Technical Description of OBD-II Trouble Code
The Cruise Control Multi-Function Input B Circuit is registering a low signal.
What does that mean?
This is a standard diagnostic trouble code (DTC) for powertrain issues in OBD-II vehicles. This code can apply to various vehicle brands such as Mazda, Alfa Romeo, Ford, Land Rover, Jeep, Dodge, Chrysler, Chevy, Nissan, and more. The specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
Cruise control was designed for our convenience. Its main purpose is to maintain a manually set vehicle speed (using steering wheel buttons, multifunction switch on the steering column, etc.)
With cruise control, the driver no longer needs to control the gas pedal. If the vehicle has an automatic transmission (A/T), cruise control can also adjust shift points based on real-time driving conditions.
In this case, it is likely that the multifunction switch on the steering column is causing the code. However, the location of the switch can vary significantly between manufacturers, so further research is necessary. Start by checking the cruise control button to narrow down the possible locations. The code refers to a specific input circuit within the cruise control system. Consult the service manual for guidance on which wire/circuit to focus on.
When there is a fault in the cruise control multi-function “B” input circuit, the engine control module (ECM) will illuminate the instrument cluster with the P0592 code and related codes (P0589, P0590, P0591, P0592, and P0593).
The letter “B” in this context could be used to distinguish a connector, wire, or circuit group. The manufacturer’s specifications are the best resource for understanding this.
The P0592 code is set by the ECM when the electrical value of the “B” cruise control multi-function input circuit is unexpectedly low.
A cruise control stalk:
What is the severity of this DTC?
This DTC is generally of low severity for cruise control faults, although there can be exceptions. In most cases, this fault should not cause serious concern. However, electrical issues tend to worsen over time. The cost of fixing this fault is usually moderate. It is important to shop around for the best prices and obtain multiple quotes and diagnosing strategies. Regular vehicle maintenance is always recommended.
What are some of the symptoms of the code?
Symptoms of a P0592 trouble code may include:
What are some of the common causes of the code?
Common causes of the P0592 code may include:
What are some P0592 troubleshooting steps?
Basic Step #1
Inspect the Multi-function/Cruise control switch for any contamination. Plastic buttons/switches can easily become dirty, greasy, or sticky, leading to malfunctions or abnormal operation. Ensure that the switch operates smoothly. Address any problems immediately. If your scan tool/OBD reader allows, observe the electronic operation of the switch through DATA STREAM mode.
TIP: Avoid spraying cleaning solutions directly onto the button. Use a lightly dampened clean rag with water, soap & water, or dash cleaner to remove debris from the switch’s crevices. An air-powered blow gun can help remove debris without causing further issues.
Basic Step #2
To access the connectors and harnesses involved in the cruise control/multi-function switch input circuit, you may need to remove some dash plastic/shrouds. Be careful when working with plastic. Comfortable room temperatures can make dash/interior plastic disassembly/assembly easier.
If you can easily access the connector, follow specific troubleshooting steps provided in your service manual. Switch testing will likely involve recording electrical values using a multimeter. This may include operating the switch while recording or static testing. Refer to the specific make and model’s service manual for a diagnostic flow chart.
Basic Step #3
A problem with the ECM is usually the last resort in diagnosis. Given the potential cost of electronic repairs, it is best to leave this to professionals.
