P0581 code definition
The P0581 code indicates that the PCM has detected a malfunction in the electrical components of the cruise control multi-function input circuit.
What the P0581 code means
In order to assist the cruise control module in controlling vehicle speed, the PCM monitors the performance of all cruise control components. If the PCM detects that the cruise control multi-function circuit is providing an abnormal voltage reading (as opposed to the manufacturer’s specifications for the current drive conditions), it will store the P0581 code.
What causes the P0581 code?
In most cases, a faulty cruse control switch is the problem behind the P0581 code. This switch can fail due to shorted or open circuitry, particularly in the cruise control buttons if water, liquid, or dirt has been spilled onto the buttons. Other causes may include:
- Open, shorted, or otherwise damaged electrical components, such as wiring, connectors, and harnesses
- Blown fuses, which may indicate a larger issue
What are the symptoms of the P0581 code?
In addition to the illuminated Check Engine lamp, this code is usually accompanied by an inability to use the cruise control. Blown fuses may be a cause or a symptom, depending on the exact nature of the issue causing the P0581 code.
How does a mechanic diagnose the P0581 code?
After verifying the code with an OBD-II scanner, it is important to inspect all electrical components, and perform any repairs that are necessary on the wiring, connectors, or harnesses. Afterwards, clearing the code from the PCM, and performing a retest, will let the technician know if this has resolved the issue. If the code reappears in the PCM, the next step is to replace the cruise control switch. If the code reappears after this repair, the mechanic may need to disconnect the cruise control switch, and manually test the voltage reading to find the source of the problem.
Common mistakes when diagnosing the P0581 code
The most common misdiagnosis with the P0581 code, is replacing components that were or were not faulty, without checking for blown fuses. If a fuse is blown, a replacement part will likely fail again quickly.
How serious is the P0581 code?
While the cruise control may not be usable, but this should not affect any other function of the vehicle; therefore, the P0581 code is only a mild repair issue. However, if a fuse is blown, there may be some other minor electrical issues, such as the inability to use the turn signal, which could cause unsafe driving conditions; in this case, the P0581 code would be considered a more serious repair issue.
What repairs can fix the P0581 code?
There are many ways that a technician can address a P0581 code detection. They include:
- Replacing a faulty cruise control switch
- Replacing damaged cruise control buttons to ensure a replacement switch does not become damaged
- Repairing open, shorted, or otherwise damaged electrical components, such as wiring, connectors, and harnesses
- Replacing blown fuses
Additional comments for consideration regarding the P0581 code
An unresolved P0581 code that is still stored in the PCM means that the vehicle may not be able to pass an emissions test.
Need help with a P0581 code?
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