2006 Cadillac STS VFACTORY OEM SERVICE PROCEDURE

Engine Control Module (ECM) C1

Fig 1: Powertrain Control Module (PCM) C1 & C3 Connector End View
GM1228485Courtesy of GENERAL MOTORS CORP.
Engine Control Module Connector End Views

Connector Part Information 
  • OEM: 34576-3103
  • Service: 88988373
  • Description: 56-Way F (BU)
Terminal Part Information 
  • Pins: 7, 18, 34, 39, 40, 44, 45, 53, 54, 56
  • Terminal/Tray: 33467-0003/23
  • Core/Insulation Crimp: H/H
  • Release Tool/Test Probe: J-38125-213/J-35616-64B (L-BU)
  • Pins: 9, 12, 13, 20, 33, 35, 36, 37, 46, 47, 48, 49, 19, 55
  • Terminal/Tray: 33467-0005/23
  • Core/Insulation Crimp: Pins 9, 12, 13, 20, 33, 35, 36, 37, 46, 47, 48, 49 - J/J
  • Core/Insulation Crimp: Pins 19, 55 - K/K
  • Release Tool/Test Probe: J-38125-213/J-35616-64B (L-BU)
Engine Control Module (ECM) C1

Pin Wire Color Circuit No. Function
1-6 - - Not Used
7 WH 17 Stop Lamp Switch Signal
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 (Primary)
14-17 - - Not Used
18 YE/BK 5728 ECM/TCM Serial Data Wake Up
19 PK 239 Run/Crank Ignition 1 Voltage
20 RD/WH 1440 Battery Positive Voltage
21-32 - - Not Used
33 WH/BK 1164 Accelerator Pedal Position 5-Volt Reference (1)
34 GY 2709 5-Volt Reference
35 TN 1274 5-Volt Reference
36 BN 1271 Low Reference
37 PU 1272 Low Reference
38 - - Not Used
39 BN 818 Vehicle Speed Signal
40 BN 5069 Powertrain Relay Control
41-43 - - Not Used
44 D-BU 1936 Fuel Level Sensor Signal (Secondary)
45 L-BU 1937 Secondary Fuel Level Sensor Signal
46 BN 7123 Super Charger Inlet Air Pressure Sensor Signal
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 D-BU 473 High Speed Cooling Fan Relay Control
55 WH 1310 EVAP Canister Vent Solenoid Control
56 YE 447 Starter Relay Coil 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.