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P1837

Kick-Down Switch Failed Short.

  • GM
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
8
AreaTransmission
37
FaultThe specific fault in that area

What it means

P1837 on GM vehicles means the Kick-Down Switch has failed short. The kick-down switch tells the transmission control module when the accelerator is pressed fully down so it can command a forced downshift. The control module has seen the switch signal shorted or stuck in the 'pressed' state when it should not be, or at an implausible time, so it has set the fault.

Symptoms

  • Gearbox downshifts unexpectedly or hangs in a lower gear
  • No kick-down or inconsistent kick-down when the pedal is floored
  • Harsh or poorly timed shifts
  • Poor fuel economy from the transmission staying in lower gears
  • Check engine or transmission warning light on
  • Transmission may default to a fixed shift strategy (limp mode)

Possible causes

  • Kick-down switch stuck or internally shortedlikely
  • Wiring in the kick-down switch circuit shorted to ground or to voltagelikely
  • Corroded, damaged or loose connector at the switch or control modulepossible
  • Accelerator pedal or throttle linkage out of adjustment, holding the switch pressedpossible
  • Faulty transmission control module or powertrain control modulerare
  • Water ingress or chafed harness in the switch circuitrare

How to diagnose

  1. Read all stored codes and freeze frame data, noting any related throttle or pedal position codes
  2. Check the live data for the kick-down switch state with the pedal released, part pressed and fully pressed
  3. Inspect the switch, its mounting and the pedal or linkage to see whether it is jammed or misadjusted
  4. Inspect the harness and connectors at the switch and control module for chafing, corrosion, water and bent pins
  5. Check the switch circuit for short to ground and short to voltage using the wiring diagram for the specific model
  6. Test the switch for correct open and closed behaviour with a multimeter, following the manufacturer's procedure
  7. Check for any available updated software for the control module, as applicable to the model
  8. Clear the code and road test to confirm the fault does not return

How to fix

  • Replace the kick-down switch if it is stuck or faulty
  • Repair or replace shorted or damaged wiring and secure the harness
  • Clean or replace corroded connectors and terminals
  • Adjust or repair the pedal or linkage so the switch is not held pressed
  • Replace or reprogram the control module only after the wiring and switch are proven good

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but shifts may be wrong and the gearbox could stay in limp mode. Get it checked soon to avoid unnecessary transmission wear and poor economy.

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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