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Central Processing Unit (CPU): Millenia

  1. 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 . See appropriate CPU CONNECTOR PIN VOLTAGES & CONTINUITY table. Disconnect CPU connector and check continuity at specified terminals.
  2. If voltage 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. See CENTRAL PROCESSING UNIT (CPU)  under REMOVAL & INSTALLATION.
Fig 1: Identifying CPU Connector Terminals (Millenia)
G98J03927Courtesy of MAZDA MOTORS CORP.
CPU CONNECTOR PIN VOLTAGES & CONTINUITY (CONNECTOR "A")

Terminal Specification Or Condition
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
(1) Check continuity with ignition off and CPU connector disconnected.
(2) Measure voltage with CPU connector connected and ignition on, unless specified otherwise.
CPU CONNECTOR PIN VOLTAGES & CONTINUITY (CONNECTOR "B")

Terminal Specification Or Condition
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)
0.4 Sec. After Door Locked No Voltage
Other Battery Voltage
1H Not Used
1I (Door Lock Timer Unit) (2)
0.4 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
(1) Check continuity with ignition off and CPU connector disconnected.
(2) Measure voltage with CPU connector connected and ignition on, unless specified otherwise.
CPU CONNECTOR PIN VOLTAGES & CONTINUITY (CONNECTOR "C")

Terminal Specification Or Condition
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
(1) Check continuity with ignition off and CPU connector disconnected.
(2) Measure voltage with CPU connector connected and ignition on, unless specified otherwise.
(3) Hold key cylinder in UNLOCKED position.
CPU CONNECTOR PIN VOLTAGES & CONTINUITY (CONNECTOR "D")

Terminal Specification Or Condition
3A (Parking Brake Switch) (1)
Parking Brake On Continuity
Parking Brake Released No Continuity
3B (Keyless Unit), Not Operating (2) 1.28 K/Ohms
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 Continuity
Auto Switch Off No Continuity
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 Continuity
Manual Switch In Down Position Continuity
Other No Continuity
3I (Tilt Relay), Ignition On (2)
Manual Switch In Down Position No Voltage
Other Battery Voltage
3J (Tilt Sensor), Ignition On (2) .8-1.2 K/Ohms
3K (Tilt Sensor), Ignition On (2) .28-.91 K/Ohms
3L (Tilt Sensor), Ignition On (2) No Voltage
(1) Check continuity with ignition off and CPU connector disconnected.
(2) Measure voltage with CPU connector connected and ignition on, unless specified otherwise.
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