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U0698 Lost Communication With Coolant Pump E

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Coolant pump E continues the generic letter series of auxiliary electric pumps after A to D. Mercedes-Benz uses it for the second coolant pump in its low-temperature circuit: bulletin LI20.00-P-076708 lists U0698E4 and U0698E5 in the powertrain control unit N127 together with other LIN devices such as fan, charge-air cooler pump and high-temperature control valve. Affected are the GLC (254) and the 2024 facelift GLE (167); drivers see the check engine lamp, a coolant warning and the radiator fan at maximum speed. On the GLC with control unit software 22A the fix is a software update; otherwise connectors, wiring and intermediate connections on the LIN bus are checked. Pumps like Bosch's PDE take speed commands via PWM or LIN and diagnose themselves.

Likely causes

Powertrain control unit software (Mercedes N127 version 22A)
LIN wiring or intermediate connector chafed or corroded
Pump E electronics failed

Symptoms

  • Check engine light
  • Coolant warning message
  • Radiator fan running at full speed

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–700
Time0.3–3 h

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

Parts involved

coolant pump evehicle bus wiring

Related codes

U0699U0623U0624U062FU0649P2DF4P2DF8P2D26

References: static.nhtsa.gov, static.nhtsa.gov, bosch-mobility.com.