13 miles to the gallon
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
P1409 EVR Control Circuit Malfunction
Yep, that will definitely cost you mpg's.
Your EVR is spent, or the circuit is rather. How it works -
In the schematic the PCM has commanded the EVR to open the EGR valve to vacuum from the inlet manifold, and the EGR poppet valve is open, providing a flow of exhaust gas into the inlet manifold. The DPFE sensor is sampling the gas flow and returning a reading to the PCM, which can vary the opening of the EGR valve by varying the voltage to the EVR while making adjustments to the timing of the ignition. This provides better emissions and economy. This operation has been compromised, so mileage suffers.
Yep, that will definitely cost you mpg's.
Your EVR is spent, or the circuit is rather. How it works -
In the schematic the PCM has commanded the EVR to open the EGR valve to vacuum from the inlet manifold, and the EGR poppet valve is open, providing a flow of exhaust gas into the inlet manifold. The DPFE sensor is sampling the gas flow and returning a reading to the PCM, which can vary the opening of the EGR valve by varying the voltage to the EVR while making adjustments to the timing of the ignition. This provides better emissions and economy. This operation has been compromised, so mileage suffers.
Thread Starter
|
Member
Joined: Oct 2011
Posts: 20
Likes: 0
From: canyon tx
so how do you fix that
Technical Article Contributor
Joined: Oct 2005
Posts: 25,641
Likes: 19
From: MI
Check continuity first. The wires like to break inside the insulation, at the bends and close to the connector. Flex the harness while checking as the break can reconnect inside it's insulation when repositioned. Know what I mean ? Don't let that fool you.
Then check references,VPwr/VRef. You can also pop the cap and clean the internal filter. You can remove, once cap is removed.
The EVR regulates the vacuum to the EGR valve and is controlled by a pulse-width signal to open and close the EGR valve. As the duty cycle pulse width signal increases, the EVR increases the vacuum to the EGR which opens further and admits more gas into the inlet system.
Vacuum not directed to the EGR valve is vented to atmosphere. Even at zero duty cycle (no voltage) some vacuum will still pass the EVR, but this is not enough to overcome the spring pressure. It is not until the EVR is at 40% duty cycle that the vacuum is enough to overcome the EGR spring pressure.
The Schematic references ^^^
Then check references,VPwr/VRef. You can also pop the cap and clean the internal filter. You can remove, once cap is removed.
The EVR regulates the vacuum to the EGR valve and is controlled by a pulse-width signal to open and close the EGR valve. As the duty cycle pulse width signal increases, the EVR increases the vacuum to the EGR which opens further and admits more gas into the inlet system.
Vacuum not directed to the EGR valve is vented to atmosphere. Even at zero duty cycle (no voltage) some vacuum will still pass the EVR, but this is not enough to overcome the spring pressure. It is not until the EVR is at 40% duty cycle that the vacuum is enough to overcome the EGR spring pressure.
The Schematic references ^^^