2008 Cadillac STS VFACTORY OEM SERVICE PROCEDURE

Engine Control Module (ECM) X2 (LC3)

Fig 1: Engine Control Module (ECM) X2 (LC3) Connector End View
GM1650395Courtesy of GENERAL MOTORS CORP.
Engine Control Module (ECM) X2 (LC3)

Pin Wire Circuit Function
1 0.8 PU 2121 IC 1 Control
2 0.5 TN/WH 3111 HO2S Low Signal (Bank 1 Sensor 1)
3 0.5 PU/WH 3110 HO2S High Signal (Bank 1 Sensor 1)
4 0.5 PU 3120 HO2S High Signal (Bank 1 Sensor 2)
5 0.5 TN/WH 3121 HO2S Low Signal (Bank 1 Sensor 2)
6 0.5 L-BU 1876 Knock Sensor 2 Signal
7 0.5 GY 2303 Knock Sensor 2 Signal
8 0.35 D-BU 496 Knock Sensor 1 Signal
9 0.5 GY 1716 Knock Sensor 1 Signal
10 - - Not Used
11 0.75 YE 581 TAC Motor Control - 1
12 0.75 BN 582 TAC Motor Control - 2
13 0.75 PK/BK 5290 Ignition 1 Voltage
14 0.35 PK/BK 6395 Camshaft Position (CMP) Actuator Solenoid - Intake Bank 1 Control
15 0.35 TN/BK 6397 Camshaft Position (CMP) Actuator Solenoid - Intake Bank 2 Control
16 0.35 D-BU/WH 878 Fuel Injector 8 Control
17 0.8 OG/WH 2122 IC 2 Control
18 0.5 L-BU/WH 2126 IC 6 Control
19 0.8 BN/WH 2130 Low Reference
20 0.5 PU 6267 Low Reference
21 0.5 TN 6268 Low Reference
22 0.5 WH 6269 Low Reference
23 0.5 BN 6266 Low Reference
24 0.5 BK 2755 Low Reference
25 0.35 D-GN 7125 Super Charger Inlet Air Pressure Sensor Return
26 - - Not Used
27 0.5 GY/BK 6272 Low Reference
28 0.75 PK/BK 5290 Ignition 1 Voltage
29 0.5 TN 2752 Low Reference
30 0.35 BN/WH 6754 Low Reference
31 0.35 D-BU/WH 6756 Low Reference
32 0.8 PK/BK 1746 Fuel Injector 3 Control
33 0.8 OG 2127 IC 7 Control
34 0.8 D-GN 2125 IC 5 Control
35 0.8 BN 2129 Low Reference
36 0.5 D-GN 6457 5-Volt Reference
37 0.5 OG 6260 5-Volt Reference
38 0.5 PK 6261 5-Volt Reference
39 0.5 D-GN 6259 5-Volt Reference
40 0.35 GY 2705 5-Volt Reference
41 0.35 YE/BK 7124 5-Volt Reference
42 0.5 TN 2760 Low Reference
43 0.5 PU/WH 6270 5-Volt Reference
44 0.5 GY 2701 5-Volt Reference
45 0.35 BN 6273 Oil Temperature Sensor Low Reference
46 0.35 BN 6753 Low Reference
47 0.35 D-BU 6755 Low Reference
48 0.8 L-GN/BK 1745 Fuel Injector 2 Control
49 0.8 TN/WH 845 Fuel Injector 5 Control
50 0.35 WH/BK 6396 Camshaft Position (CMP) Actuator Solenoid - Exhaust Bank 1 Control
51 0.35 GY/BK 6394 Camshaft Position (CMP) Actuator Solenoid - Exhaust Bank 2 Control
52 0.8 L-BU/BK 844 Fuel Injector 4 Control
53 0.8 L-BU 2123 IC 3 Control
54 0.35 D-GN/WH 2124 IC 4 Control
55 0.35 PU/WH 2128 IC 5 Control
56 0.35 D-GN/WH 6264 Camshaft Position (CMP) Sensor - Exhaust Bank 1 Signal
57 0.35 OG/BK 6263 Camshaft Position (CMP) Sensor - Intake Bank 2 Signal
58 0.35 PK/BK 6262 Camshaft Position (CMP) Sensor - Exhaust Bank 2 Signal
59 0.35 D-BU/WH 6265 Camshaft Position (CMP) Sensor - Intake Bank 1 Signal
60 0.5 TN/WH 331 Oil Pressure Sensor Signal
61 - - Not Used
62 0.35 TN 472 IAT Sensor Signal
63 0.35 WH/BK 6271 CKP Sensor Signal
64 0.5 D-GN 485 TP Sensor 1 Signal
65 0.35 D-GN/WH 357 TCC Release Switch Signal
66 0.5 PU 486 TP Sensor 2 Signal
67 0.5 YE 492 MAF Sensor Signal
68 0.5 GY/WH 3113 HO2S Heater Low Control (Bank 1 Sensor 1)
69 0.5 GY/WH 3122 HO2S Heater Low Control (Bank 2 Sensor 1)
70 0.8 YE/BK 846 Fuel Injector 6 Control
71 0.8 OG/BK 877 Fuel Injector 7 Control
72 0.8 TN 1744 Fuel Injector 1 Control
73 2 BK/WH 1551 Ground
Connector Part Information 
  • OEM: 34566-0103
  • Service: 88988931
  • Description: 73-Way F (BK)
Terminal Part Information 
  • Pins: 1-9, 11-12, 14-25, 27, 29-44, 46-60, 62-64, 66-72
  • Terminal/Tray: 33467-0005/23
  • Core/Insulation Crimp: Pins 1-9, 14-25, 27, 29-44, 46-60, 62-64, 66-72 - J/J
  • Core/Insulation Crimp: Pins 11, 12 - K/K
  • Release Tool/Test Probe: J-38125-213/J-35616-64B (L-BU)
  • Pins: 13, 28, 45, 65
  • Terminal/Tray: 33467-0003/23
  • Core/Insulation Crimp: H/H
  • Release Tool/Test Probe: J-38125-213/J-35616-64B (L-BU)
  • Pin: 73
  • Terminal/Tray: 7116-4152-02/9
  • Core/Insulation Crimp: 2/5
  • Release Tool/Test Probe: 12094430/J-35616-35 (VT)
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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.

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