For 1990-2009 cars only
| • | Prior to making any checks or adjustments to the modulator, check the following conditions: |
| - | Check the engine performance. Refer to the engine manufacturer service manual. |
| - | Check the adjustment of the accelerator linkage. Refer to Engine Mechanical for diesel engines only. |
| • | Diesel engines use a mechanically operated modulator valve in order to aid in transmission shifts. Adjust the modulator cables as needed. Refer to Transmission Modulator Cable Adjustment . |
| • | Gasoline engines use a vacuum modulator valve in order to aid transmission shifts. Check the vacuum modulator for proper operation. Refer to Vacuum Modulator Inspection . |
