Powertrain, generic · Auxiliary emission controls

P0463 Fuel Level Sensor A Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The fuel level sensor is a float on a resistor track in the tank unit. It is no emission part, but other monitors depend on it – the EVAP leak tests, for example, need at least 15 % fuel – so CARB requires it to be monitored and the usual exemption from the warning lamp does not apply. Low and high refer to the signal, not the fuel level: on GM a full tank is about 40 Ω and a low voltage, while Ford judges the resistance directly. P0463 means the signal is above its upper limit: GM above 60 % of the 5 V reference (100 of 125 samples, MIL after two trips), Saab 9-4X above 4.7 V for 5 s, Ford a resistance above 200 Ω for 30 s. Typical is an open circuit – the pull-up then drives the signal high – a short to positive, or an interrupted resistor track. The gauge sticks at one end and a substitute value is used.

Likely causes

Signal or ground wire open, or tank unit connector off
Resistor track interrupted or worn (sulphur deposits, wiper lifting)
Corroded connector or pushed-back pin
Signal wire shorted to positive

Symptoms

  • Fuel gauge wrong, stuck or jumping
  • Range display and low-fuel warning wrong
  • Check engine light (depending on the maker)

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–600
Time0.5–3 h

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

Parts involved

fuel level sensor afuel tank unitsensor wiringengine control module

Related codes

P0460P0461P0462P0464P2068

References: gsi.ext.gm.com, fordservicecontent.com, saabwisonline.com, saabwisonline.com.