No Crank No Start on 1987 Auto Turbo - Neutral Safety Switch Bypass

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Problem

1987 automatic turbo MK3 Supra will not start. Key turns but engine gives no response - no cranking. Dash lights flicker when key is turned but nothing else happens. Battery is charged, fuses checked, starting in neutral makes no difference.

Key turns but engine does not crankNo starter click or engagementDash lights flicker/dim when key is turnedNo difference starting in Park vs NeutralBattery is charged and fuses are good

Root Cause

Failed Neutral Safety Switch (NSS), also called the neutral start switch. On automatic MK3 Supras, this switch on the driver's side of the transmission tells the ECU the car is in Park or Neutral before allowing the starter to engage. When the switch fails, the starter circuit is never completed, resulting in no crank.

Confidence

Moderate confidence — Multiple community members agreed on this solution

View Original Thread →Posted October 2024 on SupraForums.com