Faulty or misadjusted kick-down switch, or worn throttle pedal assembly; Damaged wiring, chafed loom or open or short circuit in the kick-down switch circuit; Corroded, loose or water-contaminated connector at the switch or control module; Throttle position signal fault disagreeing with the kick-down switch signal; Poor power or earth supply to the switch circuit; Fault inside the transmission control module or engine control module.

P1835

Kick-Down Switch.

GMC
Powertrain
Manufacturer code
Medium severity

How this code is built

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

What it means

P1835 on a GMC vehicle relates to the kick-down switch circuit, the switch that tells the transmission control module when the throttle pedal has been pushed to or near full travel so it can command a downshift. The control module has seen a signal from this circuit that is implausible, stuck, open or shorted compared with throttle position and driving conditions. The exact switch location and how the fault is judged depend on the model, engine and transmission fitted.

Symptoms

Transmission will not downshift when the throttle is pressed hard
Unexpected or constant kick-down, with the gearbox hanging on to lower gears
Harsh, late or erratic shifts
Poor acceleration when overtaking
Check engine or transmission warning light on
Transmission may default to a fixed gear or limp mode on some models

Possible causes

Faulty or misadjusted kick-down switch, or worn throttle pedal assemblylikely
Damaged wiring, chafed loom or open or short circuit in the kick-down switch circuitlikely
Corroded, loose or water-contaminated connector at the switch or control modulelikely
Throttle position signal fault disagreeing with the kick-down switch signalpossible
Poor power or earth supply to the switch circuitpossible
Fault inside the transmission control module or engine control modulerare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting any throttle position or pedal codes
Check for related throttle, pedal or transmission codes and deal with those first as they can cause this one
Inspect the throttle pedal assembly and kick-down switch area for damage, debris, wear or incorrect adjustment
Inspect the wiring and connectors from the switch to the control module for chafing, corrosion, moisture and pushed-out pins
With a scan tool, watch the kick-down switch status and throttle position while pressing the pedal slowly to full travel, and check the switch changes state at the right point
Check the switch and circuit with a multimeter for continuity, short to earth, short to voltage and correct reference voltage, following the wiring diagram for the model
Check supply and earth to the switch circuit under load
Only once the circuit and switch are proven good, consider a fault in the control module and check for any applicable software updates for that model

How to fix

Replace or adjust the kick-down switch or throttle pedal assembly as the model requires
Repair or replace damaged wiring and fix any short or open circuit
Clean, dry and reseat connectors, replacing corroded terminals or connectors
Correct any throttle position sensor or pedal sensor faults found
Repair poor power or earth connections to the circuit
Replace or reprogram the control module only if testing proves it faulty or an updated calibration is a known fix for the model

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but poor downshifting can make overtaking and hill driving less safe. Get it checked soon, especially if the gearbox is shifting harshly or has gone into limp mode.

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