What Does P1597 Mean?
This code indicates the cruise control (speed control) switch is continuously reading in the low or pressed state. The PCM detects that the cruise switch input remains active when it should not be, which suggests a stuck button, shorted wiring, or a faulty clockspring assembly. Cruise control will be disabled because the PCM cannot differentiate intentional commands from the stuck signal.
Common Causes
30%
Stuck or physically jammed cruise control switch on the steering wheel
25%
Short to ground in the cruise control switch signal wiring
20%
Faulty clockspring (steering column spiral cable) with internal short
15%
Water or debris contamination inside the steering wheel switch assembly
10%
Aftermarket steering wheel or switch installation with incorrect wiring
Diagnostic Steps
1
Physically inspect the cruise control buttons on the steering wheel; press each one and verify they return freely without sticking.
2
Monitor the cruise control switch input signal on live data; it should change states when the button is pressed and released.
3
Disconnect the cruise control switch connector at the clockspring and check if the signal returns to normal—if so, the switch or clockspring is at fault.
4
Measure resistance through the cruise control switch in the released and pressed positions; compare to service manual specifications.
5
If the switch checks out, inspect the wiring from the clockspring to the PCM for shorts to ground.
Estimated Repair Cost
$80 - $400
Parts + labor, varies by vehicle and location
This code indicates the cruise control (speed control) switch is continuously reading in the low or pressed state. The PCM detects that the cruise switch input remains active when it should not be, which suggests a stuck button, shorted wiring, or a faulty clockspring assembly. Cruise control will b...
The most common cause of P1597 (Speed Control Switch Always Low) is: Stuck or physically jammed cruise control switch on the steering wheel
Typical repair costs for P1597 range from $80 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Cruise control will not function, but a stuck switch could theoretically cause unintended cruise engagement if the fault is intermittent. Some vehicles may also illuminate the cruise indicator light continuously.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1597 to identify the root cause.
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Quick Info
Category
Powertrain
System
Cruise Control
Difficulty
Type
Manufacturer
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