P0619
Alternative Fuel Control Module RAM/ROM Error
Alternative fuel control module
Generic OBD-II
High
What it means
P0619 indicates the Alternative Fuel Control Module has failed an internal RAM or ROM memory check, so the computer that manages the CNG, LPG, or flex-fuel system can't operate reliably. It can cause reduced power, hard starting on the alternative fuel, and emissions problems, and usually points to the module itself or its power supply.
High
Can I keep driving? Often limited — the alternative-fuel system may lose power, run poorly, or be hard to start, so the vehicle may need to run on its backup fuel until repaired.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or poor performance on the alternative fuel
- Hard starting on the alternative-fuel system
- Poor fuel efficiency and emissions-related problems
- Rough idle or misfires while on the alternative fuel
Common causes
Most likely first
- Internal RAM/ROM memory fault in the Alternative Fuel Control ModuleLikely
- Corrupted module software or programmingCommon
- Power or ground supply problems to the moduleCommon
- Damaged wiring or connectors in the module circuitLess often
- Poor electrical connection at the moduleLess often
How to diagnose & fix
Work through it in order
- Check the module's power and ground supplies and battery condition first; unstable voltage can corrupt memory.
- Inspect the module connectors and wiring for damage or corrosion; repair as needed.
- Check for and apply any software update or reflash for the module.
- If the internal memory fault persists, replace the Alternative Fuel Control Module and program it. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0619?+
The alternative-fuel system may be unreliable — expect reduced power or hard starting. Many bi-fuel vehicles can run on their backup fuel, but get the module diagnosed.
Can I just clear P0619?+
A genuine internal memory error will return. Clearing may help if it was a one-time glitch from low voltage, but a repeat means the module or its supply needs attention.
Related codes
Often seen with P0619
Read & clear P0619 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX