Turn AGR on or off via switch

'If you unplug the connector from the EGR control valve, it will generate an error code, but the EGR system will be deactivated. Is it possible to trick the control unit by sending a false feedback signal while the connector is unplugged, thereby preventing the error code from appearing? If this works, you could install a small switch inside the car to enable or disable the EGR system.' Has anyone ever tried that before?

Yes, that should be possible. You only need an electrical dummy that has similar properties to the solenoid coil of the pneumatic valve for the EGR control air.

So, take an ohmmeter and measure the ohmic resistance of the coil. Then, install a resistor with a power rating of 3 watts, and connect it in series with the circuit, using a switch to connect it in place of the solenoid coil.

A potential issue could be the moment of switching, where the connection is open for an extremely short period. I'm not sure if the control unit flags an error in that situation. Or you only switch it on when the ignition is off.

Hello,

Based on my experiments with the AFN, the EDC is very tolerant to the valve's resistance value.
It normally measures around 20 ohms, but my EDC device accepts resistors up to the kOhm range without reporting any errors.

If you're experiencing the same issue, I would suggest connecting a resistor of a corresponding high value in parallel with the valve, and inserting a normally open switch between the resistor and the valve.
For example, with a 2.2 kOhm resistor, a power rating of 1/10 Watt is more than sufficient.

When the switch is open, the EDC still sees the resistor as a valve dummy and doesn't complain (at least) about the resistor .

Hi,

@ulf yes, that's how it works.

But the error entry in the control unit doesn't really have any effect, does it? Then that would be about...
Is the resistance of a coil dummy just cosmetic, or am I mistaken?

Achim wrote:

@ulf yes, that's how it's done. But the error entry in the control unit doesn't really have any effect, does it? Then that would be about... Resistance as a coil dummy is just cosmetic, or am I wrong?

Hi Achim,

Cosmetic fixes to keep the error log clear - that's probably true.

However, I haven't driven it yet with the valve plug removed, so I can't completely rule out a limp-home mode-like reaction.

However, I haven't driven the vehicle yet with the valve plug removed, so I cannot completely rule out a limp-home mode-like reaction.
My G3, engine code AHU, has been running with the connector unplugged for a while. I haven't noticed any behavior similar to a limp-home mode. Whether this applies to all small and medium-sized enterprises (SMEs) is not certain, but it is very likely to apply to the older ones.

Regards,
-Private

Hi,

I once tried using a switch and a 1k, 1/4-watt resistor. I am.
I never thought of connecting the resistor in parallel with the inductor, and then...
simply turning off the coil Sometimes you just end up twiddling your thumbs.
At the time of the switchover, there was, of course, an interruption.
A fault entry in the control unit did not affect the driving characteristics in my case.