P027B code meaning
Fuel Pump Module B Control Circuit Range/Performance
Powertrain system Generic code P02xx codes Check engine light
What P027B means
On demand-controlled fuel systems the engine module does not drive the pump itself but sends a pump control module the desired pump output on a separate control line, usually as a duty cycle; the module reports back on a monitor line or via CAN. Module B is a second pump module, for example on dual-tank commercial vehicles. P027B means pump module B receives an invalid command or its feedback does not match. Ford's module signals this with a 20 % (±4 %) duty cycle on its monitor line, checked continuously at 11–16 V over 2–5 s; on Ford commercial vehicles the module B monitor line runs via the smart relay module and CAN to the engine module. Whether the warning light comes on depends on the vehicle.
P027B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor1 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P027B
- Check engine light (vehicle-dependent)
- Fuel shortage when running from the second tank
- Surging, lack of power
Common causes of P027B
- Most likelyContact resistance or corrosion in the control or monitor line to module B
- PossiblePump control module B faulty
- PossibleGround problems
- Less likelyRelay module or CAN forwarding disturbed (Ford commercial vehicles)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Fuel pump control module bFuel pump control wiringEngine control module
What each part of P027B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2 | Area: fuel and air metering (injector circuit). |
| 7B | The exact fault in that area. |
What to do next
- Note P027B 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 P027B
What does P027B mean?
P027B means "Fuel Pump Module B Control Circuit Range/Performance". On demand-controlled fuel systems the engine module does not drive the pump itself but sends a pump control module the desired pump output on a separate control line, usually as a duty cycle; the module reports back on a monitor line or via CAN. It is a generic code, so it means the same on every make.
Is it safe to drive with P027B?
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 P027B fail an emissions test?
Yes, it can. P027B 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 P027B to fix?
Difficulty: medium. A typical repair takes 1 to 3 hours of work. This is a job for a workshop.
Will P027B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.