Circuit/System Testing

2019 Chevrolet Tahoe LS, 4WD, Gas/EthanolSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2018 Chevrolet Sonic. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:

Diagnose any Engine Control Module DTCs before performing this diagnostic.

  1. Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
  2. Engine running at 600 RPM,
  3. Test for 575-800 Hz AC between the signal circuit terminal 23 and ground.
    • If not between 575-800 Hz ACΒ 
    1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module. Ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Ignition OFF.
    4. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    5. Test for less than 2 Ξ© in the signal circuit end to end.
      • If 2 Ξ© or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ξ©, replace the K20 Engine Control Module.
    • Go to next step: If between 575-800 Hz ACΒ 
  4. Test or replace the A11 Radio.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.