Starting System: Diagnosis Toyota MR2 W30

TROUBLE SHOOTING

Note. See STARTER - GENERAL TROUBLE SHOOTING article in GENERAL INFORMATION.

ON-VEHICLE TESTING

Note. Before testing, ensure battery is fully charged, battery cables and terminal ends are tight and clean, and engine grounds are secure.

CLUTCH START SWITCH TEST

On manual transmission models, vehicle will not crank unless clutch pedal is depressed. If vehicle will not crank while clutch pedal is depressed, test clutch start switch by testing continuity. With switch ON (pushed in) there should be continuity. when the switch is OFF (out), there should not be continuity. (Scheme 1)

Scheme 1

IGNITION SWITCH TEST

See appropriate STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

STARTER RELAY TEST

1. Remove starter relay box cover. (Scheme 2)
2. Remove starter relay located and in engine compartment junction block.
3. Using an ohmmeter, verify continuity between relay terminals No. 1 and 2. (Scheme 3) Continuity should not exist between terminals No. 3 and 5. If continuity is not as specified, replace relay.
4. Check relay operation by applying battery voltage through terminals No. 1 and 2. (Scheme 3) Continuity should now exist between terminals No. 3 and 5. If relay does not test as indicated, replace relay.
5. Install starter relay.
6. Install starter relay box cover.

Scheme 2

Scheme 3

BEARING TEST

While applying inward force, turn bearing by hand. If resistance is felt or the bearing sticks, replace bearing.

NO-LOAD TEST

1. Remove starter. See «STARTER»(ref-163463-S27845121062004063000000) under REMOVAL & INSTALLATION.
2. Connect ammeter in series between starter motor terminal No. 30 (battery terminal) and a fully charged 12-volt battery. Connect battery negative lead to starter case ground. (Scheme 4)
3. Connect jumper wire to terminals No. 30 and 50 to engage starter. Starter drive pinion gear should extend quickly and spin smoothly. Verify starter amperage draw is within specifications of 90 amps or less at 11.5 volts.

Scheme 4

ARMATURE COIL TEST

1. Check for continuity between segments of commutator. (Scheme 5) If continuity is not present between any segment, replace armature.
2. Using ohmmeter, check for continuity between armature coil core and commutator. (Scheme 6) If continuity is present, replace armature.

Scheme 5

Scheme 6

BRUSHES & SPRINGS TEST

1. Use vernier calipers to check brush length. (Scheme 7) If length is less than specification, replace brush holder and field frame. See «STARTER SPECIFICATIONS»(ref-163463-S21486600572004063000000). If brushes are okay, go to step 2.
2. Check brush spring load using a spring scale. (Scheme 8) Pull the scale and take reading when spring separates from the brush. If the spring load is less that specification, replace the springs. See «STARTER SPECIFICATIONS»(ref-163463-S21486600572004063000000).
3. Using an ohmmeter, check that there is no continuity between the positive and negative brush holders. (Scheme 7)

Scheme 7

Scheme 8

CLUTCH ASSEMBLY & GEARS TEST

1. Inspect teeth on pinion gear, idler gear and clutch assembly for wear or damage. If damaged, replace gear or clutch assembly and inspect flywheel ring gear for wear or damage.
2. Inspect clutch pinion gear by rotating pinion gear counterclockwise. Ensure gear turns freely in counterclockwise direction, but locks up when turned clockwise. (Scheme 9) If not as specified, replace clutch assembly.

Scheme 9

COMMUTATOR TEST

1. If commutator surface is dirty or burnt, it can be cleaned with No. 400 grit sandpaper or on a lathe.
2. Place the commutator on V-blocks and use a dial indicator to measure runout (out-of-round). (Scheme 10) If commutator runout is more than specification, turn commutator on a lathe and proceed to step 3. For specification, see «STARTER SPECIFICATIONS»(ref-163463-S21486600572004063000000).
3. Measure Commutator diameter. (Scheme 11) See «STARTER SPECIFICATIONS»(ref-163463-S21486600572004063000000) If commutator diameter is less than minimum specification, replace armature.
4. Ensure undercut depth between commutator segments are clean, free of debris, and that edges are smooth, and within specification (Scheme 12) If undercut depth is less than minimum, use a hacksaw blade to correct it. See «STARTER SPECIFICATIONS»(ref-163463-S21486600572004063000000).

Scheme 10

Scheme 11

Scheme 12

FIELD FRAME (FIELD COIL) TEST

1. Using an ohmmeter, verify that there is continuity between the lead wire and field coil brush lead. If there is no continuity, replace the field frame. (Scheme 13)
2. Using an ohmmeter, verify that there is no continuity between the field coil end and field frame. If continuity is present, replace the field frame. (Scheme 13)

Scheme 13

MAGNETIC SWITCH TEST

1. Using an ohmmeter, check that there is continuity between terminals 50 and C. (Scheme 14) If there is no continuity, replace the repair service starter kit.
2. Using an ohmmeter, check. that there is continuity between terminal 50 and the switch body. (Scheme 14) If there is no continuity; replace the repair service starter kit.

Scheme 14