DTC P1512: VARIABLE TUMBLE CONTROL SYSTEM (VTCS), STUCK CLOSED Condition DTC is set when PCM detects air flow is more than 30 gram/sec. When engine speed is more than 3000, engine coolant temperature is more than 176 °F (80 °C), and throttle valve opening angle is more than 75 percent. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are: Possible causes are: à   ECT sensor malfunction. à   MAF sensor malfunction. à   IAT sensor malfunction. à   EGR boost sensor malfunction. à   TP sensor malfunction. à   CKP sensor malfunction. à   VTCS solenoid valve malfunction. à   VTCS shutter valve stuck closed. à   VTCS shutter valve actuator stuck closed. à   Short circuit between PCM and VCTS solenoid valve. à   PCM malfunction. Diagnosis & Repair Procedure 1. Ensure FREEZE FRAME DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step. 2. Using scan tool, clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Ensure engine coolant temperature is 68 °F (20 °). Drive vehicle with engine speed at more than 3000 RPM and mass air flow at less than 30 gram/sec. Check for DTCs. If DTC P1512 is present, go to next step. If DTC P1512 is not present, problem is intermittent. See TROUBLE SHOOTING - NO CODES article. 3. Check for any other DTCs. If any other DTC is present, repair that DTC first. If no other DTCs are present, go to next step. 4. Check VTCS shutter valve actuator operation. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If VTCS shutter valve actuator is okay, go to next step. If VTCS shutter valve actuator is faulty, replace as necessary and go to step 7. 5. Check VTCS solenoid valve operation. See SYSTEM & COMPONENT TESTING - MIATA, MILLENIA, MPV, PROTEGE & 626 article. If VTCS solenoid valve is okay, go to next step. If VTCS solenoid valve is faulty, replace as necessary and go to step 7. 6. Turn ignition off. Disconnect appropriate PCM connector. Check connector for loose or damaged terminals, poor contact or corrosion. Repair as necessary and go to next step. If no problem is found, go to next step. 7. Reconnect all connectors. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. Start engine. Using scan tool, ensure ECT PID is less than 68 °F (20 °C), RPM PID is less than 3000 RPM and MAF PID is less than 30 gram/sec. Check forDTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If DTC P1512 is present, replace PCM and go to next step. If DTC P1512 is not present, go to next step. 8. Cycle ignition from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
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Sunday, February 22nd, 2009 AT 8:15 AM
