P26EB code meaning
Alternative Fuel Control Module System Voltage
Powertrain system Generic code P26xx codes Check engine light
What P26EB means
On bi-fuel engines a separate alternative fuel control module often runs the gas side. In Ford's bi-fuel CNG documentation of 2002 it contains drivers for both injector sets, switches the fuel relays, picks the active fuel from the selector switch and shuts the tank valve when gas pressure falls below 517 kPa. In Roush CleanTech's propane systems for Ford trucks a smart relay module takes on that role and talks to the PCM over CAN. P26EB says the supply voltage measured by or at this module is outside its permitted window, from a weak feed, a bad ground or a charging fault. No manufacturer documents P26EB publicly. CARB requires an approved monitoring plan for alternate-fuel vehicles. The vehicle will usually refuse or drop gas mode and continue on gasoline.
P26EB at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P26EB
- Gas mode not available or vehicle switches back to gasoline
- Fuel mode indicator flashes or shows a fault
- Warning light on
Common causes of P26EB
- Most likelyLoose, corroded or undersized power or ground connection at the gas control module
- PossibleFaulty fuse, relay or feed circuit of the gas system
- PossibleWeak battery or alternator voltage outside the normal range
- Less likelyInternal fault in the alternative fuel control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Alt fuel control moduleCharging system
What each part of P26EB means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 6 | Area: computer (engine control module) and output circuits. |
| EB | The exact fault in that area. |
What to do next
- Note P26EB and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P26EB
What does P26EB mean?
P26EB means "Alternative Fuel Control Module System Voltage". On bi-fuel engines a separate alternative fuel control module often runs the gas side. It is a generic code, so it means the same on every make.
Is it safe to drive with P26EB?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P26EB fail an emissions test?
Yes, it can. P26EB is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P26EB to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P26EB clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.