Variable Tumble Control System (VTCS) Check

1. Connect NGS scan tool to DLC-2. Select ECT PID. Ensure ECT is 149°F (65°C) or less. Start engine. VTCS shutter valve actuator rod should be pulled. If rod is pulled, go to next step. If rod is not pulled, inspect following:
   • VTCS shutter valve actuator
   • VTCS delay valve
   • VTCS chamber
   • VTCS control solenoid valve
   • Vacuum hoses
   • Wiring harness and connectors between PCM, VTCS solenoid valve and main relay.

   Repair or replace wiring harness or components as necessary. See WIRING DIAGRAMS article.

2. Select RPM PID. Inspect VTCS shutter valve actuator rod operation. See VTCS SHUTTER VALVE ROD OPERATION (MIATA 1.8L & PROTEGE, PROTEGE5 & 626 2.0L)  table. If rod operation is not as specified, check following:
   • VTCS shutter valve actuator
   • VTCS delay valve
   • VTCS chamber
   • VTCS control solenoid valve
   • Vacuum hoses
   • Wire harness and connectors between PCM terminal No. 73, VTCS solenoid valve and main relay.
   VTCS SHUTTER VALVE ROD OPERATION (MIATA 1.8L & PROTEGE, PROTEGE5 & 626 2.0L)
   
   

   Application - Engine RPM		VTCS Shutter Valve Actuator
   Miata 1.8L
   Less Than 3500		Operate
   More Than 3500		Does Not Operate
   Protege & Protege5 2.0L
   Less Than 3000		Operate
   More Than 3000		Does Not Operate
   626 2.0L
   Less Than 3250		Operate
   More Than 3250		Does Not Operate

For system testing, see appropriate SELF-DIAGNOSTICS article.