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 Fig 1 -Fig 5 . See appropriate CPU CONNECTOR PIN VOLTAGES & CONTINUITY table. 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 and wiring harnesses are okay, but system is still not functioning properly, replace CPU.
Fig 2: Identifying CPU Connector "A" (16-Pin) Terminals (MPV) & Joint Box Connector No. 1 (16-Pin) Terminals (626)
Fig 3: Identifying CPU Connector "B" (16-Pin) Terminals (MPV) & Connector No. 2 (16-Pin) Terminals (626)
CPU CONNECTOR PIN VOLTAGES & CONTINUITY
| Terminal | Specification Or Condition | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Connector "A" (16-Pin) | |||||||||
| A (Hood Switch) (1) | |||||||||
| Hood Closed | No Continuity | ||||||||
| Hood Open | Continuity | ||||||||
| B (Starter Cut Relay), Constant (2) | Battery Voltage | ||||||||
| C (10-Amp RADIO Fuse), Constant (2) | Battery Voltage | ||||||||
| D | Not Used | ||||||||
| E (Rear Door Switch) (1) | |||||||||
| Rear Doors Closed | No Continuity | ||||||||
| Any Rear Door Open | Continuity | ||||||||
| F (Horn Relay) (2) | |||||||||
| Horn Sounding | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| G (CPU Ground), Constant (1) | Continuity | ||||||||
| H (Key Reminder Switch) (2) | |||||||||
| Key Inserted | Battery Voltage | ||||||||
| Key Removed | No Voltage | ||||||||
| I | Not Used | ||||||||
| J (15-Amp ROOM Fuse), Constant (2) | Battery Voltage | ||||||||
| K (Interior & Spot Light) (2) | |||||||||
| Switch In Door Position | Battery Voltage | ||||||||
| Other | No Voltage | ||||||||
| L (TNS Relay) (2) | |||||||||
| Headlights On | Battery Voltage | ||||||||
| Other | No Voltage | ||||||||
| N (15-Amp METER Fuse), Constant (2) | Battery Voltage | ||||||||
| O | Not Used | ||||||||
| P | Not Used | ||||||||
| Connector "B" (16-Pin) | |||||||||
| 1A | Not Used | ||||||||
| 1B (Trunk Key Cylinder Switch) (1) | |||||||||
| Locked | No Continuity | ||||||||
| Unlocked | Continuity | ||||||||
| 1C (Headlight Relay) (2) | |||||||||
| Headlights Off | Battery Voltage | ||||||||
| Headlights On | No Voltage | ||||||||
| 1D (Trunk Compartment Light Switch) (2) | |||||||||
| Trunk Lid Closed | Battery Voltage | ||||||||
| Trunk Lid Open | No Voltage | ||||||||
| 1E (Flasher Unit) (2) | |||||||||
| Hazard Switch Off | Battery Voltage | ||||||||
| Hazard Switch On | No Voltage | ||||||||
| 1F | Not Used | ||||||||
| 1G (Door Lock Timer Unit) (2) | |||||||||
| .4 Sec. After Door Locked | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 1H | Not Used | ||||||||
| 1I (Door Lock Timer Unit) (2) | |||||||||
| .4 Sec. After Door Unlocked | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 1J | Not Used | ||||||||
| 1K | Not Used | ||||||||
| 1L (Fog Light Relay) (2) | |||||||||
| Fog Light Switch On | No Voltage | ||||||||
| Fog Light Switch Off | Battery Voltage | ||||||||
| 1M (Fog Light Switch - On) (1) | |||||||||
| Fog Light Switch Pushed | Continuity | ||||||||
| Fog Light Switch Released | No Continuity | ||||||||
| 1N (Fog Light Switch - Off) (1) | |||||||||
| Fog Light Switch Pushed | Continuity | ||||||||
| Fog Light Switch Released | No Continuity | ||||||||
| 1O | Not Used | ||||||||
| 1P (Keyless Unit), Not Operating (2) | 5 Volts | ||||||||
