Fault code P242A is called “Exhaust Gas Temperature (EGT) Sensor Circuit Malfunction (Bank 1, Sensor 3)” 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 P242A
This Diagnostic Trouble Code (DTC) is a generic code. Error P242A is considered a generic code because it applies to all makes and models of vehicles. Although the specific repair steps may vary slightly depending on the model.
EGR is responsible for exhaust gas recirculation. It is part of the vehicle’s exhaust emission system. It is used to reduce temperature, combustion pressure, and to control nitrogen oxides.
The function of the exhaust temperature sensor is to control the temperature in the recirculation system. And regulate the flow accordingly with the exhaust gas recirculation valve. Which is based on a conventional temperature-sensitive resistor-type sensor.
The higher the exhaust temperature, the lower the resistance relative to ground, resulting in a higher voltage. Conversely, the lower the temperature, the greater the resistance, resulting in a lower voltage.
If the PCM detects a change in voltage, the computer changes the timing or fuel ratio. To keep the temperature within an acceptable range inside the converter.
In diesel engines, the reading from the exhaust temperature sensor is used to determine the regeneration time of the particulate filter.
When the Powertrain Control Module (PCM) detects a fault in the exhaust gas temperature sensor circuit (Bank 1 Sensor 3). Fault code P242A will be written to memory and an error message will appear on the control panel.
Symptoms of vehicle malfunctions
The main signal that an error P242A has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Check engine control lamp on the control panel will light up (the code will be recorded in the memory as a malfunction).
- Increased engine noise, also there may be ringing and rattling.
- Increased emission of harmful substances in the exhaust.
- Excessive exhaust odor.
- There may be other symptoms as well.
Technically, error P242A is not considered serious, but in environmental terms, there is a strong increase in emissions. However, it is necessary to correct the problem, because any malfunction can lead to more serious consequences.
Factors that can cause this error code
The error code P242A can mean that one or more of the following problems have occurred:
- Exhaust gas temperature sensor is defective.
- Short circuit to ground or inside the exhaust temperature sensor.
- Leak in the exhaust gas recirculation temperature sensor gasket.
- Cracked or leaking exhaust pipe where the sensor is installed.
- The wiring harness or sensor may be damaged.
- Wires are open or shorted.
- Damaged connector.
- An aftermarket exhaust system installation that is causing pressure problems.
- Intermittent communication with the control unit.
- Sometimes faulty ECM module is the cause.
How to fix or reset OBD-2 code P242A
Some suggested steps for troubleshooting and fix the error code P242A:
- Clear the error codes and test drive the vehicle to see if code P242A appears again.
- Visually inspect the exhaust temperature sensor and all related circuits, especially where they come in contact with hot components.
- Check connectors for looseness and corrosion.
- Inspect the wires for damage that could cause a short circuit.
- Check the resistance of the exhaust temperature sensor with an ohmmeter.
- Test the exhaust temperature sensor.
- Check for leaks in the system.
- Test the ECM module and its communication.
Diagnose and repair of problems
First you must read all saved data and error codes with the scan tool. Then clear the error codes and test-drive the vehicle. To find out if error P242A appears again.
After that, visually inspect the exhaust temperature sensor, it is worth paying attention to exhaust leaks. Also check the sensor itself and the wiring harness that goes to it. High temperatures can damage plastic and rubber insulated wires, so check them carefully.
Black soot can indicate an exhaust leak, so inspect the connections carefully.
Check the EGR sensor and system
Many exhaust gas recirculation problems are caused by soot buildup in the exhaust. Therefore, it may be helpful to clean the EGR system, or at least the temperature sensor.
After removing the sensor, use a carburetor cleaner or similar product to effectively soak up the soot. Use a metal brush to remove soot from excessively accumulated areas. When reinstalling a clean sensor, be sure to apply an anti-seize compound to the threads to prevent seizing.
Use a hair dryer or heat gun to test the sensor, watching for an ohmmeter. The resistance should drop as the sensor heats up and rise as it cools down; if it does not, replace it.
If the sensor itself is faulty, you can install a 2.2 ohm resistor to eliminate code P242A as a temporary measure. Simply remove the EGT sensor and connect the resistor to the electrical connector on the engine side, isolate it, and the computer will verify that the EGT is working properly.
On which vehicles does this problem occur most frequently
Fault code P242A 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 (A6, Q7)
- Ford (F-250)
- Nissan (Qashqai, X-Trail)
- Volkswagen (Golf, Passat, Touareg, Transporter)
Fault code P242A can sometimes be found with other errors. The most common are the following: P242B, P242C, P242D, P242E.