What Does P0595 Mean?
The cruise control servo control circuit is reporting a low voltage condition. The PCM detects that the servo control signal or power circuit is being shorted to ground, or the servo is drawing excessive current. This can cause the cruise control servo to be permanently energized or to not respond to control commands properly.
Common Causes
35%
Short to ground in the servo control wire harness
25%
Cruise control servo motor with internal short to ground
20%
Water intrusion or corrosion in the servo connector
12%
Damaged wire insulation where the servo harness contacts vehicle body
8%
PCM driver circuit pulling the control line low internally
Diagnostic Steps
1
Disconnect the cruise control servo connector and check if the low circuit condition clears — if the voltage returns to normal at the PCM, the fault is in the servo or its pigtail.
2
Measure the servo motor resistance — typical is 30-60 ohms; a very low reading indicates an internal short.
3
With the servo disconnected, check the control wire for resistance to ground — it should read OL; any measurable resistance indicates a harness short.
4
Inspect the servo connector for water intrusion — cruise servos on the firewall are exposed to engine bay splash and road spray that can corrode terminals.
5
Trace the wiring harness from the servo to the module, checking for chafed insulation where the harness passes through the firewall grommet or near sharp metal edges.
Estimated Repair Cost
$120 - $550
Parts + labor, varies by vehicle and location
The cruise control servo control circuit is reporting a low voltage condition. The PCM detects that the servo control signal or power circuit is being shorted to ground, or the servo is drawing excessive current. This can cause the cruise control servo to be permanently energized or to not respond t...
The most common cause of P0595 (Cruise Control Servo Control Circuit Low) is: Short to ground in the servo control wire harness
Typical repair costs for P0595 range from $120 to $550, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to drive, but use caution. If the servo is shorted and energized, it could theoretically apply some throttle — however, modern PCMs disable the cruise system entirely when this fault is detected. Stepping on the brake will always override the cruise. Normal accelerator operation is unaffected.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0595 to identify the root cause.
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Quick Info
Category
Powertrain
System
Cruise Control / Speed Control
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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