What Does P0590 Mean?
The cruise control multi-function input 'B' circuit is stuck, meaning the PCM detects a constant signal value from this input that does not change when cruise control buttons are pressed or released. This suggests a button is physically stuck, a wire is shorted to a fixed voltage, or the resistor network has failed. The cruise control system will likely be completely disabled as a safety precaution.
Common Causes
35%
Cruise control switch physically stuck in one position due to debris or mechanical failure
25%
Short in the circuit wiring holding the signal at a fixed voltage level
20%
Damaged clockspring creating a constant connection on one circuit path
12%
Contamination (spilled drink, dirt) in the steering wheel switch contacts
8%
Failed resistor in the switch resistor ladder network
Diagnostic Steps
1
Monitor the cruise control input 'B' PID on the scan tool — the signal should change when cruise buttons are pressed and return to a baseline when released; a constant stuck value confirms the code.
2
Remove the steering wheel airbag module (follow proper disable procedures) and inspect the cruise control switches for physical damage, stuck buttons, or contamination.
3
Disconnect the cruise control switch connector at the clockspring and check if the stuck signal clears — if it does, the fault is in the switch or its pigtail.
4
Measure the signal wire voltage with the switch disconnected — it should read the pull-up or pull-down reference voltage, not a mid-range voltage that mimics a pressed button.
5
Check the switch contact resistance values with a DVOM in each button position and verify they match the manufacturer's specifications for the resistor ladder.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The cruise control multi-function input 'B' circuit is stuck, meaning the PCM detects a constant signal value from this input that does not change when cruise control buttons are pressed or released. This suggests a button is physically stuck, a wire is shorted to a fixed voltage, or the resistor ne...
The most common cause of P0590 (Cruise Control Multi-Function Input "B" Circuit Stuck) is: Cruise control switch physically stuck in one position due to debris or mechanical failure
Typical repair costs for P0590 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The cruise control system will be disabled by the PCM due to the stuck input, which is actually a safety measure. There is no risk of unintended acceleration because the PCM disables cruise when it detects an invalid input. Normal driving is unaffected.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0590 to identify the root cause.
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Quick Info
Category
Powertrain
System
Cruise Control / Speed Control
Difficulty
Type
Generic (SAE)
Recommended Tools
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