2004 Chevrolet Epica LSFACTORY OEM SERVICE PROCEDURE

Engine Control Module (ECM) Connector End Views

Engine Control Module (ECM) C1

GM1497745Courtesy of GENERAL MOTORS CORP.
Connector Part Information
  • AMP 368376
  • 81-Way F 81POS Receptacle Hsg Assembly (BK)
Pin Wire Color Circuit Number Function
1 - - Not Used
2 BK 251 Ground
3 D-BU 426 Idle Motor Feed
4 OG 440 Battery Positive Voltage
5 OG/BK 425 Idle Motor Return
6 D-GN/WH 817 Vehicle Speed Signal
7 D-BU/BK 480 Rough Road Signal
8 PU/WH 1665 Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 Signal
9 D-GN/WH 1664 Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2 Signal
10 YE 492 Mass Air Flow (MAF) Sensor Signal
11 D-GN/WH 1456 Exhaust Gas Recirculation (EGR) Valve Position Sensor Signal
12 L-GN 432 Manifold Absolute Pressure (MAP) Sensor Signal
13 RD/BK 380 A/C Pressure Sensor Signal
14-16 - - Not Used
17 D-BU/WH 1936 Fuel Level Sensor Signal
18 BN/WH 633 Camshaft Position (CMP) Sensor Signal
19 D-BU/WH 1869 Crankshaft Position (CKP) Signal
20 - - Not Used
21 RD 427 Idle Switch Position
22 WH/BK 1922 CAN Serial Data Low
23 D-GN/BK 2905 Serial Data
24 D-BU/BK 844 Fuel Injector 4 Control
25 D-GN/WH 762 A/C Request Signal
26 PU 1666 Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1 Signal
27 D-GN 1663 Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 Signal
28 D-BU/WH 417 Idle Motor Position Signal
29 D-GN 534 Throttle Position (TP) Sensor Signal
30 - - Not Used
31 BN 472 Intake Air Temperature (IAT) Sensor Signal
32-35 - - Not Used
36 YE 410 Engine Coolant Temperature (ECT) Sensor Signal
37 - - Not Used
38 YE/BK 1868 Low Reference
39 - - Not Used
40 WH/BK 448 Keyword Serial Data
41 YE/BK 1921 CAN Serial Data High
42 YE/BK 846 Fuel Injector 6 Control
43 L-GN/BK 1745 Fuel Injector 2 Control
44 BK/WH 1057 Shield Ground
45-47 - - Not Used
48 GY/BK 469 5-Volt Reference
49 GY 416 5-Volt Reference
50 GY 474 5-Volt Reference
51 GY/BK 605 Low Reference
52 D-GN 890 Fuel Tank Pressure (FTP) Sensor Signal
53-59 - - Not Used
60 GY/BK 435 Exhaust Gas Recirculation (EGR) Solenoid Control
61 D-BU/BK 845 Fuel Injector 5 Control
62 BK 1744 Fuel Injector 1 Control
63 D-BU/WH 1876 Knock Sensor 2 Signal
64 WH 496 Knock Sensor 1 Signal
65 BK 470 Low Reference
66 BK 650 Low Reference
67 BK 750 Low Reference
68 L-BU/BK 808 Low Reference
69 YE/BK 452 Low Reference
70 D-BU/BK 632 Low Reference
71 BK/WH 645 Low Reference
72-75 - - Not Used
76 BK 1704 Low Reference
77 - - Not Used
78 BK/WH 251 Ground
79 PK/D-BU 539 Ignition 1 Voltage
80 D-GN/WH 428 EVAP Canister Purge Valve Solenoid Control
81 RD/BK 1746 Fuel Injector 3 Control
Engine Control Module (ECM) C2

GM1497768Courtesy of GENERAL MOTORS CORP.
Connector Part Information
  • AMP 368383
  • 40-Way F 40POS Receptacle Hsg Assembly (BK)
Pin Wire Color Circuit Number Function
82 - - Not Used
83 BK/WH 251 Ground
84 - - Not Used
85 D-GN 135 Engine Coolant Temperature (ECT) Sensor Signal
86-87 - - Not Used
88 BK/WH 251 Ground
89 BN 1667 Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1 Heater Control
90-91 - - Not Used
92 PU/WH 1885 MIL Control
93 D-GN 335 Low Speed Cooling Fan Relay Control
94 WH/BK 1655 Heated Oxygen Sensor (HO2S) Bank 2 Sensor 2 Heater Control
95-96 - - Not Used
97 BN/WH 1653 Heated Oxygen Sensor (HO2S) Bank 1 Sensor 1 Heater Control
98 - - Not Used
99 D-GN/WH 465 Fuel Pump Relay Control
100 - - Not Used
101 WH 121 Engine Speed Signal
102 D-BU 473 High Speed Cooling Fan Relay Control
103-104 - - Not Used
105 WH 1654 Heated Oxygen Sensor (HO2S) Bank 2 Sensor 1 Heater Control
106 PU/WH 67 A/C Clutch Relay Control
107 YE 130 Fuel Level Sensor Signal
108 WH/BK 962 Intake Manifold Tuning Valve Solenoid Control
109 - - Not Used
110 OG/BK 1029 Main Relay Control
111-112 - - Not Used
113 PU 1986 EVAP Canister Vent Solenoid Control
114 BK 350 Ground
115 L-BU 1153 Ignition Coil 1 Control
116 D-BU 1154 Ignition Coil 2 Control
117 D-GN 1157 Ignition Coil 5 Control
118 GY 1158 Ignition Coil 6 Control
119 PK/BK 1846 Main Relay Voltage
120 RD 1156 Ignition Coil 4 Control
121 YE 1155 Ignition Coil 3 Control
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.