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GTECH Calibration
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P1801

Performance Selector Switch Failure.

  • Cadillac
  • 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

P1801 on a Cadillac means the powertrain control module has detected a fault in the performance selector switch circuit. This is the driver-operated switch that chooses between transmission shift modes such as normal and performance. The module set the code because the switch signal was missing, out of range or did not match the expected state.

Symptoms

  • Malfunction indicator lamp on
  • Performance or mode selector button has no effect on shift behaviour
  • Transmission stays in one shift mode regardless of switch position
  • Shifts feel firmer or softer than usual
  • Mode indicator in the cluster does not change

Possible causes

  • Faulty performance selector switch (worn or sticking contacts)likely
  • Damaged, chafed or corroded wiring in the switch circuitlikely
  • Poor connection or corroded terminals at the switch or control module connectorpossible
  • Short to ground, short to voltage or open circuit in the signal or reference wirepossible
  • Moisture or spilled drink contamination in the switch or centre consolepossible
  • Faulty powertrain control module or transmission control modulerare

How to diagnose

  1. Read the stored codes and freeze frame data, and note whether P1801 is current or history and whether other transmission or network codes are present
  2. Operate the selector switch and watch the scan data for the switch state changing; confirm whether the signal responds in every position
  3. Visually inspect the switch, console area and wiring for damage, moisture, corrosion or previous repairs
  4. Check the switch connector and the control module connector for bent, loose or corroded terminals
  5. Check the supply, reference and ground at the switch against the model-specific wiring diagram
  6. Test the switch with a multimeter in each position for correct resistance or continuity as per the manufacturer's specification
  7. Wiggle-test the harness while watching live data to find intermittent faults
  8. Check the wiring for continuity and for shorts to ground or voltage between the switch and the control module

How to fix

  • Replace the performance selector switch if it fails the electrical tests
  • Repair or replace damaged wiring in the switch circuit
  • Clean or replace corroded or loose connector terminals
  • Dry and clean contamination from the switch area and replace any affected parts
  • Replace or reprogram the control module only after the wiring and switch are proven good and the manufacturer's procedure calls for it

Can I keep driving?

Low severity

The car can normally be driven as the fault only affects the shift mode selection, though the transmission may stay in a default mode. Book it in for repair soon, and stop for checks if you notice harsh shifting or other transmission faults.

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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