Engine Controls - Basic Diagnostic Procedures: Other Lexus LX J100

Compression

Warm engine to normal operating temperature before checking the compression. Ensure battery is fully charged. Remove ignition coils and spark plugs. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Check engine mechanical condition with a compression gauge, vacuum gauge, or engine analyzer with throttle fully open. See engine analyzer manual for specific instructions. See COMPRESSION SPECIFICATIONS table. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).

COMPRESSION SPECIFICATIONS

FUEL SYSTEM

Basic diagnosis of fuel system should begin by checking fuel pump operation and fuel pressure.

LX470

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-2759-S41214404652000041300000). Disconnect negative battery cable.
2. Remove cover located on top of engine, above intake manifold. Engine cover must be removed for access front fuel pipe at front of driver's side fuel rail. (Scheme 15)
3. Remove union bolt with gaskets, and disconnect front fuel pipe from front of driver's side fuel rail. It may be necessary to remove retaining bolt at center of front fuel pipe when disconnecting front fuel pipe from driver's side fuel rail.
4. Install Union (SST 90405-06167), Adapter (SST 09268-41190) and fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45014) with front fuel pipe on driver's side fuel rail. (Scheme 16) Tighten adapter to 29 ft. lbs. (39 N.m).
5. Install negative battery cable. Connect scan tool to Data Link Connector (DLC) No. 3, located under left side of instrument panel. Turn ignition on. DO NOT start engine.
6. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm 2 ). NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 6
7. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted near center of passenger's side fuel rail. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
8. Remove scan tool from DLC No. 3. Start engine. Disconnect and plug vacuum hose at fuel pressure regulator mounted near center of passenger's side fuel rail. Note fuel pressure with engine idling. Fuel pressure should be should be 38-44 psi (2.7-3.1 kg/cm 2 ).
9. Reinstall vacuum hose on fuel pressure regulator. Note fuel pressure with engine idling. Fuel pressure should be 28-34 psi (2.0-2.4 kg/cm 2 ). If fuel pressure is within specification, go to next step. If fuel pressure is not within specification, check for defective vacuum hose or fuel pressure regulator.
10. Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure holds as specified, go to next step. If fuel pressure does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
11. Release fuel pressure. Disconnect negative battery cable. Remove union, adapter and fuel pressure gauge from driver's side fuel rail. Using NEW gaskets, install front fuel pipe on driver's side fuel rail. Tighten union bolt to 29 ft. lbs. (39 N.m) and retaining bolt for front fuel pipe (if loosened) to 66 INCH lbs. (7.5 N.m).
12. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump. Install engine cover.

Scheme 15

Scheme 16

Scheme 17

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-2759-S41214404652000041300000). Disconnect negative battery cable.
2. Purchase a No. 1 fuel pipe Part No. (23801-20040) from parts department. No. 1 fuel pipe is fuel pipe that fits between fuel rails and fuel inlet pipe. (Scheme 17) Remove fuel pipe connector from end of NEW No. 1 fuel pipe. see scheme 10
3. Remove fuel pipe clamp from No. 1 fuel pipe at fuel inlet pipe. (Scheme 17) Ensure area around No. 1 fuel pipe and fuel inlet pipe is clean.
4. Depress both sides of retainer and pull No. 1 fuel pipe with disconnect fitting from fuel inlet pipe. (Scheme 18)
5. Install Adapter (SST 09268-41250), hose and fuel pressure gauge from Fuel Pressure Gauge Set (SST 09268-45012) with fuel pipe connector between No. 1 fuel pipe and fuel inlet pipe. (Scheme 19) Ensure hose, No. 1 fuel pipe and fuel pipe connector are properly connected.
6. Install negative battery cable. Connect scan tool to Data Link Connector (DLC) No. 3, located under left side of instrument panel. Turn ignition on. DO NOT start engine.
7. Turn scan tool on. Select ACTIVE TEST MODE on scan tool. Using scan tool manufacturer's instructions, activate fuel pump and note fuel pressure. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ). NOTE: Fuel pump may also be activated by connecting battery voltage to specified terminals on fuel pump. see scheme 7
8. If fuel pressure is within specification, go to next step. If fuel pressure exceeds specification, replace fuel pressure regulator mounted on fuel pump in the fuel tank. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. If fuel pressure is less than specified, check for leaking fuel hoses or connections, restricted fuel filter, defective fuel pump or defective fuel pressure regulator.
9. Remove scan tool from DLC No. 3. Start engine and note fuel pressure with engine idling. Fuel pressure should be 44-50 psi (3.1-3.5 kg/cm 2 ). Shut engine off and note fuel pressure. Fuel pressure should remain at least 21 psi (1.5 kg/cm 2 ) for a minimum of 5 minutes. If fuel pressure is within specification and holds as specified, go to next step. If fuel pressure is not within specification or does not hold as specified, check for defective fuel pump, fuel injector or fuel pressure regulator.
10. Release fuel pressure. Disconnect negative battery cable. Remove adapter, hose, fuel pressure gauge and fuel pipe connector.
11. Install No. 1 fuel pipe on fuel inlet pipe. Pull on No. 1 fuel pipe to ensure fuel pipe is properly locked on fuel inlet pipe. Reinstall fuel pipe clamp until "click" sound is heard. Pull upward on fuel pipe clamp to ensure fuel pipe clamp is securely locked on fuel inlet pipe. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump.

