DTC C1276, DTC P1644 Or DTC P1689: Delivered Torque Signal Malfunction

2001 Chevrolet Venture Base, Van Cargo ExtendedSECTION DTC C1276, DTC P1644 Or DTC P1689: Delivered Torque Signal Malfunction
  1. Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK  under DIAGNOSIS & TESTING. After performing diagnostic system check, go to next step.
  2. Check EBCM and PCM ground. Ensure each ground is clean and torqued properly. Repair as necessary. After repairs, go to step  11 . If grounds are okay, go to next step.
  3. Install scan tool. Start engine. Using scan tool, observe PCM-to-EBTCM delivered parameter in the TCS data list. If scan tool displays 90%, go to next step. If scan tool does not display 90%, problem is intermittent. See INTERMITTENTS & POOR CONNECTIONS  under DIAGNOSIS & TESTING.
  4. Turn ignition off. Disconnect EBCM harness connector. Install Universal Breakout Box (J-39700) using the Cable Adapter (J-39700-99) to EBCM harness connector and EBCM. Disconnect PCM harness connector. Turn ignition on, with engine off. Check voltage from the delivered torque signal circuit to a good ground. If voltage reading is about battery voltage, go to next step. If voltage reading is not about battery voltage, go to step  6 .
  5. Turn ignition off. Disconnect cable adapter from EBCM. Turn ignition on, with engine off. Check delivered torque signal circuit for short to voltage. Repair as necessary. After repairs, go to step  11 . If circuit is okay, go to step  7 .
  6. Turn ignition off. Disconnect cable adapter from EBCM connector. Check delivered torque signal circuit for open, short to ground or high resistance. Repair as necessary. After repairs, go to step  11 . If circuit is okay, go to step  8 .
  7. Check PCM harness connector for poor connections. Repairs as necessary. After repairs, go to step  11 . If connections are okay, go to step  9 .
  8. Check for EBCM harness connector poor connections. Repair as necessary. After repairs, go to step  11 . If connections are okay, go to step  10 .
  9. Replace PCM. Program replacement PCM. After replacing PCM, go to step  11 .
  10. Replace EBCM. After replacing EBCM, go to next step.
  11. Using scan tool, clear DTCs. Recheck for DTCs. If DTC resets, go to step  2 . If DTC does not reset, system is okay.
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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.