Error Code P046D is defined as Exhaust Gas Recirculation Sensor A Circuit Intermittent.
This code is a generic trouble code, meaning it applies to all cars equipped with OBD-II, especially made since 1996 up to present. Specifications on the definition, troubleshooting and repairs, of course, vary from one make and model to another.
The job of the EGR valve is to introduce a regulated level of exhaust gas into the intake manifold to maintain the cylinder head temperature of 2500˚ F. NOx (oxides of Nitrogen) are formed when the temperature goes over 2500˚ F, and NOx is responsible for atmospheric pollution and smog.
Error Code P046D is detected when the PCM (powertrain control module, or ECM engine control module in other 2017 Volvo S90 makes) detects an abnormally low, high, or non-existent signal voltage.
Error Code P046D is a similar problem to all cars. But since there are many types of EGRs, sensors, and methods of activation, the only similarity can be that they all vent exhaust gas to the intake manifold to cool the cylinder head temperatures.
Presenting consumed exhaust gas into the engine at the wrong time reduces horsepower, causing your 2017 Volvo S90 to idle rough or stall. Thus, computer programming only opens the EGR when the RPM goes over 2000 and closes when under a load.
As with other error codes, this code activates the Check Engine light and registers the code to your 2017 Volvo S90 ’s system. Other symptoms depend on the EGR’s pintle position when the failure occurred.
In some cases, there can be no symptoms at all.
There are different factors that can lead to this code, such as:
In diagnosing this code, keep in mind that the wiring differs from one manufacturer to another, and computers may not react well if the wrong wire is probed. Probing the wring wire will send excessive voltage through the computer’s sensor input terminal, and may fry the computer.
Also, if the wrong connector is disconnected, the computer could lose all of its programming, causing your 2017 Volvo S90 to fail start again. If this happens, your 2017 Volvo S90 must be taken to the dealer to reprogram the computer.
To start the diagnosis, technicians usually check the EGR sensor connector first and look for signs of corrosion, bent, or pushed out terminals, and loose connections. Then they clean off any corrosion and re-seat the connector.
Next, they proceed on removing the electrical connector and the EGR. Then they check for coking in the EGR intake and exhaust. They clean out any coking present to allow the pintle to move up and down smoothly.
Then they check the vacuum line from the EGR to the solenoid, look for any defects and damages and replace it if there are any damages found.
Next, they check the solenoid electrical connector and look for signs of corrosion and damages.
For Ford cars, technicians will have to follow the two vacuum hoses from the EGR to the DPFE (Differential Pressure Feedback EGR) sensor in the rear of the manifold.
Next, they check the two pressure hoses and look for signs of corrosion. These hoses usually clog carbon from the exhaust. Thus, technicians will use a small pocket screwdriver or equivalent to clean the hoses from corrosion, and the sensor will start running again.
Common repairs include:
Failure in the wiring harness and sensor is the most common cause of this code. Thus it’s important to refer to the service manual of your 2017 Volvo S90 to determine the proper wire identification and diagnostics procedure of this error code.
If the common test fails to solve the problem, a service manual is needed to test the wiring circuits. In such case, the best solution for this is to take your 2017 Volvo S90 to a service facility with the right diagnostic equipment. Professional technicians can identify and repair this problem quickly.