| Connector "C" (20-Pin) | |||||||||
| 2A (Key Interlock Solenoid), Ignition On (2) | |||||||||
| Selector In "R" Position | No Voltage | ||||||||
| Selector In "P" Position | Battery Voltage | ||||||||
| 2B (Key Interlock Solenoid), Ignition On (2) | |||||||||
| Selector In "P" Position | Battery Voltage | ||||||||
| Selector Not In "P" Position | No Voltage | ||||||||
| 2C ("P" Range Switch), Ignition On (2) | |||||||||
| Selector In "P" Position | 5 Volts | ||||||||
| Selector Not In "P" Position | No Voltage | ||||||||
| 2D (Passenger's Door Switch) (1) | |||||||||
| Door Closed | No Continuity | ||||||||
| Door Open | Continuity | ||||||||
| 2E | Not Used | ||||||||
| 2F | Not Used | ||||||||
| 2G (Trunk Lid Opener Relay) (2) | |||||||||
| .27 Sec. After TRUNK Pressed | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 2H (Driver's Door Lock Link Switch) (2) | |||||||||
| Locked | 5 Volts | ||||||||
| Unlocked | No Voltage | ||||||||
| 2L (Door Lock Switch) (2) | |||||||||
| Locked | 2.5 Volts | ||||||||
| Unlocked (3) | No Voltage | ||||||||
| Other | 5 Volts | ||||||||
| 2M (Security Light) (2) | |||||||||
| Light Off | Battery Voltage | ||||||||
| Light On | No Voltage | ||||||||
| 2N | Not Used | ||||||||
| 2O | Not Used | ||||||||
| 2P (Passenger's Door Key Cylinder Switch) (2) | |||||||||
| Locked | 2.5 Volts | ||||||||
| Unlocked (3) | No Voltage | ||||||||
| Other | 5 Volts | ||||||||
| 2Q | Not Used | ||||||||
| 2R (Driver's Door Key Cylinder Switch) (2) | |||||||||
| Locked | 2.5 Volts | ||||||||
| Unlocked (3) | No Voltage | ||||||||
| Other | 5 Volts | ||||||||
| 2S | Not Used | ||||||||
| 2T (Driver's Door Switch) (1) | |||||||||
| Door Closed | No Continuity | ||||||||
| Door Open | Continuity | ||||||||
| Connector "D" (12-Pin) | |||||||||
| 3A (Parking Brake Switch) (1) | |||||||||
| Parking Brake On | Continuity | ||||||||
| Parking Brake Released | No Continuity | ||||||||
| 3B (Keyless Unit), Not Operating (2) | 5 Volts | ||||||||
| 3C (Door Lock Timer Unit) (2) | |||||||||
| 4 Sec. After UNLOCK (Driver) Pressed | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 3D | Not Used | ||||||||
| 3E (DRL Relay) (2) | |||||||||
| Parking Brake On | Battery Voltage | ||||||||
| Parking Brake Released | No Voltage | ||||||||
| 3F (Tilt Switch), Ignition On (2) | |||||||||
| Auto Switch On | No Voltage | ||||||||
| Auto Switch Off | Battery Voltage | ||||||||
| 3G (Tilt Relay), Ignition On (2) | |||||||||
| Manual Switch In Up Position | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 3H (Tilt Switch), Ignition On (2) | |||||||||
| Manual Switch In Up Position | No Voltage | ||||||||
| Manual Switch In Down Position | 2.85 Volts | ||||||||
| Other | 5 Volts | ||||||||
| 3I (Tilt Relay), Ignition On (2) | |||||||||
| Manual Switch In Down Position | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 3J (Tilt Sensor), Ignition On (2) | 5 Volts | ||||||||
| 3K (Tilt Sensor), Ignition On (2) | |||||||||
| Steering Wheel Tilted Up | 4.3 Volts | ||||||||
| Steering Wheel Tilted Down | 1.3 Volts | ||||||||
| 3L (Tilt Sensor), Ignition On (2) | No Voltage | ||||||||
|
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CPU CONNECTOR PIN VOLTAGES & CONTINUITY
