Technical Description of OBD-II Trouble Code
The circuit range/performance of the Engine Coolant Level Sensor/Switch
What does that signify?
This is a generic powertrain diagnostic trouble code (DTC) that is applicable to many OBD-II vehicles (1996-newer). This includes vehicles from Audi, Ford, BMW, Lincoln, Chrysler, and others. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration.
OBD-II trouble code P2557 and related codes P2556, P2558, and P2559 are associated with the engine coolant level sensor and/or switch circuit.
Some vehicles are equipped with a coolant level sensor or switch. Typically, it operates using a float similar to the gas gauge sending unit. If the coolant level drops below a specific level, the circuit is completed and the PCM (powertrain control module) sets this code.
When the PCM detects voltage or resistance in the engine coolant level sensor/switch circuit that is outside the expected range or performance parameters, code P2557 is set and the check engine or low coolant/overheating light may illuminate.
What is the severity of this DTC?
The severity of this code is moderate because if the engine coolant level drops too low, there is a potential for the engine to overheat and cause extensive damage.
What are some of the symptoms of the code?
Symptoms of a P2557 trouble code may include:
What are some of the common causes of the code?
Causes for this P2557 code may include:
What are some P2557 troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to research the Technical Service Bulletins (TSB’s) for the specific vehicle by year, model, and engine/transmission configuration. In some circumstances, this can save a lot of time in the long run by pointing you in the right direction.
The second step is to locate all components associated with the engine coolant level circuit and look for obvious physical damage. Possible locations for this sensor or switch may include the coolant reservoir or overflow bottle, or the radiator. Refer to a vehicle-specific repair manual to determine the location in your vehicle.
Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burn spots. Next, check the connectors and connections for security, corrosion, and damaged pins. This process must include all wiring connectors and connections to all components, including the PCM. Consult the specific tech data for the vehicle to verify the configuration of the oil level safety circuit and see if a fuse or fuse-able link is incorporated into the circuit.
Advanced Steps
The advanced steps become very vehicle-specific and require the appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and the specific technical references for the vehicle. In this situation, an oil pressure gauge may facilitate the troubleshooting process.
This article is strictly informational, and the specific technical data and service bulletins for your vehicle should always take priority.
