Fault code P0624 is called “Fuel Cap Lamp Control Circuit Malfunction” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0624
OBD-II fault code P0624 is a generic fault code that is defined as “Control circuit malfunction of fuel filler cap check lamp”. Directly indicates the specific location where you should look for the cause of the error.
The fuel filler cap lamp is located in the instrument panel. Its primary function is to alert the driver of an open or missing fuel cap.
The operation of the fuel light is controlled by the PCM using inputs from the fuel tank pressure switch and other sensors. This allows the control module to determine if the fuel cap is properly installed in the filler neck.
If the PCM determines that the cap is loose or missing, the fuel filler cap light should come on. The control module normally monitors the continuity of the fuel filler cap lamp control circuit while the engine is running.
Each time the ignition is turned on and voltage is applied to the PCM, several self-tests of the controller are performed. In addition to performing internal controller self-tests, the Controller Area Network (CAN) is used to compare signals from each individual module. This is done to make sure that the different controllers are communicating properly.
If a problem is detected while monitoring the fuel filler cap lamp control circuit, code P0624 will be stored and the malfunction indicator lamp (MIL) may illuminate. Depending on the perceived severity of the fault, it may take several failure cycles for the MIL to illuminate.
Symptoms of vehicle malfunctions
The main signal that an error P0624 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will light up (the code will be memorized as a fault).
- Other related fault codes may also be present.
- Increased fuel consumption.
- Deactivation of the exhaust evaporation system.
Stored code P0624 is not considered serious, but it is better to eliminate it at the first opportunity. Because a loose or missing fuel cap can lead to fuel contamination as well as emission of harmful fumes into the atmosphere.
Factors that can cause this error code
The error code P0624 can mean that one or more of the following problems have occurred:
- Opened or shorted fuel filler cap lamp control circuit.
- Faulty, loose or missing fuel cap.
- Faulty, loose or missing fuel filler cap lamp control circuit.
- Sometimes a faulty PCM module or programming error is the cause.
How to fix or reset OBD-2 code P0624
Some suggested steps for troubleshooting and fix the error code P0624:
- Read all stored data and error codes with an OBD-II scan tool. To find out when and under what circumstances fault P0624 appeared.
- Clear the error codes from the computer memory and test-drive the vehicle to see if the fault appears again.
- If the error code appears again, visually inspect the electrical wires and control module connector.
- Take out and check the fuel filler cap indicator light.
- Visually inspect the fuel filler cap or lack thereof.
- If there are no defects, check the PCM itself and its program part.
Diagnose and repair of problems
When fault code P0624 occurs, other errors may sometimes be present as well. Associated codes usually refer to abnormal system voltages (high or low). And also to performance range mismatch codes, which may refer to different sensors.
If there are no additional codes, the first thing to do is to check if the fuel filler cap is in place. If present, check that it is properly installed and tightly closed.
Checking the wiring
The next step is to visually inspect all wiring associated with the fuel cap indicator light. If necessary, repair or replace to ensure effective load transfer.
If no visible signs of shorts or other damage are found, use a voltmeter to check resistance and ground. Replace if necessary to ensure that all electrical values are within the limits specified by the manufacturer.
Also locate any fuses that are in any way connected to the fuel filler cap warning light. After checking, replace any damaged or suspect fuses.
You can also measure the system voltage, it should be between 14.2 and 14.8 volts. Allow the vehicle to run at least one full drive cycle before rescanning the system. Most likely there will be no P0624 fault, but sometimes additional clearing with the scan tool is necessary.
On which vehicles does this problem occur most frequently
Fault code P0624 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Ford
- Hyundai (Accent)
- Kia (Rio)
Fault code P0624 can sometimes be found with other errors. The most common are the following: P0621, P0623.
