaft position sensor also plays a role in determining which cylinder has the problem. The fluctuation counter increments when irregular crankshaft rotation speed variation exceeds the threshold with the engine idling. Therefore, if any one of the cylinders is operating poorly (rough idle), the ECM sets this DTC.

MONITOR STRATEGY

Required Sensors	Crankshaft position sensor
Frequency of operation	Continuous
Duration	10 minutes
CHK ENG operation	2 driving cycles

TYPICAL ENABLING CONDITIONS

Item	Specification
Item	Minimum	Maximum
Engine	At idling
Engine speed	700 rpm	-
Engine coolant temperature	20°C (68°F)	-

TYPICAL MALFUNCTION THRESHOLDS

Threshold

The number of irregular changes in the crankshaft rotation speed

HINT:

The number of irregular changes in the crankshaft rotation speed indicates the insufficient combustion.

WIRING DIAGRAM

Dtc P1238 Injector Malfunction. 2AD-FHV ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

NOTICE:

After replacing an injector, the ECM needs registration .

HINT:

If DTCs other than P1238 are present simultaneously, first perform troubleshooting for those DTCs.

1.CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P1238)

Connect the intelligent tester to the DLC3.

Turn the engine switch ON (IG) and turn the intelligent tester ON.

Enter the following menus: "Powertrain / Engine / DTC".

Read DTCs.

Result:
Display (DTC output) Proceed to
P1238 A
P1238 and other DTCs B

HINT:

If any other codes besides P1238 are output, perform troubleshooting for those DTCs first.

Go to step 5

A

4.PERFORM ACTIVE TEST BY INTELLIGENT TESTER (INJECTION CUT FOR IDENTIFYING MALFUNCTION CYLINDER)

Connect the intelligent tester to the DLC3.

Start the engine.

Turn the intelligent tester ON.

Enter the following menus: "Powertrain / Engine / Active Test / Control the Cylinder #1 (to #4) Fuel Cut".

Check the four cylinders in sequence to identify a faulty cylinder by performing the power-balance inspection.

HINT:

If the engine idle does not change when an injector is disabled, the cylinder being tested is malfunctioning.

NEXT

5.CHECK CYLINDER COMPRESSION PRESSURE (MALFUNCTIONING CYLINDER)

Check the cylinder compression pressure .

Standard:
2,700 kPa (27.5 kgf/cm², 392 psi)
Minimum pressure:
2,200 kPa (22.4 kgf/cm², 319 psi)
Difference between each cylinder:
500 kPa (5.1 kgf/cm², 73 psi)

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

6.CHECK IF DTC OUTPUT RECURS (DTC P1238)

HINT:

After clearing the DTC, let the engine idle for 10 minutes after warm-up, and then confirm that P1238 is not present again.

CHECK FOR INTERMITTENT PROBLEMS

NG

7.REPLACE INJECTOR ASSEMBLY

CHECK IF DTC OUTPUT RECURS (DTC P1238)

LEXUS IS250, IS220d / GSE20 ALE20

2AD-FHV ENGINE CONTROL SYSTEM

Lexus IS250 IS220d GSE20 ALE20

ECD SYSTEM