Starters: Diagnosis Isuzu Oasis I

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING article in GENERAL INFORMATION.

ON-VEHICLE TESTING

Note. On models with radio anti-theft protection system, obtain radio security code from vehicle owner, before disconnecting battery cable.

STARTER TEST

Note. Test starter at an ambient temperature of 59-100°F (15-38°C) as readings may vary in different temperature conditions.

1. Remove PGM-FI fuse, to disable ignition system. PGM-FI (15-amp) fuse is located in underhood fuse/relay block. Connect a voltmeter and an ammeter to battery. (Scheme 2)
2. Place shift lever in Park or Neutral position and crank engine. If cranking voltage does not drop below 8.5 volts, and current draw does not exceed 350 amps, starter is okay. If starter does not crank engine, go to next step. If starter cranks erratically or too slowly, go to step 6.
3. Load test battery. Check battery cable terminal ends for poor, loose, or corroded connections. Check gear position switch or starter relay for poor, loose, or corroded electrical connections. Repair or replace as necessary. If all connections are okay, turn ignition switch to START position. If starter cranks engine, system is okay. If starter does not crank engine, go to next step.
4. Remove Black/White wire connector from terminal "S" of starter solenoid. (Scheme 6) Connect a remote starter switch between positive battery terminal and terminal "S" of starter solenoid. Depress remote starter switch. If starter does not crank engine, remove starter and diagnose internal problem, or replace starter. See «BENCH TESTING»(ref-4246-S16207503482000061600000). If starter cranks engine, check starting system components. See «GEAR POSITION SWITCH TEST»(ref-4246-S30781072202000061600000), «IGNITION SWITCH TEST»(ref-4246-S42492710712000061600000) and «STARTER RELAY TEST»(ref-4246-S07154061512000061600000). If components are okay, go to next step.
5. Check Black/White wire between starter relay and ignition switch, and White/Red wire between starter and starter relay for open circuit.
6. Remove starter. Inspect starter drive gear for damaged teeth. Inspect ring gear for damaged teeth. If teeth are not damaged, bench test starter. See «BENCH TESTING»(ref-4246-S16207503482000061600000). If either ring gear or drive gear have damaged teeth, replace as necessary.

Scheme 2

GEAR POSITION SWITCH TEST

1. Disconnect gear position switch connector, located above transaxle, near gear position switch. (Scheme 3)
2. Using a DVOM, check continuity between specified terminals of gear position switch. See «GEAR POSITION SWITCH CONTINUITY»(ref-4246-S31462510632000061600000) table. Replace gear position switch if continuity is not as specified.

GEAR POSITION SWITCH CONTINUITY

Scheme 3

STARTER RELAY TEST

1. Locate and remove starter relay from vehicle. Connect power and ground to relay terminals No. 2 and 4. (Scheme 4) Ensure continuity exists between relay terminals No. 1 and 2.
2. Disconnect power and ground from terminals No. 2 and 4. Continuity should no longer exist between terminals No. 1 and 3. Replace starter relay if it does not test as specified.

Scheme 4

IGNITION SWITCH TEST

1. Remove lower instrument panel cover and driver-side knee bolster. Disconnect 7-pin connector from underdash fuse/relay box. (Scheme 5)
2. Using DVOM, check continuity between specified connector terminals, with ignition switch in appropriate position. If continuity is not as specified, replace ignition switch.

Scheme 5

Pull-In Test

Check continuity between starter solenoid terminals "S" and "M". (Scheme 6) If continuity exists, pull-in coil is okay. If continuity does not exist, replace starter solenoid.

Hold-In Test

Check continuity between terminal "S" and armature housing (ground). (Scheme 6) If continuity exists, hold-in coil is okay. If continuity does not exist, replace starter solenoid.

Scheme 6

ARMATURE TEST

1. Place armature in growler. Turn on growler, and hold hacksaw blade over armature. Slowly rotate armature. If armature attracts hacksaw blade or if hacksaw blade vibrates, armature is defective and must be replaced. If blade does not respond as described, go to next step.
2. Remove armature from growler. Check continuity between commutator and armature, and between commutator and shaft. Continuity should not exist. If continuity exists in either case, replace armature.
3. Check for continuity between each commutator segment. Continuity should exist. If an open circuit exists between any 2 segments, replace armature.
4. Inspect armature for wear or damage due to contact with field coil magnets. Clean commutator surface, and polish with No. 500-600 sandpaper if necessary. If surface is scored, out-of-round or pitted, turn commutator on a lathe.
5. If mica depth is not within specification, undercut with a hacksaw blade to minimum depth. See «STARTER SPECIFICATIONS»(ref-4246-S11280576982000061600000) .

BRUSH HOLDER TEST

1. Using a DVOM, check continuity between positive and negative brush holders (brackets). Continuity should not exist. If continuity exists, brush holder assembly is shorted and must be replaced.
2. Check brush length and spring tension. If brush length or spring tension is less than specification, replace brushes. See «STARTER SPECIFICATIONS»(ref-4246-S11280576982000061600000) . Ensure brushes move freely in holders.

OVERRUNNING CLUTCH TEST

Note. If starter drive gear teeth are damaged, check condition of flex plate ring gear.

1. Rotate overrunning clutch on shaft. (Scheme 7) If clutch does not lock when rotated in one direction and rotates smoothly in other direction, replace overrunning clutch assembly.
2. Inspect starter drive gear for wear or damage. If gear is damaged, replace overrunning clutch assembly. Drive gear is not available separately.

Scheme 7