Central Processing Unit (CPU)
Locate CPU unit behind left kick panel. Leave CPU connector attached. Using DVOM, measure voltage at specified terminals of CPU connector (backprobe connector). See Figure and Figure.
Also, refer to the CPU CONNECTOR PIN VOLTAGES & CONTINUITY . Disconnect CPU connector and check continuity at specified terminals. If voltage measurements or continuity are not as specified, check related components and wiring harnesses. If related components amd wiring harnesses are okay, but system is still not functioning properly, replace CPU.
CPU CONNECTOR PIN VOLTAGES & CONTINUITY
| Terminal |
Desired Condition |
| 16-Pin Connector |
| 1C (15-Amp ROOM Fuse), Constant |
Battery Voltage |
| 1D (CPU Ground), Constant |
Continuity |
| 1E (Door Switch) |
| All Doors Closed |
No Continuity |
| Any Door Open |
Continuity |
| 1I (Key Reminder Switch) |
| Key Inserted |
Battery Voltage |
| Key Removed |
No Voltage |
| 20-Pin Connector |
| 2A (Horn Relay) |
| Horn Off |
Battery Voltage |
| Horn On |
No Voltage |
| 2B (Headlight Relay) |
| Headlights Off |
Battery Voltage |
| Headlights On |
No Voltage |
| 2C (Starter Cut Relay), |
| Ignition On |
Battery Voltage |
| 2D (Security Light) * |
| Light Off |
Battery Voltage |
| Light On |
No Voltage |
| 2E (Door Lock Timer Unit) |
| .4 Sec. After Switch Unlocked |
No Voltage |
| Other |
Battery Voltage |
| 2F (Door Key Cylinder Switch) |
| Locked |
No Continuity |
| Unlocked |
Continuity |
| 2G (Door Lock Timer Unit) |
| .4 Sec. After Switch Locked |
No Voltage |
| Other |
Battery Voltage |
| 2H (Trunk Key Cylinder Switch) |
| Locked |
No Continuity |
| Unlocked |
Continuity |
| 2I (Door Lock Timer Unit) |
| .4 Sec. After UNLOCK Pressed |
No Voltage |
| Other |
Battery Voltage |
| 2J (Trunk Compartment Light Switch) |
| Trunk Lid Closed |
Battery Voltage |
| Trunk Lid Open |
No Voltage |
| 2K (Driver's Door Lock Link Switch) |
| Locked |
Battery Voltage |
| Unlocked |
No Voltage |
| 2L (Passenger's & Rear Door Lock Link Switches) |
| Locked |
No Continuity |
| Unlocked |
Continuity |
| 2M (Flasher Unit) |
| Hazard Switch Off |
Battery Voltage |
| Hazard Switch On |
No Voltage |
| 2N (Hood Switch) |
| Hood Closed |
No. Continuity |
| Hood Open |
Continuity |
| 2O (Trunk Lid Opener Relay) |
| .4 Sec. After TRUNK Pressed |
No Voltage |
| Other |
Battery Voltage |
| 2R (Keyless Unit) |
| .3 Sec. After LOCK Pressed |
3.5 Volt |
| .3 Sec. After UNLOCK Pressed |
1.7 Volt |
| .3 Sec. After TRUNK Pressed |
No Voltage |
| Other |
5 Volts |