Technical Description of OBD-II Trouble Code
Error in Alternative Fuel Control Module KAM
What does that signify?
This generic powertrain diagnostic trouble code (DTC) is commonly found in many OBD-II vehicles, including those from Volkswagen VW, Ford, Nissan, and others.
A stored code P0618 indicates a malfunction in the alternative fuel control module (AFCM) detected by the powertrain control module (PCM). The issue specifically occurs in the keep-alive memory (KAM) section of the AFCM/PCM.
The P0618 code is applicable to vehicles that utilize alternative fuels such as natural gas and electricity for propulsion.
In some cases, the AFCM and PCM may be separate modules, but more often they are integrated into a single module. This integration improves controller efficiency and saves space, time, and money for automakers.
KAM enables the PCM and other controllers to retain data even when the ignition is turned off or there is a brief interruption in battery power.
Every time the ignition is turned on and the PCM is powered, multiple self-tests are conducted by the controllers. Along with internal self-tests, the controller area network (CAN) is used to compare signals from each module to ensure proper interaction between the controllers.
If a problem is detected in the AFCM/PCM KAM capacity, a code P0618 is stored and a malfunction indicator lamp (MIL) may illuminate. Depending on the perceived severity of the malfunction, multiple failure cycles may be required for MIL illumination.
Example photo of a fuel pump control module:
What is the severity of this DTC?
Internal control module codes should always be taken seriously. A stored code P0618 could lead to various drivability concerns as valuable controller memory may be lost.
What are some of the symptoms of the code?
Symptoms of a P0618 trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P0618 troubleshooting steps?
Unfortunately, even the most experienced and well-equipped professional technician may find diagnosing a code P0618 to be quite challenging. Reprogramming is also an issue, as without the necessary equipment, it is impossible to replace a defective controller and complete a successful repair.
If AFCM/PCM power supply codes are present, they need to be addressed before attempting to diagnose a P0618.
There are several preliminary tests that can be performed before determining if a controller is defective. A diagnostic scanner, a digital volt/ohmmeter (DVOM), and reliable vehicle information are required.
Connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. It is important to write down this information in case the code is intermittent. After recording the information, clear the codes and test drive the vehicle until the code is reset or the PCM enters readiness mode. If the PCM enters readiness mode, the code is intermittent and will be more difficult to diagnose. The condition that caused the P0618 to be stored may even need to worsen before a diagnosis can be made. If the code is reset, continue with the following preliminary tests.
When diagnosing a P0618, information is crucial. Search for technical service bulletins (TSB) that match the stored code, vehicle (year, make, model, and engine), and exhibited symptoms. The right TSB may provide diagnostic information that can greatly assist in the diagnosis.
Use the vehicle information source to obtain connector face views, connector pin-out charts, component locators, wiring diagrams, and diagnostic flow charts related to the code and vehicle in question.
Use the DVOM to test controller power supply fuses and relays. Replace blown fuses as necessary. Fuses should be tested with the circuit loaded.
If all fuses and relays appear to be functioning properly, visually inspect the wiring and harnesses related to the controller. Also check the chassis and engine ground junctions. Use the vehicle information source to find ground locations for related circuits. Use the DVOM to test ground integrity.
Inspect system controllers for signs of water, heat, or collision damage. Any damaged controller, especially due to water, should be considered defective.
If controller power and ground circuits are intact, suspect a defective controller or a controller programming error. Controller replacement will require reprogramming. In some cases, reprogrammed controllers can be purchased through aftermarket sources. Other vehicles/controllers will require on-board reprogramming that can only be done through a dealership or other qualified source.
