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GTECH Calibration
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P1801

Performance Selector Switch Failure.

  • GM
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
01
FaultThe specific fault in that area

What it means

On GM vehicles, P1801 means the control unit has detected a fault in the performance selector switch circuit, the driver-operated switch that chooses between transmission shift modes such as normal and performance or economy. The control unit sets the code when the switch signal is missing, out of range, or does not make sense for the selected mode or other inputs. The exact switch location, circuit design and shift modes depend on the model and year.

Symptoms

  • Malfunction indicator lamp or transmission warning lamp on
  • Performance, power or economy mode selector has no effect
  • Transmission stuck in one shift pattern
  • Harsh, late or unexpected gear changes
  • Performance mode indicator lamp not lighting or flickering

Possible causes

  • Faulty performance selector switch (worn or contaminated contacts)likely
  • Damaged wiring, chafing or corrosion in the switch circuitlikely
  • Loose, corroded or pushed-out pins at the switch or control unit connectorlikely
  • Short to earth or to voltage in the switch signal circuitpossible
  • Blown fuse or poor power or earth supply to the switch circuitpossible
  • Fault inside the transmission or powertrain control unitrare

How to diagnose

  1. Read all stored and pending codes and note freeze frame data, then check for related transmission or electrical codes
  2. Operate the selector switch through all positions and watch the scan data to see whether the control unit sees the state change
  3. Inspect the switch, wiring and connectors for water ingress, corrosion, chafing or bent pins
  4. Check the relevant fuses and the power and earth supply to the switch against the model wiring diagram
  5. Measure switch resistance or continuity in each position and compare with the manufacturer specification
  6. Test the signal circuit for open circuit, short to earth and short to voltage, with the connector unplugged
  7. Check for any applicable service bulletins or calibration updates for your model before condemning the control unit

How to fix

  • Replace the performance selector switch if it fails the resistance or continuity test
  • Repair or replace damaged wiring and terminals in the switch circuit
  • Clean, secure or re-pin faulty connectors and treat any corrosion source
  • Replace blown fuses only after finding and fixing the cause of the overload
  • Replace or reprogram the control unit only when the circuit tests good and the unit is confirmed faulty, or an updated calibration is a known fix

Can I keep driving?

Low severity

The car can usually be driven as the fault tends to affect only shift mode selection, but book it in soon. If shifts become harsh, erratic or the transmission goes into limp mode, have it checked sooner.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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