Starter: Diagnosis Lexus LS II

CLUTCH START SWITCH TEST

Disconnect electrical connector from clutch start switch located above clutch pedal. Continuity should exist between terminals with switch button pushed in. No continuity should exist with switch button released. If continuity is not as specified, replace switch.

PARK/NEUTRAL POSITION (PNP) SWITCH TEST

Disconnect park/neutral position switch connector. See ELECTRICAL COMPONENT LOCATIONS under DESCRIPTION & OPERATION. Check for continuity between specified terminals of park/neutral position switch. See PARK/NEUTRAL POSITION (PNP) SWITCH CONTINUITY SPECIFICATIONS table. (Scheme 2) If continuity is not as specified, replace park/neutral position switch.

PARK/NEUTRAL POSITION (PNP) SWITCH CONTINUITY SPECIFICATIONS

Scheme 2

Remove starter relay. See ELECTRICAL COMPONENT LOCATIONS under DESCRIPTION & OPERATION. Starter relay is okay if it tests as follows

1. There is continuity between terminals No. 1 and 2. (Scheme 3)
2. There is no continuity between terminals No. 3 and 5.
3. There is continuity between terminals No. 3 and 5 when battery voltage is applied across terminals No. 1 and 2.

Scheme 3

CIRCUIT TEST

1. Under left side of instrument panel, remove trim panel, key cylinder pad and duct, as necessary, to access junction block. Remove set bolts and clamp securing junction block. Separate tilt/telescopic ECU from junction block.
2. Remove wiring harness clamp. Lower junction block. Disconnect 12-pin connector from body control ECU, located above junction block. Place shift lever in Neutral (or depress clutch pedal). While holding ignition switch in START position, measure voltage between body ground and terminal No. 2 of body control ECU. (Scheme 4)
3. If 10-14 volts is measured, replace body control ECU. If 10-14 volts is not measured, check for faulty starter relay, park/neutral position switch (clutch switch on M/T), or wiring harness.

Scheme 4

BENCH TESTING

SOLENOID TEST

1. Disconnect starter field coil lead from terminal "C". Connect battery to starter solenoid. Refer to step No. 1 in illustration. (Scheme 5) Clutch pinion gear should move outward. If clutch pinion gear does not move outward, replace starter solenoid.
2. If gear moves outward, disconnect jumper lead from terminal "C". Refer to step No. 2 in illustration. (Scheme 5) Clutch pinion gear should remain in outward position. If clutch pinion gear DOES NOT remain in outward position, replace starter solenoid.
3. If clutch pinion gear remains in outward position, disconnect jumper lead from starter housing. Refer to step No. 3 in illustration. (Scheme 5) Clutch pinion gear should move inward. If clutch pinion gear does not move inward, replace starter solenoid.

Scheme 5

NO-LOAD TEST

Connect battery and ammeter to starter. Refer to step No. 4 in illustration. (Scheme 5) Starter armature should rotate smoothly and steadily. Amperage draw should be within specification. See NO-LOAD TEST SPECIFICATIONS table.

NO-LOAD TEST SPECIFICATIONS

ARMATURE TEST

1. Ensure continuity exists between all segments of commutator. Ensure continuity does not exist between commutator and armature coil core. If continuity is not as specified, replace armature. If commutator diameter does not meet minimum specification, replace armature. See «STARTER OVERHAUL SPECIFICATIONS»(ref-34350-S36570844862001011800000) table under OVERHAUL.
2. If commutator runout exceeds maximum specification, turn commutator on a lathe. If depth of mica undercut does not meet minimum specification, use a hacksaw blade to remove mica from between segments.

FIELD WINDINGS TEST

Ensure continuity exists between starter solenoid lead and brush lead. Ensure continuity does not exist between brush lead and stator housing. If continuity is not as specified, replace field windings.

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING - BASIC PROCEDURES article.

Note. Starter is located under lower intake manifold, at rear of engine.