P0618: Alternative Fuel Control Module KAM Error

What it means

The alternative fuel control module has a keep-alive memory (KAM) error. The code alone does not establish that calibration values are corrupt or that adaptive learning was reset.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The alternative fuel control module uses keep-alive memory (KAM) to retain information while the vehicle is off. P0618 means the module has detected a KAM error; the code alone does not show which contents were affected or whether learning was reset.

Common causes

Most likely first.

1. KAM contents corrupted
2. Module software outdated, reflash may resolve
3. Supply voltage outside specification

Symptoms

• Check engine light on
• Possible limp mode or no-start
• Multiple follow-up faults across modules
• Reset/relearn may be needed after repair

How to diagnose it

1. Record freeze-frame data and scan all modules for related voltage, communication, or alternative-fuel faults before clearing anything.
2. Check the vehicle battery and charging system for signs of low or unstable supply voltage linked to the event.
3. Inspect the alternative fuel control module's power, ground, connectors, and harness for loose, corroded, or damaged connections.
4. Use the scan tool and the manufacturer's procedure to determine whether the KAM fault returns after a key cycle.
5. Check for applicable module software updates and follow the manufacturer's instructions for any reflash or relearn.

Common fixes

• Repair loose, corroded, or damaged module power and ground connections.
• Correct a battery or charging-system problem causing supply voltage outside specification.
• Reflash the alternative fuel control module if an applicable update is specified.
• Replace the module if its KAM fault persists and testing confirms an internal failure.

Can I keep driving?

If the vehicle starts and runs normally, limit driving until the fault is checked because alternative-fuel control may be affected. Do not drive if it stalls, will not start reliably, or enters a reduced-power mode.