Powertrain, generic · Computer and auxiliary outputs

P0618 Alternative Fuel Control Module KAM Error

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

CARB treats gas-fuelled vehicles (CNG, LPG, also the gas mode of bi-fuel cars) like petrol cars up to model year 2018 and under an approved manufacturer plan afterwards. P0618 is meant for vehicles with a separate control module for the alternative fuel: it reports an error in that module's keep alive memory, which holds learned values while the ignition is off and loses them when power is cut – the gas counterpart of P0603. No manufacturer was found that uses P0618 this way; Roush's Ford propane conversions, for example, report a failed gas module as U0108. One Chrysler bulletin lists 'P0618' with the title of P061B – apparently a typo, not a second meaning. Expect lost adaptations; bi-fuel cars may switch to petrol. Check supply, fuse and ground of the gas module first.

Likely causes

Power interruption at the gas module (battery disconnected, fuse, loose contact)
Poor supply, ground or corrosion at the module (underbody mounting)
Software or programming fault of the gas module
Internal memory defect

Symptoms

  • Check engine or gas system warning light
  • Switch to petrol, gas mode blocked (bi-fuel)
  • Rough idle until values are relearned
  • Often no symptoms

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–800
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

alternative fuel control modulemodule power supply

Related codes

P0619P0603P0604P0605U0108

References: law.cornell.edu, roushcleantech.com.