Powertrain, generic (extended)

P2558 Engine Coolant Level Sensor/Switch Circuit Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2558 reports that the coolant level sensor or switch signal sits too low on the electrical scale. Deutz assigns it on the EMR L1 controller as P2558-14 under SPN 111 and groups two causes together: a grounded line or an interrupted one, which on that input both pull the reading to the bottom. The repair therefore starts by measuring the signal line to ground and checking it for continuity between control unit and tank, including the connector at the expansion tank, which sits in a hot and wet area. Note that a low signal is an electrical finding, not proof that coolant is missing; an actual low level is logged as P2560. On Mercedes passenger cars, by contrast, the level warning is coded P2556-7B. P2559 covers the opposite short to battery, P2557 an implausible value. The coolant level warning can no longer be trusted.

Likely causes

Signal line shorted to ground
Broken wire or corroded connector at the expansion tank
Level sensor internally shorted

Symptoms

  • Permanent low coolant warning despite a full tank
  • No warning possible if the level really drops

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–250
Time0.3–1.5 h

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

Parts involved

coolant level sensorsensor wiring

Related codes

P2556P2557P2559P2560

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