GM Service Manual Online
For 1990-2009 cars only
Connector 1: Engine Control Module (ECM) C1
Connector 2: Engine Control Module (ECM) C2
Connector 3: Engine Control Module (ECM) C3

Engine Control Module (ECM) C1


Object Number: 1228485  Size: CH

Connector Part Information

  • OEM: 34576-3503
  • Service: 88988367
  • Description: 56-Way F Micro-Pack 64 Series Sealed (BU)

Terminal Part Information

  • Pins: 2, 6, 7, 9, 12, 13, 18-20, 33-37, 40, 44, 47-49, 53, 55, 56
  • Terminal/Tray: 15359541/4
  • Core/Insulation Crimp: M/M
  • Release Tool/Test Probe: 15381651-2/J-35616-64B (L-BU)

Engine Control Module (ECM) C1

Pin

Wire Color

Circuit No.

Function

1

--

--

Not Used

2

PU

420

TCC Brake Switch/Cruise Control Release Signal

3-5

--

--

Not Used

6

BN/WH

379

Cruise Control Clutch Pedal Position Switch Signal

7

L-BU

20

Stop Lamp Supply Voltage

8

--

--

Not Used

9

TN

2759

Low Reference

10-11

--

--

Not Used

12

BN/WH

419

MIL Control

13

D-GN/WH

465

Fuel Pump Relay Control

14-17

--

--

Not Used

18

BN

4

Accessory Voltage

19

PK

1039

Ignition 1 Voltage

20

RD/WH

840

Battery Positive Voltage

21-32

--

--

Not Used

33

WH/BK

1164

5-Volt Reference

34

GY

2709

5-Volt Reference

35

TN

1274

5-Volt Reference

36

BN

1271

Low Reference

37

PU

1272

Low Reference

38-39

--

--

Not Used

40

BN

5069

Powertrain Relay Control

41-43

--

--

Not Used

44

PU

1589

Fuel Level Sensor Signal

45-46

--

--

Not Used

47

D-BU

1161

APP Sensor 1 Signal

48

D-GN

890

Fuel Tank Pressure Sensor Signal

49

L-BU

1162

APP Sensor 2 Signal

50-52

--

--

Not Used

53

D-GN/WH

459

A/C Compressor Clutch Relay Control

54

--

--

Not Used

55

WH

1310

EVAP Canister Vent Solenoid Control

56

YE

447

Starter Relay Coil Control

Engine Control Module (ECM) C2


Object Number: 1335545  Size: CH

Connector Part Information

  • OEM: 34566-2503
  • Service: 88988931
  • Description: 73-Way F Micro-Pack 64 Series Sealed (BK)

Terminal Part Information

  • Pins: 1-5, 8, 9, 11-14, 17, 20, 23, 27, 29, 30, 32, 33, 35, 36, 39, 42-44, 46, 48, 50, 53, 56, 59, 62-64, 66-69, 71, 72
  • Terminal/Tray: See Terminal Repair Kit
  • Core/Insulation Crimp: See Terminal Repair Kit
  • Release Tool/Test Probe: See Terminal Repair Kit
  • Pins: 73
  • Terminal/Tray: 7116-4152-02/9
  • Core/Insulation Crimp: 2/5
  • Release Tool/Test Probe: 12094430/J-35616-35 (VT)

Engine Control Module (ECM) C2

Pin

Wire Color

Circuit No.

Function

1

PU

2121

Ignition Control (1)

2

TN/WH

3111

Heated Oxygen Sensor Low Signal Sensor 1

3

PU/WH

3110

Heated Oxygen Sensor High Signal Sensor 1

4

PU/WH

1668

Heated Oxygen Sensor High Signal Sensor 2

5

TN/WH

1669

Heated Oxygen Sensor Low Signal Sensor 2

6-7

--

--

Not Used

8

D-BU

496

Knock Sensor Signal

9

GY

1716

Knock Sensor Signal

10

--

--

Not Used

11

YE

581

TAC Motor Control (1)

12

BN

582

TAC Motor Control (2)

13

PK/BK

5290

Ignition 1 Voltage

14

PK/BK

6395

CMP Actuator Solenoid Control Intake

15-16

--

--

Not Used

17

L-BU

2123

Ignition Control (3)

