Key Interlock System Circuit Troubleshooting

Disconnect the key switch connector (7P) from the steering lock assembly.
Connect the No. 7 terminal of the key switch connector to the battery positive terminal, and connect the No. 5 terminal to the battery negative terminal.

Fig 1: Connecting Battery To Key Switch Connector (7P)
Turn the ignition switch to ACC (I) then push the ignition key.
Check the key interlock solenoid operation. A clicking sound should be heard while pushing the ignition key, and you should not be able to turn it to the OFF position.
Does the key interlock solenoid operate properly?

YES - Go to step 5.

NO - Faulty key interlock solenoid/switch. Replace the ignition key cylinder/steering lock assembly.
Measure the voltage between the No. 7 terminal and body ground.

Fig 2: Measuring Voltage Between No. 7 Terminal & Body Ground

Is there battery voltage?

YES - Go to step 6.

NO - Check for a blown No. 47 (20A) fuse in the under-hood fuse/relay box. If the fuse is OK, repair open or short in the wire between the No. 7 terminal of the key switch connector and under hood fuse/relay box.
Disconnect the park pin switch connector on the shift lever.
With the shift lever in Park and pulled back toward the driver, check for continuity between the No. 1 and No. 3 terminals of the park pin switch connector.

Fig 3: Checking For Continuity Between No. 1 & No. 3 Terminals Of Park Pin Switch Connector

Is there continuity?

YES - Go to step 8.

NO - Repair open in the wires between the park pin switch and the connector. If the wires are OK replace the park pin switch.
Check for continuity between the No. 3 terminal of the park pin switch connector and the No. 5 terminal of the key switch connector.

Fig 4: Checking For Continuity Between No. 3 Terminal Of The Park Pin Switch Connector & No. 5 Terminal Of The Key Switch Connector

Is there continuity?

YES - Go to step 9.

NO - Repair open in the wire between No. 3 terminal of the park pin switch connector and the No. 5 terminal of the key switch connector.
Check for continuity between the No. 1 terminal of the park pin switch connector and body ground.

Fig 5: Check For Continuity Between No. 1 Terminal Of Park Pin Switch Connector & Body Ground

Is there continuity?

YES - Check for a loose key switch connector and park pin switch connector. If necessary, substitute a known-good steering lock assembly.

NO - Repair open in the wire between the No. 1 terminal of the park pin switch connector and ground (G401), or repair poor ground (G401).