What Does P0618 Mean?
The Alternative Fuel Control Module has detected a Keep Alive Memory (KAM) error, meaning the module cannot retain learned adaptive values when the vehicle is turned off. This affects vehicles equipped with alternative fuel systems such as CNG, LPG, or flex-fuel. The driver may notice poor cold starts, rough idle after the vehicle has been sitting, or reduced fuel economy as the module must re-learn parameters each start cycle.
Common Causes
35%
Faulty alternative fuel control module with internal KAM failure
25%
Corroded or loose battery connections causing intermittent power loss to module
20%
Damaged wiring or connectors in the alternative fuel module power supply circuit
15%
Low or dead vehicle battery unable to maintain KAM voltage
5%
PCM software issue requiring reflash or update
Diagnostic Steps
1
Check battery voltage with a multimeter — should read 12.4V+ with engine off and 13.5–14.7V with engine running. Load test the battery to ensure it holds charge.
2
Inspect the alternative fuel control module connector for corrosion, bent pins, moisture intrusion, or loose fit. Verify the module has clean, tight ground connections.
3
Using the scan tool, monitor the alternative fuel module power supply PIDs. Verify constant 12V power on the KAM circuit with the ignition off.
4
Check for any aftermarket accessories or parasitic draws that may be draining the KAM circuit. Measure parasitic draw — should be under 50mA after modules go to sleep.
5
If wiring and power supply check out, attempt a module reflash with the latest calibration. If the code returns, replace the alternative fuel control module.
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The Alternative Fuel Control Module has detected a Keep Alive Memory (KAM) error, meaning the module cannot retain learned adaptive values when the vehicle is turned off. This affects vehicles equipped with alternative fuel systems such as CNG, LPG, or flex-fuel. The driver may notice poor cold star...
The most common cause of P0618 (Alternative Fuel Control Module KAM Error) is: Faulty alternative fuel control module with internal KAM failure
Typical repair costs for P0618 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Generally safe to continue driving in the short term, but the vehicle may run poorly on alternative fuel until the module re-learns its parameters each start. Fuel economy will be reduced. Have it diagnosed at your convenience to prevent long-term drivability issues.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0618 to identify the root cause.
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Quick Info
Category
Powertrain
System
Alternative Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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