TSRM/MK4 Supra/Repair Manual
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p.046

PS/Steering — Electronic Control System Troubleshooting Flow–chart, page 47

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p.048
Electronic Control System Troubleshooting Flow–chart — MK4 Supra Steering, page 47
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Page text (OCR transcript)
ELECTRONIC CONTROL SYSTEM
TROUBLESHOOTING FLOW–CHART

Trouble Symptom
• Hard steering at idle or low–speed driving.
• Steering too sensitive during high–speed driving.

Preliminary Check
• Check tire pressure.
• Check lubrication of suspension and steering linkage.
• Check front wheel alignment.
• Check steering system joint and suspension arm ball joint.
• Check for bent steering column.
• Check that all connectors are secure.
• Check PS pump fluid pressure. (See page SR–37)

Turn ignition switch on.

Is ECU–IG fuse normal?
No → Replace fuse.
Is operation normal?
No → Short circuit in wire harness between fuse and ECU terminal +B.
Yes → Fuse faulty.
Yes ↓

Disconnect the ECU connector.

Check 1.
Check that there is battery voltage (10 — 14V) between the ECU terminal +B and body ground.

R07582

Yes
No
↓
Open circuit in wire harness between the fuse and ECU terminal +B.

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