Faulty speed control switch or steering wheel switch assembly with an internal short or stuck contact; Worn or damaged clockspring or contact ring in the steering column affecting the switch signal; Signal wire shorted to voltage, or damaged insulation in the switch circuit; Corroded, loose or contaminated connector terminals in the switch circuit; Open circuit on the switch ground or reference return causing a high reading; Faulty control module input circuit.

P1596

Speed Control Switch Always High.

Pontiac
Powertrain
Manufacturer code
Low severity

How this code is built

P: SystemPowertrain
1: Defined byThe manufacturer
5: AreaVehicle speed, idle control and auxiliary inputs
96: FaultThe specific fault in that area

What it means

On Pontiac, P1596 means the speed control (cruise control) switch signal has been seen stuck high. The control unit monitors the voltage on the cruise switch input circuit and sets the code when it reads high when no button is being pressed, or stays high for longer than expected. Cruise control will normally be unavailable while the fault is present.

Symptoms

Cruise control will not engage or set
Cruise control cuts out unexpectedly
Cruise control buttons have no effect
Cruise indicator light not working as expected
Check engine light or service warning on

Possible causes

Faulty speed control switch or steering wheel switch assembly with an internal short or stuck contactlikely
Worn or damaged clockspring or contact ring in the steering column affecting the switch signalpossible
Signal wire shorted to voltage, or damaged insulation in the switch circuitpossible
Corroded, loose or contaminated connector terminals in the switch circuitpossible
Open circuit on the switch ground or reference return causing a high readingpossible
Faulty control module input circuitrare

How to diagnose

Read all stored codes and freeze frame data, noting whether the fault is current or intermittent, then check for related codes
Operate each cruise control button and check whether any feel stuck, sticky or damaged
Inspect the switch, steering column wiring and connectors for damage, moisture or corrosion
Using a scan tool, watch the switch input data while pressing each button and note whether it reads high at rest
Check the switch circuit voltage, reference and ground against the manufacturer wiring diagram, as circuit layout depends on model and year
Wiggle test the harness and clockspring area while watching the live data for changes
Test the circuit wiring for shorts to voltage and for open circuits, with the switch unplugged
Only after the wiring and switch are proven good, consider testing the control module input

How to fix

Replace the speed control switch or switch assembly if it is stuck or faulty
Replace the clockspring or contact ring if it is worn or faulty
Repair any wiring shorted to voltage or open circuit in the switch harness
Clean or replace corroded or damaged connector terminals
Repair or replace the control module only if the circuit and switch are proven good and the fault remains

Can I keep driving?

Low severity

The car is safe to drive normally, but the cruise control will probably not work. Book it in at your convenience, but have the steering column wiring checked if other steering wheel controls or the airbag light are also affected.

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