Technical Description of OBD-II Trouble Code
The circuit for the Engine Coolant Level Sensor/Switch is registering a high level.
What does that mean?
This is a generic diagnostic trouble code (DTC) for the powertrain and is applicable to many OBD-II vehicles manufactured from 1996 onwards. This includes vehicles from Audi, Ford, BMW, Lincoln, Chrysler, and others. While it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
OBD-II trouble code P2559, along with related codes P2556, P2557, and P2558, are associated with the engine coolant level sensor and/or switch circuit.
Some vehicles are equipped with a coolant level sensor or switch. It typically operates using a float mechanism, similar to the gas gauge sending unit. If the coolant level drops below a certain 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 higher than the normal expected range, code P2559 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 P2559 trouble code may include:
What are some of the common causes of the code?
Causes for this P2559 code may include:
What are some P2559 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 based on its year, model, and engine/transmission configuration. In some cases, this can save a significant amount of time by providing guidance in the right direction.
The second step is to locate all components associated with the engine coolant level circuit and inspect them for any obvious physical damage. The sensor or switch may be located in the coolant reservoir or overflow bottle, or in the radiator. Consult a vehicle-specific repair manual to determine the exact location in your vehicle.
Conduct a thorough visual inspection to check the associated wiring for any visible defects such as scraping, rubbing, bare wires, or burn spots. Next, examine the connectors and connections for security, corrosion, and damaged pins. This process should include all wiring connectors and connections to all components, including the PCM. Refer to the specific technical data for the vehicle to verify the configuration of the coolant level safety circuit and determine if a fuse or fuse-able link is part of the circuit.
Advanced Steps
The advanced steps are highly specific to the vehicle and require advanced equipment to be performed accurately. These procedures necessitate the use of a digital multimeter and the specific technical references for the vehicle. In this situation, an oil pressure gauge may aid in the troubleshooting process.
This article is purely informational, and the specific technical data and service bulletins for your vehicle should always take precedence.
