P0590 code meaning
Cruise Control Multi-Function Input B Circuit Stuck
What P0590 means
Cruise control buttons form a resistor ladder on one or two signal lines, each button giving its own voltage window. FCA uses two lines with offset windows – signal 1 is input A, signal 2 input B – and both must report the same button; GM evaluates the ratio to the reference. Any fault locks out cruise control; CARB treats this as emission-neutral, and GM and Ford set these codes without warning lamp. P0590 means input B reports a pressed button permanently – a button stuck or a voltage hanging in one window. No manufacturer document available to us uses P0590; FCA reports a stuck button with its own code P1593 or with P0585, and GM has no stuck code for input B. Counterpart of P0578 for input A.
P0590 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0590
- Cruise control cannot be engaged, button noticeably sticking
- Cruise control locked out
- No check engine light
Common causes of P0590
- Most likelyButton stuck mechanically (trim, dirt, spilled drink)
- PossibleShort in the button block's resistor ladder
- PossibleMoisture or corrosion in the switch
- Less likelyModule
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cruise control switchClockspringSwitch wiringBody control module
What each part of P0590 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 90 | The exact fault in that area. |
What to do next
- Note P0590 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0590
What does P0590 mean?
P0590 means "Cruise Control Multi-Function Input B Circuit Stuck". Cruise control buttons form a resistor ladder on one or two signal lines, each button giving its own voltage window. It is a generic code, so it means the same on every make.
Is it safe to drive with P0590?
P0590 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0590 fail an emissions test?
P0590 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P0590 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. This is a job for a workshop.
Will P0590 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.