Technical Description of OBD-II Trouble Code
The circuit for the Secondary Air Injection System Switching Valve A is open.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to OBD-II equipped vehicles such as Dodge, Ram, Ford, GMC, Chevrolet, VW, Toyota, etc. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
When encountering code P0413, it indicates that the powertrain control module (PCM) has detected a malfunction in the circuit of a secondary air injection (SAI) system switching valve. The specific switching valve in question is designated as A. The A designation refers to a particular switching valve in a system that may have multiple switching valves or the only valve if there is just one.
In diagnostic terms, the word “open” can be replaced with “disconnected,” “broken,” or “cut.” To determine the configuration of the SAI switching valve circuits for the specific vehicle and the exact location of switching valve A, consult a reliable vehicle information source. The SAI system injects ambient air into the engine exhaust system as a means of reducing harmful exhaust emissions. Most automotive SAI systems use a belt-driven pump to draw in ambient air, slightly compress it, and inject the pressurized air into the engine exhaust manifolds.
The PCM controls one-way valves, switching valves, anti-backfire valves, and bypass valves to regulate and distribute air pressure and protect the SAI pump. Voltage input signals from strategically placed pressure sensors are received by the PCM to monitor fluctuations in SAI system pressure. When the required parameters are met, the PCM electronically opens the necessary valves, allowing secondary air to be pumped into the exhaust system.
Some vehicles are equipped with SAI systems that have an electronic pump. In such systems, the PCM monitors pressure sensors and activates the pump when necessary.
If the PCM detects a low or non-existent voltage input signal from the SAI switching valve (designated as A), it will store a code P0413 and may illuminate a malfunction indicator lamp.
Other trouble codes related to the secondary air injection system include P0410, P0411, P0412, P0414, P0415, P0416, P0417, P0418, P0419, P041F, P044F, P0491, and P0492.
Code Severity & Symptoms
The SAI system is only related to reducing exhaust emissions and is not essential for engine operation. Therefore, a stored code P0413 should not be considered severe.
Symptoms associated with this code may include:
Causes
Possible causes for this code to be set are:
Diagnostic and Repair Procedures
To diagnose a code P0413, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source.
Start the diagnosis by inspecting the system wiring, connectors, and the serpentine belt that drives the pump (if applicable). Repair or replace any open circuits as necessary and retest the system. If the pump is belt-driven and the belt is missing or defective, replace it before proceeding. Ensure that the pump spins freely by hand before replacing the belt. Pump failure is relatively common in high mileage vehicles. If the SAI pump is driven by an electric motor, it is also recommended to check system fuses and relays at this time.
If a visual inspection does not reveal any obvious malfunctions, connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. This information may be useful in the diagnosis, so it is recommended to write it down. Clear the codes and test drive the vehicle to see if the P0413 code is reset.
Consult a vehicle information source to search for technical service bulletins (TSB) that match the code/s and symptom/s exhibited by the specific vehicle. TSBs contain valuable information based on data from numerous repairs and can assist in reaching a successful diagnosis.
In extremely cold weather conditions, belt-driven SAI pumps are prone to lockup due to frozen condensation. Typically, an air inlet hose incorporates a one-way check valve to prevent condensation from reaching the SAI pump. However, these check valves often fail and allow condensation from the exhaust to enter the SAI pump. When the condensation freezes, it can either seize the SAI pump (in belt-driven systems) or cause it to bind and blow a fuse (in electric pump systems).
Use the scanner to activate the electric SAI pump. Once the pump is activated, use the DVOM to test voltage and ground at the SAI pump. If no voltage is detected, suspect a blown fuse or a faulty power supply relay. If all fuses and relays are functioning properly, use the DVOM to check for an open circuit between the power supply source and the pump. Disconnect all related controllers before using the DVOM to check circuit resistance. If no ground is detected, consult the vehicle information source to locate the appropriate ground source and test voltage drop in the circuit.
Test the SAI pressure sensor using the DVOM and the specifications provided in the chosen vehicle information source.
Additional diagnostic notes:
