Z. Automatic Transmission Interlock System

Honda automatic transmissions are equipped with the following devices to prevent inadvertent shifting:
. Automatic transmission selector with shift lock.
. Key cylinder with interlocked ignition key.

Shift Lock System:

The shift lock system prevents the shift lever from moving to Reverse or D4 from the Park position, unless the brake pedal is depressed and the accelerator is in its rest position.

Note:
. The shift lever cannot be shifted when the brake pedal and the accelerator are stepped on at the same time.
. In case of system malfunction, the shift lever can be released by pushing a key into the release slot near the shift lever.

Key Interlock System:

The ignition key cannot be removed from the ignition switch, unless the shift lever is in Park. When the shift lever is in any position other than Park, a solenoid is activated, making it impossible for the key to be removed, until the shift lever is moved to Park.

Troubleshooting:

If you are experiencing problems, particularly in cold weather, check for a faulty automatic transmission gear position switch (most likely). Next, check for a possible faulty steering lock assembly (key interlock solenoid and key interlock switch). See section K.

Automatic Transmission Gear Position Switch Replacement

1. Remove console and disconnect 14-P connector from switch.
2. Remove both console switch mounting nuts.
3. Position switch slider to "Neutral."
4. Move shift lever to "Neutral," then slip switch into position.
5. Attach switch with both nuts.
6. Test switch in Park and Neutral positions of shift lever. Engine should start, when shift lever is in Neutral (anywhere in the range of free play).
7. Connect 14-P connector, clamp harness, and install console.

Also, take a test light or multimeter and check all under-hood and under-dash fuses. These fuses can affect power going to the 8-P connector and the interlock control unit. Check for good contact between the connector and socket terminals. If the problem remains, you may want to replace the interlock control unit, which is located near the left kick panel (close to the main relay). These are sophisticated systems that can sometimes challenge the best technicians.