| Terminal | Specification Or Condition | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Connector "A" (16-Pin) | |||||||||
| 1A (Rear Wiper) (1) | |||||||||
| Ignition ON | Battery Voltage | ||||||||
| Ignition In LOCK Or ACC | No Voltage | ||||||||
| 1B (Idle Up, Fan Switch) (2) | |||||||||
| Fan Switch OFF Or 1 | No Continuity | ||||||||
| Fan Switch 2, 3 Or 4 | Continuity | ||||||||
| 1C (ACC) (1) | |||||||||
| Ignition ACC Or ON | Battery Voltage | ||||||||
| Ignition LOCK | No Voltage | ||||||||
| 1D (Idle Up, Headlight Switch) (1) | |||||||||
| Headlight Switch 2nd Position | Battery Voltage | ||||||||
| Headlight Switch OFF Or 1st Position | No Voltage | ||||||||
| 1E (Shift Lock, Shift Lock Solenoid) (1) | |||||||||
| Ignition ON | Battery Voltage | ||||||||
| Ignition LOCK Or ACC | No Voltage | ||||||||
| 1F (Idle Up, PCM) (1) | |||||||||
| Ignition ON | Battery Voltage | ||||||||
| Ignition LOCK Or ACC | No Voltage | ||||||||
| 1G (CPU Ground), Constant (2) | Continuity | ||||||||
| 1H (Shift Lock, Brake Switch) (1) | |||||||||
| Brake Depressed | Battery Voltage | ||||||||
| Brake Released | No Voltage | ||||||||
| 1I (Shift Lock, TRS) (1) | |||||||||
| Ignition ACC, Gear Selector "P" | Battery Voltage | ||||||||
| Ignition ACC, Gear Selector Except "P" | No Voltage | ||||||||
| 1J (Power Supply), Constant (1) | Battery Voltage | ||||||||
| 1K (Key Reminder) (1) | |||||||||
| Key In | Battery Voltage | ||||||||
| Key Out | No Voltage | ||||||||
| 1L (TNS) (1) | |||||||||
| Headlight Switch 1st Or 2nd Position | Battery Voltage | ||||||||
| Headlight Switch OFF Position | No Voltage | ||||||||
| 1M (IG1) (1) | |||||||||
| Ignition ON | Battery Voltage | ||||||||
| Ignition LOCK Or ACC | No Voltage | ||||||||
| 1N (Seat Belt Buckle Switch) (2) | |||||||||
| Seat Belt Fastened | No Continuity | ||||||||
| Seat Belt Unfastened | Continuity | ||||||||
| 1O (Door Open/Closed) (2) | |||||||||
| Any Door Open | Continuity | ||||||||
| All Doors Closed | No Continuity | ||||||||
| 1P (Idle Up, Rear Defroster) (2) | |||||||||
| Rear Defroster On | Continuity | ||||||||
| Rear Defroster Off | No Continuity | ||||||||
| Connector "B" (16-Pin) | |||||||||
| 2A (Door Lock Link Switch) (2) | |||||||||
| Driver's Door Locked | Continuity | ||||||||
| Driver's Door Unlocked | No Continuity | ||||||||
| 2B (Door Lock Timer Unit) (1) | |||||||||
| While Driver's Door Lock Is Unlocking | No Voltage | ||||||||
| All Other | Battery Voltage | ||||||||
| 2C (Door Lock Timer Unit) (1) | |||||||||
| While Driver's Door Lock Is Locking | No Voltage | ||||||||
| All Other | Battery Voltage | ||||||||
| 2D (DRL Relay) (1)(3) | |||||||||
| Parking Brake Applied | Battery Voltage | ||||||||
| Parking Brake Released | No Voltage | ||||||||
| 2E (Door Lock Timer Unit) (1) | |||||||||
| While Driver's Door Lock Is Unlocking | No Voltage | ||||||||
| All Other | Battery Voltage | ||||||||
| 2F (Horn Relay) (1) | |||||||||
| Horn Switch Pushed | Battery Voltage | ||||||||
| Horn Switch Released | No Voltage | ||||||||
| 2G (Door Lock Link Switch) (2) | |||||||||
| Driver's Door Locked | No Continuity | ||||||||
| Driver's Door Unlocked | Continuity | ||||||||
| 2H (Not Used) | |||||||||
| 2I (DRL, Parking Brake Switch) (2)(3) | |||||||||