Scheme 18

Scheme 19

ES300, GS400, LS400, LX470, RX300 & SC400

1. Remove ignition coils. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. NOTE: Ignition coil may also be referred to as ignition coil/ignitor.
2. Reinstall electrical connectors on ignition coils. Remove spark plugs. Install spark plug on each ignition coil. Ground spark plugs against cylinder block. Disconnect electrical connectors at fuel injectors.
3. Crank engine and check for spark. If spark does not exist, check electrical connection at ignition coil. If electrical connection is okay, go to next step. If electrical connection is defective, repair as necessary and recheck for spark.
4. Install different ignition coil on spark plug and recheck for spark. If spark still does not exist, go to next step. If spark now exists with different ignition coil, replace original ignition coil.
5. Turn ignition on. Using voltmeter, check for battery voltage at ignition coil positive terminal. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch and ignition coil.
6. On all models, check resistance of camshaft position sensor(s). See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S05663331682000041300000) . If camshaft position sensor resistance is within specification, go to next step. If camshaft position sensor resistance is not within specification, replace camshaft position sensor. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.
7. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S31560514272000041300000) . If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.
8. Check ignition IGT signal from Engine Control Module (ECM) to ignition coil. If ignition IGT signal from ECM is defective, Diagnostic Trouble Code (DTC) P1300, P1305, P1310, P1315, P1320, P1325, P1330 or P1340 should set in ECM memory to indicate a specified ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs. DTCs P1330 or P1340 apply only to GS400, LS400, LX470 and SC400.
9. If ignition IGT signal is okay, substitute another ignition coil and recheck system operation. If ignition IGT signal is defective, check wiring between ECM and ignition coil. See «ECM LOCATION»(ref-2759-S05250097382000041300000) table. If wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation. Reinstall components. Install and tighten spark plugs to 13 ft. lbs. (18 N.m). ECM LOCATION Model (1) Location ES300 Behind Glove Box GS400 Driver's Side Front Corner Of Engine Compartment LS400, LX470 & RX300 Behind Glove Box SC400 Under Passenger's Side Front Carpet Below Instrument Panel (1) For illustration of ECM location, see THEORY & OPERATION article.

GS300 & SC300

1. Remove ignition coils. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Reconnect electrical connectors on ignition coils.
2. Remove spark plugs. Install spark plug on each ignition coil and spark plug wire. Ground spark plugs against cylinder block.
3. Crank engine and check for spark. If spark exists at spark plug on ignition coil, but not at spark plug on spark plug wire, go to next step. If spark does not exist at any spark plug, check ignition coil and ignitor electrical connections. Ignitor is located in engine compartment, on top of driver's side strut tower. If electrical connections are okay, go to step 5 . If electrical connections are defective, repair as necessary and recheck for spark.
4. Using ohmmeter, check resistance of spark plug wire. Replace spark plug wire if resistance exceeds 25,000 ohms per wire.
5. Turn ignition on. Using voltmeter, check for battery voltage at positive terminal on ignitor and ignition coil. See appropriate wiring diagram in WIRING DIAGRAMS article. If battery voltage exists, go to next step. If battery voltage does not exist, check wiring between ignition switch, ignition coil and ignitor. See appropriate wiring diagram in WIRING DIAGRAMS article.
6. Check ignition coil resistance. See «IGNITION COIL RESISTANCE»(ref-2759-S07034074892000041300000) . If ignition coil resistance is within specification, go to next step. If ignition coil resistance is not within specification, replace ignition coil.
7. Check resistance of camshaft position sensor. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S05663331682000041300000) . If camshaft position sensor resistance is within specification, go to next step. If camshaft position sensor resistance is not within specification, replace camshaft position sensor. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article.
8. Check resistance of crankshaft position sensor. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S31560514272000041300000) . If crankshaft position sensor resistance is within specification, go to next step. If crankshaft position sensor resistance is not within specification, replace crankshaft position sensor. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.
9. Check ignition IGT signal from Engine Control Module (ECM) to ignitor. If ignition IGT signal from ECM is defective, Diagnostic Trouble Code (DTC) P1300 should set in the ECM memory to indicate an ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article for retrieving of DTCs.
10. If ignition IGT signal is okay, substitute another ignitor and recheck system operation. If ignition IGT signal is defective, check wiring between ECM and ignitor. On GS300, ECM is located at driver's side front corner of engine compartment. On SC300, ECM is located under passenger's side front carpet below instrument panel. On all models, if wiring is defective, repair wiring as necessary and recheck system operation. If wiring is okay, substitute another ECM and recheck system operation. Reinstall components. Install and tighten spark plugs to 13 ft. lbs. (18 N.m).

