Shift Interlock System: Operation
The Brake Transmission Shifter/Ignition Interlock (BTSI) is engaged whenever the ignition switch is in the LOCK or ACC position (Fig 1). An additional electrically activated feature will prevent shifting out of the PARK position unless the brake pedal is depressed at least one-half inch. A magnetic holding device integral to the interlock cable is energized when the ignition is in the ON position. When the key is in the ON position and the brake pedal is depressed, the shifter is unlocked and will move into any position. The interlock system also prevents the ignition switch from being turned to the LOCK or ACC position, unless the shifter is in the gated PARK position.
The following chart describes the normal operation of the Brake Transmission Shift Interlock (BTSI) system. If the "expected response" differs from the vehicle's response, then system repair and/or adjustment is necessary.
| ACTION | EXPECTED RESPONSE |
|---|---|
| 1. Turn key to the "ACC" position and depress brake pedal. | 1. Shifter CAN be shifted out of park. |
| 2. Turn key to the "ON" position, with foot off of brake pedal. | 2. Shifter CANNOT be shifted out of park. |
| 3. Turn key to the "ON" position and depress the brake pedal. | 3. Shifter CAN be shifted out of park. |
| 4. Leave shifter in any gear and try to return key to the "LOCK" position. | 4. Key cannot be returned to the "LOCK" position. |
| 5. Return shifter to "PARK" and try to remove the key. | 5. Key can be removed (after returning to "LOCK" position). |
| 6. With the key removed, try to shift out of "PARK". | 6. Shifter cannot be shifted out of "PARK". |
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NOTE:
Any failure to meet these expected responses requires system adjustment or repair.
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