OBD Guide
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P18C3

Internal Mode Switch 'S' Circuit Stuck On Invalid Voltage Range

P18C3 is an OBD-II diagnostic trouble code meaning: Internal Mode Switch 'S' Circuit Stuck On Invalid Voltage Range. Common causes: malfunction of internal mode switch 's', open or short circuit in switch circuit. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Incorrect transmission mode detection
  • Check Engine light comes on
  • Gear shifting problems
  • The gearbox may go into emergency mode

Causes

  • Malfunction of internal mode switch 'S'
  • Open or short circuit in switch circuit
  • Poor contact in connectors
  • Transmission control module (TCM) malfunction

How to Fix

  1. Check the integrity of the wiring and connectors in the switch circuit
  2. Check voltage at mode switch 'S'
  3. Replace the faulty mode switch if necessary
  4. Check and, if necessary, replace the transmission control module (TCM)

Related codes

P18C0P18C1P18C2

FAQ

What does the P18C3 code mean?

P18C3 is an OBD-II diagnostic trouble code that indicates: Internal Mode Switch 'S' Circuit Stuck On Invalid Voltage Range

What causes a P18C3 error code?

The most common causes of P18C3 include: Malfunction of internal mode switch 'S'; Open or short circuit in switch circuit; Poor contact in connectors; Transmission control module (TCM) malfunction.

How do I fix a P18C3 diagnostic trouble code?

To fix P18C3: Check the integrity of the wiring and connectors in the switch circuit. Check voltage at mode switch 'S'. Replace the faulty mode switch if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P18C3?

Limited driving only, diagnose soon

How much does it cost to fix P18C3?

The estimated repair cost for P18C3 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat