Engine Controls - Basic Diagnostic Procedures: Other Lexus LS III

Compression

Warm engine to normal operating temperature before checking 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-11539-S32302951312000111700000). Disconnect negative battery cable.
2. Remove cover located on top of engine to gain access to front fuel pipe at front of driver's side fuel rail. (Scheme 11)
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 12) 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 4
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. Start engine. Note fuel pressure with engine idling. Fuel pressure should be 38-44 psi (2.7-3.1 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.
9. 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.
10. 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).
11. Install negative battery cable. Check for fuel leaks by using scan tool to energize fuel pump. Install engine cover.

Scheme 11

Scheme 12

Scheme 13

1. Ensure battery is fully charged. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-11539-S32302951312000111700000). Disconnect negative battery cable.
2. Purchase a No. 1 fuel pipe Part No. (23801-20120) from parts department. No. 1 fuel pipe fits between fuel rails and fuel inlet pipe. (Scheme 13) Remove fuel pipe connector from end of NEW No. 1 fuel pipe. see scheme 6
3. Remove fuel pipe clamp from No. 1 fuel pipe at fuel inlet pipe. (Scheme 13) 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 14)
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 15) 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 4
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 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 14

Scheme 15

ES300, GS430, LS430, LX470 & RX300

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 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-11539-S24712735912000111700000) . 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-11539-S11522632152000111700000) . 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 appropriate SELF-DIAGNOSTICS article for retrieving of DTCs. DTCs P1330 or P1340 apply only to GS430, LS430 and LX470.
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-11539-S38918314302000111700000) 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 GS430 & LS430 Driver's Side Front Corner Of Engine Compartment LX470 & RX300 Behind Glove Box (1) For illustration of ECM location, see THEORY & OPERATION article.

GS300 & IS300

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 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 WIRING DIAGRAMS article.
6. Check ignition coil resistance. See «IGNITION COIL RESISTANCE»(ref-11539-S39510185532000111700000) table. 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-11539-S24712735912000111700000) . 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-11539-S11522632152000111700000) . 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 ECM memory to indicate an ignitor circuit malfunction. See SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS 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. ECM is located at driver's side front corner of engine compartment. 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-11539-S10169391052000111700000) table. (Scheme 16)- (Scheme 18). CAMSHAFT POSITION SENSOR LOCATION Application Ohms ES300 & RX300 (1) Two Sensors Are Used, One At Rear Of Each Cylinder Head, Just Below Valve Cover GS300 & IS300 Just Above Intake Manifold At Rear Corner Of Cylinder Head GS430, LS430 & LX470 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 16)- (Scheme 18). Ensure camshaft position sensor resistance is within specification. See «CAMSHAFT POSITION SENSOR RESISTANCE»(ref-11539-S35896236832000111700000) table. Replace camshaft position sensor if resistance is not within specification. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article.

CAMSHAFT POSITION SENSOR RESISTANCE

Scheme 16

Scheme 17

Scheme 18

Scheme 19

Scheme 20

1. Crankshaft position sensor is located at front of crankshaft, near crankshaft pulley. (Scheme 19)and (Scheme 20).
2. Manufacturer lists inspection procedure with crankshaft position sensor removed before checking resistance. On ES300 and RX300, remove passenger's side fender apron for access to crankshaft position sensor. On GS430, LS430 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-11539-S42056416142000111700000) table. CRANKSHAFT POSITION SENSOR RESISTANCE Application Ohms All Models Cold (1) 1630-2740 Hot (2) 2065-3225 (1) Cold is with temperature of 14-122°F (-10-50°C). (2) Hot is with temperature of 122-212°F (50-100°C).
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 GS430 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 21

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 21) Remove bolt from electrical connector retaining bracket.
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-11539-S42056416142000111700000) table. Replace crankshaft position sensor if resistance is not within specification. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Reinstall electrical connector.

Ignition coil resistance is not available from manufacturer.

Scheme 22

Scheme 23

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 22) Replace ignition coil if ignition coil primary resistance is not within specification. See «IGNITION COIL RESISTANCE (OHMS)»(ref-11539-S41326481732000111700000) table.
3. Using ohmmeter, check ignition coil secondary resistance between electrical terminal and spark plug terminal on ignition coil. (Scheme 23) Replace ignition coil if ignition coil secondary resistance is not within specification. See «IGNITION COIL RESISTANCE (OHMS)»(ref-11539-S41326481732000111700000) table. Reinstall ignition coil. IGNITION COIL RESISTANCE (OHMS) Application Primary Secondary GS300 & IS300 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.