2007 Chevrolet Uplander Base, 3.9 WFACTORY OEM SERVICE PROCEDURE

Engine Control Module (ECM) Connector End View C2

Fig 1: ECM C2 Connector End View
GM1335545Courtesy of GENERAL MOTORS CORP.
Connector Part Information

Connector Part Information 
  • OEM: 34566-0103
  • Service: See Catalog
  • Description: 73-Way F MX123 Series Sealed (BK)
Terminal Part Information 
  • Pins: 1, 10, 14, 17, 23-24, 26-27, 33, 35, 39-40, 42-43, 46, 59-60, 62-63, 67
  • Terminal/Tray: 33467-0003/23
  • Core/Insulation Crimp: H/H
  • Release Tool/Test Probe: J-38125-213/J-35616-64A (L-BU)
  • Pins: 2-9, 11-13, 29, 32, 44, 48-49, 52, 64, 66, 68- 69, 71-72
  • Terminal/Tray: 33467-0005/23
  • Core/Insulation Crimp: Pins 2-5: K/K
  • Core/Insulation Crimp: Pins 6-9, 11-13, 29, 32, 44, 48-49, 52, 64, 66, 68-69, 71-72: J/J
  • Release Tool/Test Probe: J-38125-213/J-35616-64A (L-BU)
  • Pin: 73
  • Terminal/Tray: 7116-4152-02/9
  • Core/Insulation Crimp: 2/5
  • Release Tool/Test Probe: 12094430/J-35616-4A (PU)
Connector Terminal Identification

Pin Wire Color Circuit No. Function
1 PU 2121 IC 1 Control
2 TN/WH 3111 HO2S Low Signal - Sensor 1
3 PU/WH 3110 HO2S High Signal - Sensor 1
4 PU 3120 HO2S High Signal - Sensor 2
5 GY 3122 HO2S Low Signal - Sensor 2
6 L-BU 1876 Knock Sensor 2 Signal
7 GY 2303 Low Reference
8 D-BU 496 Knock Sensor 1 Signal
9 GY 1716 Low Reference
10 BK/WH 1251 Ground
11 YE 581 TAC Motor Control - 1
12 BN 582 TAC Motor Control - 2
13 PK/BK 5290 Ignition 1 Voltage
14 BN 2198 Camshaft Position Actuator Solenoid High Control
15-16 - - Not Used
17 OG/WH 2122 IC 2 Control
18-22 - - Not Used
23 TN 407 Low Reference
24 TN 808 Low Reference
25 - - Not Used
26 BK/WH 1251 Ground
27 YE/BK 1868 Low Reference
28 - - Not Used
29 TN 2752 Low Reference
30-31 - - Not Used
32 L-BU/BK 844 Fuel Injector 4 Control
33 L-BU 2123 IC 3 Control
34 - - Not Used
35 YE 2174 Low Reference
36-38 - - Not Used
39 D-BU 6259 5-Volt Reference
40 GY 605 5-Volt Reference
41 - - Not Used
42 TN 2760 Low Reference
43 L-GN 1867 5-Volt Reference
44 GY 2701 5-Volt Reference
45 - - Not Used
46 TN 2199 Low Reference
47 - - Not Used
48 L-GN/BK 1745 Fuel Injector 2 Control
49 YE/BK 846 Fuel Injector 6 Control
50-51 - - Not Used
52 TN/WH 845 Fuel Injector 5 Control
53-58 - - Not Used
59 BN/WH 633 CMP Sensor Signal
60 TN/WH 331 Oil Pressure Sensor Signal
61 - - Not Used
62 TN 472 IAT Sensor Signal
63 L-BU/WH 1800 CKP Sensor Signal
64 D-GN 485 TP Sensor 1 Signal
65 - - Not Used
66 PU 486 TP Sensor 2 Signal
67 YE 492 MAF Sensor Signal
68 GY/WH 3113 HO2S Heater Low Control - Sensor 1
69 TN/WH 3121 HO2S Heater Low Control - Sensor 2
70 - - Not Used
71 PK/BK 1746 Fuel Injector 3 Control
72 TN 1744 Fuel Injector 1 Control
73 BK/WH 451 Ground
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.

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