Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMAZDA2005MX-5 MIATA L4-1.8L DOHCREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTECHNICAL SERVICE BULLETINSCUSTOMER INTERESTENGINE CONTROLS - MIL ON/DTC P2004 ON START UP
2005 Mazda MX-5 Miata L4-1.8L DOHC
Engine Controls - MIL ON/DTC P2004 On Start Up
2005 Mazda MX-5 Miata L4-1.8L DOHCSECTION Engine Controls - MIL ON/DTC P2004 On Start Up
TSB: 01-055/06
2004-2005 MIATA, 2004-2005 MAZDASPEED MX-5 - MIL ON / P2004 SETS AFTER STARTING ENGINE
APPLICABLE MODEL(S)/VINS
2004-2005 Miata
2004-2005 MAZDASPEED MX-5
DESCRIPTION
On some vehicles, after sitting overnight and started, the MIL comes on and DTC P2004 sets into PCM memory. This occurs because vacuum (momentarily) does not flow into the Variable Tumble Control System (VTCS) shutter valve actuator. The contact surface between the valve and the valve body inside the check valve is smooth causing the valve to momentarily stick before more vacuum applies, opening the valve.
As a mass-production change, the contact surface between the valve and valve body has been made rougher to prevent sticking condition. Customers having this concern should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
1. Verify customer concern.
2. Replace check valve with a modified part.
NOTE:
^ Modified check valve can be identified by Yellow marking on the valve body.
3. Verify repair.
PART(S) INFORMATION
WARRANTY INFORMATION
NOTE:
^ This warranty information applies only to verified customer complaints on vehicles eligible for warranty repair. Refer to the Warranty Wizard for warranty term information.
^ Additional diagnostic time cannot be claimed for this repair.
Disclaimer
2004-2005 MIATA, 2004-2005 MAZDASPEED MX-5 - MIL ON / P2004 SETS AFTER STARTING ENGINE
APPLICABLE MODEL(S)/VINS
2004-2005 Miata
2004-2005 MAZDASPEED MX-5
DESCRIPTION
On some vehicles, after sitting overnight and started, the MIL comes on and DTC P2004 sets into PCM memory. This occurs because vacuum (momentarily) does not flow into the Variable Tumble Control System (VTCS) shutter valve actuator. The contact surface between the valve and the valve body inside the check valve is smooth causing the valve to momentarily stick before more vacuum applies, opening the valve.
As a mass-production change, the contact surface between the valve and valve body has been made rougher to prevent sticking condition. Customers having this concern should have their vehicle repaired using the following repair procedure.
REPAIR PROCEDURE
1. Verify customer concern.
2. Replace check valve with a modified part.
NOTE:
^ Modified check valve can be identified by Yellow marking on the valve body.
3. Verify repair.
PART(S) INFORMATION
WARRANTY INFORMATION
NOTE:
^ This warranty information applies only to verified customer complaints on vehicles eligible for warranty repair. Refer to the Warranty Wizard for warranty term information.
^ Additional diagnostic time cannot be claimed for this repair.
Disclaimer
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.