| Parking Brake Applied | Continuity | ||||||||
| Parking Brake Released | No Continuity | ||||||||
| 2J (Not Used) | |||||||||
| 2K (BRAKE Warning Light) (2)(3) | |||||||||
| Parking Brake Applied | No Voltage | ||||||||
| Parking Brake Released | Battery Voltage | ||||||||
| 2L (Dome Light) (1) | |||||||||
| Dome Light Switch In DOOR Position | Battery Voltage | ||||||||
| Other | No Voltage | ||||||||
| 2M (Rear Wiper Switch) (2) | |||||||||
| Rear Wiper On | Continuity | ||||||||
| Rear Wiper Off | No Continuity | ||||||||
| 2N (Keyless Unit), Constant (1) | 5 Volts | ||||||||
| 20 (Rear Washer Switch) (2) | |||||||||
| Rear Washer On | Continuity | ||||||||
| Rear Washer Off | No Continuity | ||||||||
| 2P (Not Used) | |||||||||
|
|||||||||
CPU CONNECTOR PIN VOLTAGES & CONTINUITY
| Terminal Connector No. 1 (16-Pin) | Specification Or Condition | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1A (Trunk Light Switch) (1) | |||||||||
| Trunk Open | No Voltage | ||||||||
| Trunk Closed | Battery Voltage | ||||||||
| 1B (Key Reminder Switch) (1) | |||||||||
| Key Inserted | No Voltage | ||||||||
| Key Removed | Battery Voltage | ||||||||
| 1C (15-Amp RADIO Fuse) (1) | |||||||||
| ACC Or ON Position | Battery Voltage | ||||||||
| LOCK Position | No Voltage | ||||||||
| 1D (Brake Warning Light), Ignition On (1) | |||||||||
| Brake Fluid Level Below MIN | Battery Voltage | ||||||||
| Brake Fluid Level Above MIN | No Voltage | ||||||||
| 1E (Rear Defroster Light), Ignition On (1) | |||||||||
| ON Position | Battery Voltage | ||||||||
| ACC Or LOCK Position | No Voltage | ||||||||
| 1F (Interior Light) (1) | |||||||||
| Switch In DOOR Position | Battery Voltage | ||||||||
| Switch In ON Or OFF Position | No Voltage | ||||||||
| 1G (CPU Ground), Constant (2) | Continuity | ||||||||
| 1H (Door Ajar Light) (1) | |||||||||
| ON Position | Battery Voltage | ||||||||
| ACC Or LOCK Position | No Voltage | ||||||||
| 1I (Door Switch) (2) | |||||||||
| All Doors Closed | No Continuity | ||||||||
| Any Door Open | Continuity | ||||||||
| 1J (15-Amp ROOM Fuse), Constant (1) | Battery Voltage | ||||||||
| 1K (Door Lock Switch) (1) | |||||||||
| Locked Or Unlocked | Continuity | ||||||||
| Released | No Continuity | ||||||||
| 1L | Not Used | ||||||||
| 1M (10-Amp METER Fuse) (1) | |||||||||
| ON Position | Battery Voltage | ||||||||
| ACC Or LOCK Position | No Voltage | ||||||||
| 1N (Rear Defroster Switch) (1) | |||||||||
| Switch Pushed | Continuity | ||||||||
| Switch Released | No Continuity | ||||||||
| 1O (Seat Belt Light/Buckle Switch), Ignition On (1) | |||||||||
| Driver's Belt Buckled | Battery Voltage | ||||||||
| Driver's Belt Unbuckled | No Voltage | ||||||||
| 1P (Parking Brake Switch) (2) | |||||||||
| Parking Brake On | Battery Voltage | ||||||||
| Parking Brake Released | No Voltage | ||||||||
| Connector No. 2 (16-Pin) | |||||||||
| 2A (Horn Relay/Horn Switch) (1) | |||||||||
| Horn Off | Battery Voltage | ||||||||
| Horn On | No Voltage | ||||||||
| 2B (Door Lock Timer Unit 1 - Door Lock) (1) | |||||||||
| While Pressing Switch | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 2C (Security Light) (1) | |||||||||
| Light Off | Battery Voltage | ||||||||
| Light On | No Voltage | ||||||||
| 2D (Door Lock Timer Unit 2 - Trunk Unlock) (1) | |||||||||