18-19

--

--

Not Used

20

GY

5296

Low Reference

21-22

--

--

Not Used

23

TN

5301

Low Reference

24-26

--

--

Not Used

27

PU

574

Low Reference

28

--

--

Not Used

29

TN

2752

Low Reference

30

L-GN

5282

Low Reference

31

--

--

Not Used

32

L-GN/BK

1745

Fuel Injector (2) Control

33

D-GN/WH

2124

Ignition Control (4)

34

--

--

Not Used

35

BN

2129

Low Reference

36

YE/BK

5297

5-Volt Reference

37-38

--

--

Not Used

39

D-BU

5300

5-Volt Reference

40-41

--

--

Not Used

42

TN

2760

Low Reference

43

L-GN

2867

5-Volt Reference

44

GY

2701

5-Volt Reference

45

--

--

Not Used

46

PU

5284

Low Reference

47

--

--

Not Used

48

PK/BK

1746

Fuel Injector Control (3)

49

--

--

Not Used

50

WH/BK

6396

CMP Actuator Solenoid Control Exhaust

51-52

--

--

Not Used

53

OG/WH

2122

Ignition Control (2)

54-55

--

--

Not Used

56

D-GN

5273

CMP Sensor Signal

57-58

--

--

Not Used

59

OG

5275

CMP Sensor Signal

60-61

--

--

Not Used

62

TN

472

Intake Air Temperature Sensor Signal

63

YE

573

Crankshaft Position Sensor Signal

64

D-GN

485

Throttle Position Sensor (1) Signal

65

--

--

Not Used

66

PU

486

Throttle Position Sensor (2) Signal

67

YE

492

Mass Air Flow Sensor Signal

68

GY/WH

3113

Heated Oxygen Sensor Heater Low Control Sensor 1

69

GY/WH

3122

Heated Oxygen Sensor Heater Low Control Sensor 2

70

--

--

Not Used

71

L-BU/BK

844

Fuel Injector (4) Control

72

TN

1744

Fuel Injector (1) Control

73

BK/WH

451

Signal Ground

Engine Control Module (ECM) C3


Object Number: 1335545  Size: CH

Connector Part Information

  • OEM: 34566-2603
  • Service: 88988372
  • Description: 73-Way F Micro-Pack 64 Series Sealed (GY)

Terminal Part Information

  • Pins: 7, 21, 23, 28, 29, 33, 35, 37, 39, 44, 47-49, 53, 55, 57, 59, 65-67
  • Terminal/Tray: See Terminal Repair Kit
  • Core/Insulation Crimp: See Terminal Repair Kit
  • Release Tool/Test Probe: See Terminal Repair Kit

Engine Control Module (ECM) C3

Pin

Wire Color

Circuit No.

Function

1-6

--

--

Not Used

7

OG

225

Generator Turn On Signal

8-20

--

--

Not Used

21

BK/WH

2751

Low Reference

22

--

--

Not Used

23

OG/BK

469

Low Reference

24-27

--

--

Not Used

28

TN/WH

1704

Low Reference

29

GY

23

Generator Field Duty Cycle Signal

30-32

--

--

Not Used

33

TN

2501

High Speed GMLAN Serial Data (-) (1)

34

--

--

Not Used

35

TN

2761

Low Reference

36

--

--

Not Used

37

GY

2700

5-Volt Reference

38

--

--

Not Used

39

GY

2704

5-Volt Reference

40-43

--

--

Not Used

44

L-BU/BK

1688

5-Volt Reference

45-46

--

--

Not Used

47

D-GN

1433

PNP/Clutch Start Switch Signal (M86)

48

D-GN/WH

428

EVAP Canister Purge Solenoid Control

49

D-GN

335

Low Speed Cooling Fan Relay Control

50-52

--

--

Not Used

53

TN/BK

2500

High Speed GMLAN Serial Data (+) (1)

54

--

--

Not Used

55

YE

410

Engine Coolant Temperature Sensor Signal

56

--

--

Not Used

57

OG/BK

380

A/C Refrigerant Pressure Sensor Signal

58

--

--

Not Used

59

L-GN

432

Manifold Absolute Pressure Sensor Signal

60-64

--

--

Not Used

65

TN/BK

231

Oil Pressure Switch Signal

66

YE

400

Vehicle Speed Sensor Signal High (w/M86)

67

PU

401

Vehicle Speed Sensor Low (w/M86)

68-73

--

--

Not Used