Codes 37/38, TCC Brake Switch On/Off: Notes

1993 Chevrolet Sportvan G30, Van Passenger, 7.4 NSECTION Notes
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The normally closed brake switch supplies battery voltage to the PCM. Signal voltage will drop to zero volts when brake pedal is applied.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. Checks if voltage is available at brake switch.
  2. Checks brake switch function.
  3. Checks circuit from brake switch to PCM.
RENDER: 1.0x

NO RELATED

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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.