Interlock System - Shift Lock System Circuit Troubleshooting
Troubleshooting1. Press the brake pedal.
Are the brake lights ON?
YES - Go to step 2.
NO - Repair faulty brake light circuit.
2. Turn the ignition switch ON (II), and shift to the P position.
3. Press the brake pedal, and release the accelerator pedal.
4. Measure the voltage between PCM connector terminal A28 and body ground.
Is there battery voltage?
YES - Check for an open in the wire between PCM connector terminal A28 and the multiplex control unit (driver's). If the wire is OK, check for loose terminal fit in the multiplex control unit (driver's) connectors. If necessary, substitute a known-good multiplex control unit (driver's) and recheck.
NO - Go to step 5.
5. Turn the ignition switch OFF, and disconnect the battery negative terminal.
6. Disconnect PCM connectors A (32P) and B (25P).
7. Reconnect the battery negative terminal.
8. Press the brake pedal, and measure the voltage between PCM connector terminals A32 and B20 or B22.
Is there battery voltage?
YES - Release the brake pedal, and go to step 9.
NO - Repair open in the wire between PCM connector terminal A32 and the brake pedal position switch.
9. Disconnect the battery negative terminal.
10. Connect PCM connectors A (32P) and B (25P).
11. Reconnect the battery negative terminal.
12. Turn the ignition switch ON (II).
13. Measure the voltage between PCM connector terminals C27 and B20 or B22.
Is there about 0.5 V (throttle fully closed)?
YES - Go to step 18.
NO - Go to step 14.
14. Turn the ignition switch OFF.
15. Disconnect the Throttle Position Sensor (TPS) connector.
16. Turn the ignition switch ON (II).
17. Measure the voltage between TPS connector terminals No. 1 and No. 3.
Is there about 5 V?
YES - Check for a short or an open in the wire between PCM connector terminal A27 and the TPS. If the wire is OK, replace the TPS.
NO - Go to step 18.
18. Turn the ignition switch OFF, and disconnect the battery negative terminal.
19. Disconnect PCM connector C (31P).
20. Reconnect the battery negative terminal.
21. Check for continuity between TPS connector terminal No. 1 and body ground, and between terminal No. 3 and body ground.
Is there continuity?
YES - Check for a short to ground in the wires between TPS connector terminals No. 1 and No. 3, and the PCM. If the wires are OK, replace the PCM.
NO - Go to step 22.
22. Disconnect the shift lock solenoid connector.
23. Check for continuity between the No. 2 terminal of the shift lock solenoid connector and multiplex control unit (driver's) connector terminal B22.
Is there continuity?
YES - Go to step 24.
NO - Repair open in the wire between multiplex control unit (driver's) connector terminal B22 and the shift lock solenoid.
24. Turn the ignition switch ON (II).
25. Measure the voltage between No. 1 terminal of the shift lock solenoid connector and body ground.
Is there battery voltage?
YES - Go to step 26.
NO - Check for blown No. 9 (10A) fuse in the driver's under-dash fuse/relay box. If the fuse is OK, repair open or short in the wire between the No. 1 terminal of the shift lock solenoid connector and the driver's under-dash fuse/relay box.
26. Connect the battery positive terminal to the No. 1 terminal of the shift lock solenoid connector, and connect the battery negative terminal to the No. 2 terminal.
NOTE: Do not connect the No. 2 terminal to the battery positive terminal or you will damage the diode inside the shift lock solenoid.
27. Check the shift lock solenoid operates.
Does the shift lock solenoid operate properly?
YES - Check for a loose multiplex control unit (driver's) connector. If necessary, substitute a known-good multiplex control unit (driver's) and recheck.
NO - Replace the shift lock solenoid.