2008 Chevrolet Chevy Express G2500, Van Cargo Extended, 6.0 KFACTORY OEM SERVICE PROCEDURE

Transmission Control Module (TCM) (Gas)

Fig 1: Transmission Control Module (TCM) (Gas) Connector End View
GM1544228Courtesy of GENERAL MOTORS CORP.
Transmission Control Module (TCM) (Gas)

Pin Wire Circuit Function
1 0.5 BN 418 Torque Converter Clutch Pulse Width Modulation (TCC PWM) Solenoid Valve Control
2 0.5 L-GN 1222 Shift Solenoid A Valve Control
3 0.35 BN/WH 6254 ISS Signal (4L60)
0.5 OG/BK 1230 Automatic Transmission Input Speed Sensor (AT ISS) High Signal (4L80)
4 - - Not Used
5 0.5 OG/BK 6399 Replicated TOS Signal
6 0.5 TN 2501 High Speed GMLAN Serial Data Bus (-)
7 0.5 TN/BK 2500 High Speed GMLAN Serial Data Bus (+)
8-10 - - Not Used
11 0.5 D-BU 5985 Accessory Wakeup Serial Data
12-13 - - Not Used
14 0.5 WH 687 3-2 Shift Solenoid Valve Control
15 0.5 TN 2501 High Speed GMLAN Serial Data Bus (-)
16 0.5 L-GN/BK 822 Vehicle Speed Sensor (VSS) Low Signal
17 0.35 L-BU/WH 1229 PC Solenoid Valve Low Control (Sol. A)
18 - - Not Used
19 0.5 TN/BK 2500 High Speed GMLAN Serial Data Bus (+)
20 0.5 YE/BK 1223 Shift Solenoid B Valve Control
21-22 - - Not Used
23 0.35 GY 773 Transmission Range Switch Signal C
24 0.35 PK 1224 Transmission Fluid Pressure Switch Signal A
25 0.5 TN/BK 422 Torque Converter Clutch (TCC) Solenoid Valve Control
26 0.5 D-BU/WH 1231 Automatic Transmission Input Speed Sensor (AT ISS) Low Signal (4L80)
27-28 - - Not Used
29 0.35 TN/WH 771 Transmission Range Switch Signal A
30 0.35 TN 452 Low Reference
31 0.5 PK 2139 Ignition Voltage
32 0.35 RD/WH 1840 Battery Positive Voltage
33 0.35 OG 1226 Transmission Fluid Pressure Switch Signal C
34 - - Not Used
35 0.35 YE/BK 1227 Transmission Fluid Temperature (TFT) Sensor Signal
36 - - Not Used
37 0.5 TN 2501 High Speed GMLAN Serial Data Bus (-)
38 0.5 TN/BK 2500 High Speed GMLAN Serial Data Bus (+)
39 0.35 WH 776 Transmission Range Switch Signal P
40 0.35 OG/BK 1228 PC Solenoid Valve High Control (Sol. A)
41 0.5 PU/WH 821 Vehicle Speed Sensor (VSS) High Signal
42 0.5 L-BU/WH 6311 Torque Converter Clutch (TCC) Brake Signal
43 - - Not Used
44 0.35 D-BU 1225 Transmission Fluid Pressure Switch Signal B
45 0.35 D-BU 6253 Low Reference
46 0.35 YE 772 Transmission Range Switch Signal B
47-48 - - Not Used
49 2 BK/WH 1551 Ground
Connector Part Information 
  • OEM: 15463921
  • Service: 88987979
  • Description: 49-Way F GT 280 Micro-Pack 64 Sealed (BK)
Terminal Part Information 
  • Pins: 1-3, 5-7, 11, 14-17, 19, 20, 23-26, 29, 30-33, 35, 37-42, 44-46
  • Terminal/Tray: 15359541/4
  • Core/Insulation Crimp: M/M
  • Release Tool/Test Probe: 15381651-2/J-35616-64B (L-BU)
  • Pins: 49
  • Terminal/Tray: 15392777/23
  • Core/Insulation Crimp: See Terminal Repair Kit
  • Release Tool/Test Probe: J-38125-553/J-35616-4A (PU)
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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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