P2556 · Manufacturer communications

FREIGHTLINER, MERCEDES-BENZ · 2026-08-03

Complaint Low Coolant warning with possible engine misfire caused by a leaking Charge Air Cooler (Intercooler), accompanied by one or more of the following possible fault codes related to the coolant system: P30040B: Component 'Temperature sensor downstream of charge air cooler' has an open circuit or short circuit to positive. P25567B: Sensor 'Coolant level' has a malfunction. The fluid level is too low. Cause The potential causes for this topic are: A. A leak in the Coolant System, other than the Charge Air Cooler. B. An Internal leak of the Charge Air Cooler. C. An unapproved/aftermarket upfit or modification to the coolant system. Remedy A. A leak in the Coolant System, other than the Charge Air Cooler 1. Complete a coolant system pressure test: •Refer to WIS Doc AR20.00‐D‐1011TS ‐…

FREIGHTLINER, MERCEDES-BENZ · 2025-04-21

Low Coolant Warning, Potential Misfire, and Absence of External Coolant Leaks Complaint Low Coolant warning with possible engine misfire caused by a leaking Charge Air Cooler (Intercooler), accompanied by one or more of the following possible fault codes related to the coolant system: P30040B: Component 'Temperature sensor downstream of charge air cooler' has an open circuit or short circuit to po- sitive. P25567B: Sensor 'Coolant level' has a malfunction. The fluid level is too low. Cause The potential causes for this topic are: A. A leak in the Coolant System, other than the Charge Air Cooler. B. An Internal leak of the Charge Air Cooler. C. An unapproved/aftermarket upfit or modification to the coolant system. Remedy A. A leak in the Coolant System, other than the Charge Air Cooler 1.…

MERCEDES-BENZ · 2025-03-21

Complaint A "Coolant level too low" warning message is shown in the instrument cluster. Fault code P25567B ('Coolant level' sensor has detected a fault, fluid level is too low.) is stored in the signal acquisition and actuation module (SAM) control unit N10. Cause The vehicle's electric drive motor transports air into the cooling system. The air transported into the cooling system leads to the formation of an air cushion in the expansion reservoir, which in turn causes the coolant level to drop below the warning threshold of the coolant's fill level sensor when driving. After opening the closing cap, the coolant level is OK again. Remedy Replace the black cap A210 501 06 15 of the large working chamber of the expansion reservoir with a red cap A297 500 51 00 and the coolant level rises by…

MERCEDES-BENZ · 2024-08-30

Complaint "Coolant level too low" warning message is shown in the instrument cluster. Fault code P25567B (The 'Coolant level' sensor has a malfunction. The fluid level is too low) is stored in the signal acquisition and actuation module (SAM) control unit N10. Cause The electric drive motor of the vehicle conveys air into the cooling system. The air conveyed into the cooling system leads to an air cushion forming in the expansion reservoir, which in turn causes the coolant level to fall below the warning threshold of the coolant level sensor during travel. After the cap is opened, the coolant level is once again OK. Remedy Replace the black cap A210 501 06 15 of the large working chamber of the expansion reservoir with a red cap A297 500 51 00 and increase the coolant level by 20 mm over…