Powertrain, generic (extended)

P2557 Engine Coolant Level Sensor/Switch Circuit Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2557 means the coolant level signal is electrically present but not believable. The Deutz EMR L1 engine control is the one documented user and fills the code twice under SPN 111: P2557-00 for a sensor value outside the valid range, and P2557-1C when the supply voltage feeding the level sensor is itself out of range. The second case is worth checking first, because a weak or overloaded sensor supply skews the reading without any fault at the sensor. Mechanical effects can also confuse a level sensor; Mercedes describes for the EQB how an air cushion in the expansion tank pushed the measured level below the warning mark although enough coolant was present. Shorts to ground or open lines belong to P2558, a short to battery to P2559, and P2556 is the general circuit code. Expect a coolant warning that is unreliable.

Likely causes

Sensor supply voltage out of range (Deutz P2557-1C)
Level sensor element contaminated or failing
Air pocket or foam in the expansion tank distorting the reading

Symptoms

  • Coolant level warning appears and disappears
  • Engine protection warning on industrial engines

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–300
Time0.3–1.5 h

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

Parts involved

coolant level sensorcooling system

Related codes

P2556P2558P2559P2560

References: serdia.deutz.com, static.nhtsa.gov.