P2A32: AFCM Power Relay Control Circuit/Open
What to do
The car will run on petrol. This is usually a relay, a fuse or an earth rather than the module — all cheap, and all worth eliminating before anyone quotes for a control module. A gas installer will find it faster than a general workshop.
What this code means
The alternative fuel control module's power relay control circuit is faulty.
The AFCM is the Alternative Fuel Control Module, and understanding what it does explains most of this range.
It is a second engine computer, added alongside the original one. On nearly every conversion the petrol module is left completely untouched — it goes on calculating injection timing as though the car were running on petrol. The AFCM intercepts the signals going to the petrol injectors, works out how much gas that quantity of petrol corresponds to, and fires the gas injectors instead.
That design is why conversions work at all across hundreds of vehicle types, and it is also why the AFCM has its own power supply, its own relay, and its own fault codes: it is an independent computer that the car's own diagnostics barely know about.
The sense circuit is the part worth understanding. A relay's control circuit proves the module asked for power. The sense circuit is the module reading back whether power actually arrived — and having both is what distinguishes a driver that failed from a relay that failed from a supply that was never there. A control circuit that tests good proves nothing about the contacts.
The relay's control circuit is open — the module cannot energise its own supply.
Likely causes
Start here
- Faulty module power relay · specialist
- Blown fuse or failed supply · easy
- Corroded or loose connector · specialist
Less common
- Corroded earth connection · moderate
- Failed alternative fuel control module · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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