Applicable models: 2004-’05 Miata and MazdaSpeed MX-5.

On some vehicles, after sitting overnight and being 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 the sticking condition. Customers having this concern should have their vehicle ­repaired using the following repair procedure.

Repair Procedure:

1. Verify the customer’s concern.

2. Replace the check valve with a modified part (P/N BPYJ-13-995).
Note: The modified check valve can be identified by the yellow marking on the valve body. See Fig. 1.

3. Verify the repair.

Courtesy of ALLDATA.