Mk4 2.3 Petrol P1408

[siacelestar]

Seeking help.... 08 Mk4 2.3 Petrol auto..

After changing the engine mount and disconnected the battery for inspecting the transmission mount, when started up the car went lumpy at idle, slow picking up speed and smell of unburnt fuel from the exhaust. Forscan showed no error but when doing KOER test P1408 - EGR out of self-test range.

Cleaned the EGR valve and tested with a new valve but no help - same message still came up everytime. Although with the cleaned EGR valve it actually runs fine - still got white smoke out of the tailpipe but that's probably due to the gasket leaking so new one is on the way. 

What could the 'out of self test range' be caused by? I am thinking it could be some sensor being dirty and carboned up (throttle body also cleaned as it was quite carboned up) but the only sensor that's in the air flow would be the two HEGO sensors down on the exhaust side as there seems to be no sensor on the intake side...

Thanks in advance!

[FatHead1979]

On 11/25/2020 at 4:21 PM, siacelestar said:

Seeking help.... 08 Mk4 2.3 Petrol auto..

After changing the engine mount and disconnected the battery for inspecting the transmission mount, when started up the car went lumpy at idle, slow picking up speed and smell of unburnt fuel from the exhaust. Forscan showed no error but when doing KOER test P1408 - EGR out of self-test range.

Cleaned the EGR valve and tested with a new valve but no help - same message still came up everytime. Although with the cleaned EGR valve it actually runs fine - still got white smoke out of the tailpipe but that's probably due to the gasket leaking so new one is on the way. 

What could the 'out of self test range' be caused by? I am thinking it could be some sensor being dirty and carboned up (throttle body also cleaned as it was quite carboned up) but the only sensor that's in the air flow would be the two HEGO sensors down on the exhaust side as there seems to be no sensor on the intake side...

Thanks in advance!

Barely any MK4's were sold in the UK with the 2.3 petrol engine and the Mondeo forum on here isn't the busiest.  You might be better off trying https://talkford.com/community/forum/471-petrol-engines-mk4-mondeo (if you haven't already)

[siacelestar]

12 hours ago, FatHead1979 said:

Barely any MK4's were sold in the UK with the 2.3 petrol engine and the Mondeo forum on here isn't the busiest.  You might be better off trying https://talkford.com/community/forum/471-petrol-engines-mk4-mondeo (if you haven't already)

I did put up a post over there but not a single response.......

[Tdci-Peter]

On 11/25/2020 at 4:21 PM, siacelestar said:

What could the 'out of self test range' be caused by?

I am thinking it might be that it needs to relearn its end positions. Self test sounds like it is testing the built in position sensor in the valve, compared to the operating movement of the valve. It seems to have a 6 pin electrical connector (if I have found the right part!), so is almost certainly a standard electric motor with pot type position feedback.

There could be a problem with this internal sensor, and the new one tried have also not have matched the current calibration, or it may have just lost its settings with the battery disconnect.

Have a good hunt round in Forscan (connected to the car), to see if there is a service procedure for this. A general PCM reset or relearn may be an option if there is nothing specific.

[siacelestar]

Checked the wiring, and the 6 wires are all for controlling the position of the stepper motor inside the EGR unit. The only code pops up is the P1408 which only occurs for the engine test and not for anything else, the only sensor that dictates the air would be the oxygen sensor on the exhaust side. Part ordered and will see if it helps.....

[Tdci-Peter]

2 hours ago, siacelestar said:

the 6 wires are all for controlling the position of the stepper motor inside the EGR unit.

I forgot about the stepper motor possibility. They are quite rare on Fords, the servo motor design is cheaper and in most ways, better, as it includes absolute position sensing.

If the car has both a MAF (inlet airflow) and a MAP (inlet manifold pressure), then these can be used by the ECU to estimate EGR flow, (knowing rpm, and inlet temperature as well), and be compared to expected flow from the EGR position calculated from the step count. This is how the EGR is controlled in many Fords. The O2 sensors do not indicate the EGR flow unless the intake flow (MAF, or the MAP+Temp+RPM combination) is also known, as they only give %O2. 

Air leaks can also throw out the calibration, by messing up the flowrates.