| While Pressing Switch | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 2E (Flasher Unit) (1) | |||||||||
| Hazard Switch Off | Battery Voltage | ||||||||
| Hazard Switch On | No Voltage | ||||||||
| 2F (Door Lock Timer Unit 2 - Driver's Door Unlock) (1) | |||||||||
| While Pressing Switch | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 2G | Not Used | ||||||||
| 2H (Door Lock Timer Unit 1 - Door Unlock) (1) | |||||||||
| While Pressing Switch | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 2I | Not Used | ||||||||
| 2J (Trunk Key Cylinder Switch) (2) | |||||||||
| Locked | No Continuity | ||||||||
| Unlocked (3) | Continuity | ||||||||
| 2K | Not Used | ||||||||
| 2L | Not Used | ||||||||
| 2M | Not Used | ||||||||
| 2N | Not Used | ||||||||
| 2O (Keyless Unit) (1) | |||||||||
| .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 | ||||||||
| 2P | Not Used | ||||||||
| Connector No. 3 (8-Pin) | |||||||||
| 3A (Headlight Relay) (1) | |||||||||
| Headlights Off | Battery Voltage | ||||||||
| Headlights On | No Voltage | ||||||||
| 3B (Headlight Switch) (1) | |||||||||
| Headlights Off | 5 Volts | ||||||||
| Headlights On | No Voltage | ||||||||
| 3C (Hood Switch) (1) | |||||||||
| Hood Closed | 5 Volts | ||||||||
| Hood Open | No Voltage | ||||||||
| 3D | Not Used | ||||||||
| 3F (Rear Defroster Relay), Ignition On (2) | |||||||||
| Switch On | Battery Voltage | ||||||||
| Other | No Voltage | ||||||||
| 3H | Not Used | ||||||||
| 3I (Headlight Switch/TNS) (1) | |||||||||
| Headlight Switch Off | 5 Volts | ||||||||
| Headlight Switch In Park Or On Position | No Voltage | ||||||||
| 3J (TNS Relay) (1) | |||||||||
| Headlight Switch Off | Battery Voltage | ||||||||
| Headlight Switch In Park Or On Position | No Voltage | ||||||||
| Connector No. 4 (12-Pin) | |||||||||
| 4A (Left Headlight - Headlights On) (1) | |||||||||
| Dimmer At Low | No Voltage | ||||||||
| Dimmer At High | Battery Voltage | ||||||||
| 4B (CPU Ground), Constant (2) | Continuity | ||||||||
| 4C (Right Headlight - Headlights On) (1) | |||||||||
| Dimmer At Low | No Voltage | ||||||||
| Dimmer At High | Battery Voltage | ||||||||
| 4D (CPU Ground), Constant (2) | Continuity | ||||||||
| 4E (Headlight Relay) (1) | |||||||||
| Headlights Off | Battery Voltage | ||||||||
| Headlights On | No Voltage | ||||||||
| 4F (Headlight Switch) (1) | |||||||||
| Headlights Off | 5 Volts | ||||||||
| Headlights On | No Voltage | ||||||||
| 4H (High Beam Switch) (1) | |||||||||
| Dimmer At Low | 5 Volts | ||||||||
| Dimmer At High | No Voltage | ||||||||
| 4J (Rear Defroster Relay), Ignition On (2) | |||||||||
| Switch On | No Voltage | ||||||||
| Other | Battery Voltage | ||||||||
| 4K (Headlight High Relay - Headlights On) (1) | |||||||||
| Dimmer At Low | Battery Voltage | ||||||||
| Dimmer At High | No Voltage | ||||||||
| 4L | Not Used | ||||||||
| 4M (Headlight Switch/TNS) (1) | |||||||||
| Headlight Switch Off | 5 Volts | ||||||||
| Headlight Switch In Park Or On Position | No Voltage | ||||||||
| 4N (TNS Relay) (1) | |||||||||
| Headlight Switch Off | Battery Voltage | ||||||||
| Headlight Switch In Park Or On Position | No Voltage | ||||||||
|
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