[Joda]

Hi!
This car is solved and also 3 more EGR this type is solved without to make them off or changing the EGR body or the complete EGR unit.

So, the problem is in the electronic circuit board which is in the motor housing.

1.
The DTC P0403 is triggered if the EGR is stuck open and the voltage on the motor
connector pin 3 and 5 are 4.01V.
4.01V means an open valve.

Or!

2.
If something is wrong with the electronic in the EGR motor housing and the electronic sends the
signal to the ECU which is actually telling the ECU does the EGR valve is open but it is not.

This code will be triggered only when the car start to using the EGR system.
If the engine temp is not reached the minimum engine temp for using the EGR then it won't be triggered. The diag tool won't recognize this error also.

The DTC P0408 means an EGR signal which has a very low stage.
This means, the voltage between the pin 3 and pin 5 on the EGR motor connector is under 0.71v.
This stage could be a mechanical problem and an electronic problem.

There could also be a DTC P046C which means if the voltage on pin 3 and pin 5 are over 1v when the EGR calve should be closed.
This error could also be a mechanical and electronic problem.

The EGR motor is a 12v DC motor which is driven by the ECU through PWM signal.

Conclusion, before you decide to change the EGR unit and let the customer pay an expensive repairing check the proper way the signal between:

Pin 2 and pin 6 are the motor powering pins which should be checked with a scope and should be a PWM signal present.

Pin 3 and pin 1 are the 5v reference voltage which is feeding from the ECU side to the position rotary IC inside the motor electronic.
Should be checked with a voltmeter.

Pin 3 and pin 5 are the return signal to the ECU and is telling the ECU the actually position of the EGR valve.
Should be checked with a voltmeter.
The value should be:
With the key in ignite position but a not running engine the value should be between 0.7 - 0.9v.
Everything outside this value will trigger a DTC.

In these days I repaired 3 EGR's on 3 car's where mechanics told to buy a new EGR unit.
On all the unit was the DTC P0408 triggered.

I hope this info would be useful...

[bobdinro]

Nice explanation, but the macanichal parts wear? usual the change of complete new EGR unit is a must.

Nice job anyway.

[Joda]

Of course. If the mechanical par are bad then it must be changed.
Thanks for your comment.
I appreciate that.
My best regards.

Sent from my GT-I8260 using Tapatalk

[Tunelos]

Hi!
This car is solved and also 3 more EGR this type is solved without to make them off or changing the EGR body or the complete EGR unit.

So, the problem is in the electronic circuit board which is in the motor housing.

1.
The DTC P0403 is triggered if the EGR is stuck open and the voltage on the motor
connector pin 3 and 5 are 4.01V.
4.01V means an open valve.

Or!

2.
If something is wrong with the electronic in the EGR motor housing and the electronic sends the
signal to the ECU which is actually telling the ECU does the EGR valve is open but it is not.

This code will be triggered only when the car start to using the EGR system.
If the engine temp is not reached the minimum engine temp for using the EGR then it won't be triggered. The diag tool won't recognize this error also.

The DTC P0408 means an EGR signal which has a very low stage.
This means, the voltage between the pin 3 and pin 5 on the EGR motor connector is under 0.71v.
This stage could be a mechanical problem and an electronic problem.

There could also be a DTC P046C which means if the voltage on pin 3 and pin 5 are over 1v when the EGR calve should be closed.
This error could also be a mechanical and electronic problem.

The EGR motor is a 12v DC motor which is driven by the ECU through PWM signal.

Conclusion, before you decide to change the EGR unit and let the customer pay an expensive repairing check the proper way the signal between:

Pin 2 and pin 6 are the motor powering pins which should be checked with a scope and should be a PWM signal present.

Pin 3 and pin 1 are the 5v reference voltage which is feeding from the ECU side to the position rotary IC inside the motor electronic.
Should be checked with a voltmeter.

Pin 3 and pin 5 are the return signal to the ECU and is telling the ECU the actually position of the EGR valve.
Should be checked with a voltmeter.
The value should be:
With the key in ignite position but a not running engine the value should be between 0.7 - 0.9v.
Everything outside this value will trigger a DTC.

In these days I repaired 3 EGR's on 3 car's where mechanics told to buy a new EGR unit.
On all the unit was the DTC P0408 triggered.

I hope this info would be useful...

Are you talking about the PIN's from EGR valve solenoid or ECU!?..because I just changed the valve with a new one DQ code and I still have P0403 with N18 error, so the solenoid have new pins.
Thanks!

[Joda]

Are you talking about the PIN's from EGR valve solenoid or ECU!?..because I just changed the valve with a new one DQ code and I still have P0403 with N18 error, so the solenoid have new pins.
Thanks!

Hi!
You are well come!
That was long time ago, I had to remember me about the situation I had that time.
I'm talking about the pins on the egr side, not the ecu.

When you changed your valve, I think you don't changed the electronic on the egr, just the whole mechanical parts.
You must go through all my steps of measuring because without measuring I don't think you will find the exact problem.

I can remember that time, mechanics also changed the egr valve unit but they don't fixed the problem, they also sent back the new part and got one more part, and also changed, the problem still existed.
Then they called me, I'm an electronics service person and repair car electronics only.

I hope I helped you.
If any questions feel free to ask.
My best regards.

[johndoe22]

Hello. I have the following error:
4891 - EGR Valve (N18)
P0403 00 [237] - Malfunction
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 4
Mileage: 161509 km

I read on the internet about this and I think that it is related to the electronic chip which controls the motor, but the solutions provided by most of the users is replacing the entire EGR system(including cooler)...
Any more solutions/tests? It is possible to repair it?