Technical Description of OBD-II Trouble Code
The code P2259 refers to the Secondary Air Injection System Control B Circuit being low.
What is the meaning of P2259?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to many OBD-II vehicles (1996-newer). This includes vehicles from Mazda, BMW, Ford, Dodge, Saab, Range Rover, Jaguar, etc. Although it is a generic code, the exact repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
When a P2259 code is stored, it means that the powertrain control module (PCM) has detected low voltage on the secondary air injection control circuit designated as B. To determine the B location for your specific application, refer to a vehicle-specific repair manual.
The secondary air injection system consists of a belt-driven or electric pump that injects ambient air into the engine exhaust system to reduce emissions. Heat-resistant, silicon-based hoses supply the pump with cool ambient air, which is filtered before being drawn in through the air filter housing or a remote inlet housing designed for the secondary air injection system.
Ambient air is pumped into the exhaust system through high-temperature silicon and steel lines attached to ports in the exhaust downpipes. One-way check valves are fitted into each exhaust hose to prevent condensation from entering the pump and causing a malfunction. These valves often fail.
The PCM controls the operation of the secondary air injection pump based on factors such as engine temperature, engine RPM, throttle position, etc. These factors can vary depending on the vehicle manufacturer.
If the PCM detects insufficient voltage on the secondary air injection system control circuit B, it will store a code P2259 and illuminate the malfunction indicator lamp (MIL). The MIL may require multiple ignition cycles with a failure for illumination.
Components of the secondary air injection system:
What is the severity of this DTC?
Conditions that contribute to a stored code P2259 could result in damage to the secondary air injection pump. Therefore, this code should be considered severe.
What are some of the symptoms of the code?
Symptoms of a P2259 trouble code may include:
What are some of the common causes of the code?
Causes for this code may include:
What are some P2259 troubleshooting steps?
To accurately diagnose a code P2259, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable source of vehicle information.
You can save time by searching for technical service bulletins (TSB) that match the stored code, vehicle information (year, make, model, and engine), and exhibited symptoms. This information can be found in your vehicle information source. If you find the right TSB, it may provide a quick solution to your diagnosis.
After connecting the scanner to the vehicle diagnostic port and retrieving all stored codes and freeze frame data, write down the information in case the code is intermittent. Then, clear the codes and test drive the vehicle until one of two things happens: the code is restored or the PCM enters readiness mode.
If the PCM enters readiness mode at this point, diagnosing the code may be more difficult because it is intermittent. The condition that caused the P2259 code to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, continue with the diagnosis.
You can obtain connector face views, connector pinout charts, component locator charts, wiring diagrams, and diagnostic flow charts related to the code and vehicle in question from your source of vehicle information.
Perform a visual inspection of the related wiring and connectors. Repair or replace any wiring that is cut, burned, or damaged.
Use the DVOM to test the control voltage of the secondary air injection system at the appropriate connector pin. If no voltage is detected, check the system fuses and replace any blown or defective fuses as necessary.
If voltage is detected, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the sensor in question and the PCM. If voltage is discovered there, suspect a defective PCM or PCM programming error.
