Fault code P2426 is called “Exhaust Gas Recirculation (EGR) Cooling Valve Control Circuit Low” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P2426
Stored code P2426 means that the Powertrain Control Module (PCM) has detected insufficient voltage in the Exhaust Gas Recirculation Cooling Valve (EGR) control circuit. EGR cooling systems are only used in diesel engines.
The exhaust gas recirculation system is designed to feed a portion of the inert exhaust gases back into the engine intake system. Replacing the exhaust gases with oxygen-rich air reduces the amount of nitrogen oxide (NOx) particles.
EGR cooling systems are used to reduce the temperature of the gases before they enter the engine’s air intake system. An electronically controlled EGR cooling valve regulates the flow of engine coolant to the EGR cooler under certain conditions.
The PCM uses input signals from the engine coolant temperature sensor (ECT) and the EGR cooler temperature sensor/s. To determine when and to what extent the EGR coolant valve opens or closes. The PCM monitors the EGR coolant valve control system voltage each time the key is turned on.
The EGR cooler temperature and EGR cooler temperature sensors report changes in engine coolant temperature to the PCM. The PCM compares these input signals to calculate whether the EGR cooling system is operating properly.
The EGR system temperature sensors are usually located near the EGR valve. And the ECT sensors are usually located in the water jacket of the cylinder head or water jacket of the intake manifold.
If the EGR valve control system voltage is too low, below the normal range of programmed parameters. Or if the input signals from the EGR temperature sensor/sensors are not the same as the ECT sensor signals, error code P2426 will be stored. The malfunction indicator lamp may also illuminate.
Symptoms of vehicle malfunctions
The main signal that an error P2426 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The Check Engine light on the control panel will illuminate (the code will be written to the ECM memory as a fault).
- There may also be emission temperature sensor codes present.
- There may be additional engine temperature sensor errors.
- The exhaust gas recirculation system may have other failures due to accumulation of carbon or soot in the system.
- The engine may fail an emissions test.
- A knock may be heard during acceleration.
- Reduced engine performance.
- Increased fuel consumption.
- There may be no symptoms other than a stored fault code.
The severity of code P2426 can range from moderate to severe, depending on the specific symptoms of the fault. As well as the level of performance of the cooler and bypass valve.
A faulty exhaust recirculation valve or control circuit, can cause excessive ignition, as well as early ignition. This can cause damage to pistons, valves, and other related internal engine components.
Factors that can cause this error code
The error code P2426 can mean that one or more of the following problems have occurred:
- Dirty or clogged exhaust gas recirculation system.
- Faulty EGR relay or temperature sensor.
- Excessive soot or carbon buildup on walls.
- Short-circuited or broken electrical wiring relating to the EGR system.
- Weakened, corroded, or damaged electrical connectors related to the exhaust gas recirculation system.
- The engine coolant level is low.
- Engine overheating.
- The cooling fan of the exhaust gas recirculation system is defective.
- In rare cases, engine control module (ECM) malfunction.
How to fix or reset OBD-2 code P2426
Some suggested steps for troubleshooting and fix the error code P2426:
- Connect an OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Clear the error codes from the computer memory and test-drive the vehicle to see if error code P2426 appears again.
- If the error code appears again, visually inspect the electrical wires and connectors related to the exhaust gas recirculation system.
- If necessary, repair or replace any shorted, broken, damaged, or corroded components.
- If the problem persists, check the exhaust recirculation system ducts for blockage.
- Check the operation of the exhaust gas recirculation cooling valve.
- Measure the circuit voltage with a digital multimeter.
- Compare with the value in the manufacturer’s data sheet, and replace the faulty valve if necessary.
- If the problem persists, check and replace the engine control module (ECM) if necessary.
Diagnose and repair of problems
The first step in the P2426 troubleshooting process, is to review the Technical Service Bulletins (TSB). For known problems with a particular vehicle.
The advanced diagnostic steps are very vehicle specific. It may require, special equipment and knowledge to accurately perform the steps.
Allow your vehicle’s engine to cool down. In most cases, exhaust gas recirculation systems are very hot. Since they are usually installed directly on the exhaust system. Therefore, if you don’t let the engine cool down, you can get burned.
Visual damage
Locate all of the components associated with the exhaust gas recirculation cooler circuit and examine them for obvious physical damage. Depending on the specific vehicle, this circuit may include several components. Temperature switch, bypass valve, exhaust gas recirculation valve, exhaust gas recirculation cooler and engine control unit.
Perform a thorough visual inspection to check the wiring for obvious defects such as scratches, scuffs, exposed wires or burn spots. Next, check connectors and connections for safety, corrosion, and contact damage.
Be sure to carefully check the integrity of the wire harnesses. They often run along and around the exhaust pipe. Therefore, you need to secure any loose wires. If you find a burned wire, solder it and make sure it is properly insulated.
Voltage check
When checking the voltage, you need to identify the absence of a power source or ground. This requires checking the continuity of the wiring, connectors, and other components.
Normal resistance readings for wiring and connections should be 0 ohms. The presence of resistance or lack of continuity indicates faulty wiring. Which is open, shorted, or corroded and should be repaired or replaced.
Reference voltages and allowable ranges may vary depending on the specific vehicle and circuit configuration.
If all of the EGR cooling valve control sensor circuits are serviceable, but error P2426 still appears. Use an infrared thermometer to check the EGR cooler (valve) inlet and exhaust gas temperature. Compare the results with the manufacturer’s specifications and replace faulty EGR cooling system components if necessary.
On which vehicles does this problem occur most frequently
Fault code P2426 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Audi
- Dodge
- Ford
- Honda (CR-V)
- Mitsubishi (ASX)
- Nissan (Navara, Pathfinder)
- Volkswagen (Golf, Passat)
Fault code P2426 can sometimes be found with other errors. The most common are the following: P2413, P2425, P2427, P2457.