CAMSHAFT POSITION SENSOR RESISTANCE

1. Disconnect electrical connector at camshaft position sensor. See «CAMSHAFT POSITION SENSOR LOCATION»(ref-2759-S27830566772000041300000) table. (Scheme 20)- (Scheme 22). CAMSHAFT POSITION SENSOR LOCATION Application Ohms ES300 & RX300 (1) Two Sensors Are Used, One At Each Flywheel End Of Cylinder Head, Just Below Valve Cover GS300 & SC300 Just Above Intake Manifold At Rear Corner Of Cylinder Head GS400, LS400, LX470 & SC400 Behind Driver's Side Upper Timing Belt Cover, Near Camshaft Sprocket With Electrical Connector Near Front Of Upper Timing Belt Cover (1) Camshaft position sensors may also be referred to as Variable Valve Timing (VVT) sensors.
2. Using ohmmeter, check resistance between electrical terminals on camshaft position sensor. (Scheme 20)- (Scheme 22). Ensure camshaft position sensor resistance is within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S26073248312000041300000) table. Replace camshaft position sensor if resistance is not within specification. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.

CAMSHAFT POSITION SENSOR RESISTANCE

Scheme 20

Scheme 21

Scheme 22

Scheme 23

Scheme 24

1. Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. (Scheme 23)and (Scheme 24).
2. Manufacturer lists inspection procedure with crankshaft position sensor removed before checking the resistance. On ES300 and RX300, remove passenger's side fender apron for access to crankshaft position sensor. On GS400 and LX470, remove lower engine cover for access to crankshaft position sensor.
3. On all models, disconnect electrical connector at crankshaft position sensor. Remove bolt and crankshaft position sensor. Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor. Replace crankshaft position sensor if resistance is not within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S08851177812000041300000) table.
4. Reinstall crankshaft position sensor. On ES300 and RX300, install and tighten crankshaft position sensor bolt to 71 INCH lbs. (8.0 N.m). On GS400 and LX470, install and tighten crankshaft position sensor bolt to 58 INCH lbs. (6.6 N.m). On all models, reinstall electrical connector on crankshaft position sensor.

Scheme 25

1. Crankshaft position sensor is located near crankshaft pulley, just above oil pan on passenger's side of engine with electrical connector located near water pump. Disconnect crankshaft position sensor electrical connector. (Scheme 25) Remove bolt from electrical connector retaining bracket. (Scheme 25)
2. Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor electrical connector. Ensure crankshaft position sensor resistance is within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S08851177812000041300000) table. Replace crankshaft position sensor if resistance is not within specification. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Reinstall electrical connector.

LS400 & SC400

1. On LS400, remove lower engine cover and oil pan protector for access to crankshaft position sensor. On SC400, remove lower engine cover for access to crankshaft position sensor. On all models, crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. (Scheme 24) Disconnect electrical connector at crankshaft position sensor.
2. Using ohmmeter, check resistance between electrical terminals on crankshaft position sensor. Ensure crankshaft position sensor resistance is within specification. See «CRANKSHAFT POSITION SENSOR RESISTANCE»(ref-2759-S08851177812000041300000) table. Replace crankshaft position sensor if resistance is not within specification. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Reinstall electrical connector.

CRANKSHAFT POSITION SENSOR RESISTANCE

Ignition coil resistance is not available from manufacturer.

Scheme 26

Scheme 27

1. Remove ignition coil. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.
2. Using ohmmeter, check ignition coil primary resistance between positive (+) and negative (-) electrical terminals on ignition coil. (Scheme 26) Replace ignition coil if ignition coil primary resistance is not within specification. See «IGNITION COIL RESISTANCE (OHMS)»(ref-2759-S32936811042000041300000) table.
3. Using ohmmeter, check ignition coil secondary resistance between electrical terminal and spark plug terminal on ignition coil. (Scheme 27) Replace ignition coil if ignition coil secondary resistance is not within specification. See «IGNITION COIL RESISTANCE (OHMS)»(ref-2759-S32936811042000041300000) table. Reinstall ignition coil. IGNITION COIL RESISTANCE (OHMS) Application Primary Secondary GS300 & SC300 Cold (1).33-.52 8500-14,700 Hot (2).42-.61 10,800-17,200 (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (51-100°C).

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ON-VEHICLE ADJUSTMENTS article.

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate SELF-DIAGNOSTICS article. If no hard diagnostic trouble codes are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.