No Crank / No Start - Theft Deterrent System Starter Kill Bypass
Electricalbeginner✓ OP Confirmed
Problem
Automatic transmission MK3 Supra would not crank at all when turning the key. No clicking sound from the starter relay or starter solenoid. The theft deterrent system's internal relay had failed, permanently activating the starter kill function and preventing the starter circuit from completing.
Engine does not crank at all when key is turned to startNo clicking sound from passenger side kick panel area when attempting to startNo clicking sound from starter solenoid in engine baySecurity indicator light not blinking or solidAlarm engages every time car sits for a few hoursUnlocking passenger door with key does not deactivate starter kill
Root Cause
The theft deterrent ECU's internal relay (which grounds pin 13, the blue/orange wire, to energize the starter relay coil) had failed in the open position. This prevented the starter relay in the passenger side kick panel from closing, breaking the starter circuit and disabling cranking even though the alarm indicator appeared inactive.
Confidence
High confidence — Original poster confirmed this resolved the issue
View Original Thread →Posted September 2023 on SupraForums.com