P0577 code meaning
Cruise Control Input Circuit High
What P0577 means
Cruise control buttons are almost always a resistor ladder on one or two signal lines, each button giving its own voltage; the module reading it (GM and Saab from about 2010: the body module; FCA: steering column module or PCM) sends the button state to the engine module over CAN. CARB names cruise control as the example of an emission-neutral diagnosis – it is simply switched off – so GM lists all these codes as type C and Ford as non-MIL: no warning lamp, the engine runs normally. P0577 means the input signal is above its upper limit – an open signal or switch ground (often in the clockspring) or a short to positive. FCA's ladder treats over 4.706 V as circuit high, with about 4.54 V at rest. No manufacturer document available to us uses this code. For line A makers use P0581.
P0577 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0577
- Cruise control inoperative
- Cruise control locked out
- No check engine light, engine runs normally
Common causes of P0577
- Most likelySignal or switch ground open (clockspring)
- PossibleSignal shorted to positive
- Less likelyModule faulty
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 P0577 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. |
| 77 | The exact fault in that area. |
What to do next
- Note P0577 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 P0577
What does P0577 mean?
P0577 means "Cruise Control Input Circuit High". Cruise control buttons are almost always a resistor ladder on one or two signal lines, each button giving its own voltage; the module reading it (GM and Saab from about 2010: the body module; FCA: steering column module or PCM) sends the button state to the engine module over CAN. It is a generic code, so it means the same on every make.
Is it safe to drive with P0577?
P0577 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0577 fail an emissions test?
P0577 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 P0577 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0577 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.