Powertrain, generic (extended)

P25B1 Fuel Level Sensor B Stuck

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P25B1 points at the second fuel level sender, the one found in the passive half of a saddle tank or in an additional tank. Its reading no longer changes in step with the fuel actually burned. Ford applies the same consumption comparison as for sender A, with mismatch limits between 25 % and 60 % depending on the frozen level, and the 2024 summary maps this fault to P2065 with failure type 2A. A frozen B reading is not always the sender's fault: if the jet pump that pulls fuel across from the passive side stops working, that half really does stay full while the other empties, which looks the same to the module. The averaged gauge value then drifts away from the true content and the range estimate becomes unreliable. Ford's 2014 Boss 302S list gives P25B1 the lamp; GM uses P2066 for a stuck second sender instead.

Likely causes

Float of sender B jammed or resistor track worn
Jet pump or its line no longer drawing fuel from the passive tank half
Blocked or kinked transfer line between the tank chambers

Symptoms

  • Gauge reading too high or barely falling as the tank empties
  • Engine stalls from fuel starvation with an apparently quarter-full tank
  • Check engine lamp on

Repair estimate

DifficultyMediumDIY possible
Parts and labour€120–650
Time1–3.5 h

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

Parts involved

fuel level sensor b

Related codes

P25B0P25B2P2065P2066P25DC

References: fordservicecontent.com, fordservicecontent.com, performanceparts.ford.com, gsi.ext.gm.com.