P18BC - Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
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P18BC Possible Causes

  • Faulty Internal Mode Switch
  • Internal Mode Switch harness is open or shorted
  • Internal Mode Switch circuit poor electrical connection

First diagnose P18BC code

    Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

Cost of diagnosing the P18BC code

    Labor: 1.0

    The cost of diagnosing the P18BC code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

P18BC Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P18bc Description

The internal mode switch indicates to the Transmission Control Module (TCM) which gear position the vehicle operator has selected. The internal consists of 5 separate hall effect switches. Each hall effect switch is supplied a 9 V reference circuit and a signal circuit from the TCM. Each signal circuit for each gear selector position will have either a voltage reading of 0.70-0.96 V indicting On or 1.68-2.38 V indicating Off. The voltage values on each internal mode switch circuit will change and are dependent on the position of the gear selector. The state of each internal mode switch A/B/C/P/S signal circuit is displayed on the scan tool.
OBDII Code P18bc - Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range - AutoCodes.com

P18BC More Information

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P18BC Information for specific makes

  • P18BC BUICK Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range
  • P18BC CADILLAC Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range
  • P18BC CHEVROLET Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range
  • P18BC GMC Internal Mode Switch 'C' Circuit Stuck Off Invalid Voltage Range

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