Code P0402 is interpreted as Exhaust Gas Recirculation Flow Excessive Detected. The code is activated when the Engine Control Module (ECM) recognizes that the Engine Exhaust Gas Recirculation valve (EGR valve) is passing excessive re-circulated exhaust gases into the intake manifold when it is instructed to do so.
To give you a complete outline of code P0402, we’ll tell you all about its symptoms, causes and repairs:
Symptoms of code P0402
The most common symptoms of code P0402 are:
- If the code has been detected by the ECM, then it would set off the Check Engine Light. Moreover, the code would also be saved in the memory of the ECM.
- One common symptom which most of the cars have when they deal with this code is that their engines start running rough because of the stuck opened valve. A good example of this occurrence could be code P0402 in Volvo S70.
Causes of code P0402
Some of the prominent causes of code P0402 are:
- The valve of the EGR is opening completely because there is a blocked vacuum diaphragm in the back pressure valve of the EGR vacuum.
- When the EGR temperature sensor is reading excessive temperature change due to the valve of the EGR which is stuck open. This happens because of a partially blocked exhaust catalyst which leads to the build-up of excessive pressure in the system.
Repairs for code P0402
For instance, there has been a detection of code P0402 in Volvo S70. The most probable repairs which the mechanic could execute to solve this code would be:
- Replacing the entire EGR valve unit as the older one could be either jabbed or damaged.
- In case there is a broken catalyst in the exhaust of the car, the most suitable repair would be to replace the entire component.
- If the EGR temperature sensor is recording excessive temperature change, cleaning the carbon off the sensor could do the work.
This sums up the complete outline for code P0402.