GM Service Manual Online
For 1990-2009 cars only
Table 1: Vehicle Communication Unit (VCU)
Table 2: Vehicle Interface Unit (VIU) C1
Table 3: Vehicle Interface Unit (VIU) C2

Vehicle Communication Unit (VCU)


Object Number: 585586  Size: CH

Connector Part Information

    • AMP 205207-1
    • 25-Way F DB-25 (BLK)

Pin

Wire Color

Circuit No.

Function

1

DK GRN/WHT

965

Audio Transmit Signal

2

--

--

Not Used

3

GRY/BLK

1798

Low Reference

4

ORN

2240

Battery Positive Voltage

5

PPL/WHT

971

Ignition On Signal

6

BRN/WHT

964

Audio Return Signal

7-10

--

--

Not Used

11

LT BLU/BLK

970

Onstar Serial Data (+)

12

WHT

969

Onstar Serial Data (-)

13

--

--

Not Used

14

BARE

966

Drain Wire

15

GRY

967

Microphone Signal

16-17

--

--

Not Used

18

TAN/BLK

968

Onstar Serial Data Return

19-23

--

--

Not Used

24

DK BLU

981

Audio Low Reference

25

--

--

Not Used

Vehicle Interface Unit (VIU) C1


Object Number: 258912  Size: CH

Connector Part Information

    • 12110115
    • 32-Way F Micro-Pack 100 Series (RED)

Pin

Wire Color

Circuit No.

Function

A1

--

--

Not Used

A2

PPL

1807

Class 2 Serial Data

A3

DK GRN

835

Entertainment and Comfort Serial Data

A4-A5

--

--

Not Used

A6

BLK/WHT

372

Remote Radio Audio Output (-)

A7

DK GRN/WHT

368

Remote Radio Right Audio Signal

A8

BRN/WHT

367

Remote Radio Left Audio Signal

A9

BARE

1705

Drain Wire

A10

DK BLU

981

Audio Low Reference

A11

BRN/WHT

964

Audio Return Signal

A12

DK GRN/WHT

965

Audio Transmit Signal

A13

BARE

966

Drain Wire

A14

GRY/BLK

967

Microphone Signal

A15

BARE

1782

Drain Wire

A16

ORN

2240

Battery Positive Voltage

B1-B8

--

--

Not Used

B9

GRY

655

Cellular Microphone Signal

B10

BARE

1705

Drain Wire

B11

TAN/BLK

968

Onstar Serial Data Return

B12

WHT

969

Onstar Serial Data (-)

B13

LT BLU/BLK

970

Onstar Serial Data (+)

B14

GRY/BLK

1798

Low Reference

B15

PPL/WHT

971

Ignition On Signal

B16

--

--

Not Used

Vehicle Interface Unit (VIU) C2


Object Number: 73222  Size: CH

Connector Part Information

    • 12110113
    • 32-Way F Micro-Pack 150 Series (DK BLU)

Pin

Wire Color

Circuit No.

Function

E1

BLK

1351

Ground

E2-E3

--

--

Not Used

E4

DK GRN/WHT

2514

Keypad Signal

E5

YEL/BLK

2516

Keypad Green LED Signal

E6

LT GRN/BLK

2515

Keypad Supply Voltage

E7-E10

--

--

Not Used

E11

BLK

28

Horn Relay Control

E12-E13

--

--

Not Used

E14

BLK/WHT

624

Headlamp Alarm Signal

E15

--

--

Not Used

E16

ORN

2240

Battery Positive Voltage

F1

BLK

1351

Ground

F2- F8

--

--

Not Used

F9

BRN/WHT

2517

Keypad Red LED Signal

F10-F15

--

--

Not Used

F16

ORN

2240

Battery Positive Voltage