Good egr voltages

[the57]

Hi,

2007 focus 1.6tdci can you post known good egr voltage on the connector, back probed with the key on engine off,i got

pin 1-   5v ref

pin 2-  2.65v signal

pin 3-  0.14v ?

pin 4-  0.48v ?

pin 5-  0.01v ground

i think this is bad, should i have 12v on pin 3+4

Thanks

[Tdci-Peter]

On 07/08/2016 at 0:54 PM, the57 said:

2007 focus 1.6tdci can you post known good egr voltage on the connector

I assume the EGR was disconnected, and you were probing the connector on the harness?

According to the drawing I have, the connector pins are

Pins 2 & 3 are the motor drive. Normally these would be the same voltage, as the EGR would be closed (motor de-energised). But with valve disconnected, pcm could be driving it for some odd reason.

Pin 1 is Vref (5v), Pin 5 is Ground (0v), Pin 4 is the feedback signal, so may be floating if the valve is not connected.

If you can make connections to the pins on the EGR, and have a variable power supply (0-12v at about 4A), then it is quite easy to test the valve. (Disconnected, and preferably removed from the car for visibility.)

But resistance tests on the valve are useful: Motor should be low ohms (1 - 4 ohms), pot may be a standard value like 5k or 10k (Mine was about 5.7k, but that was 1.8TDCI), and wiper should be not right at one end, but nearer the ground end (lower resistance to ground).

I suspect problems in the valve are more likely than problems in the harness or pcm.

Any Help?

Peter.

[the57]

connector was connected, i thought the motor should have 12v, and the ecu controls the ground, my drawing shows pins 3+4 are for the motor?

[iantt]

motor should have 12v at connector and is actuated by pulse width modulation signal

[iantt]

sensor signal voltage doesnt look right, approx 1v closed, and 4.2v open it should be.

whats your issue to be probing the egr?

[the57]

got a p042f, the egr was replaced, the signal voltage might be because its stuck open a little, if it should be 12v, i think the next step would be test at the ecu for a short to ground.

[iantt]

disconnect the conector and test pin3 for 12v, that feed comes from battery fuse box, fuse 35.

[Tdci-Peter]

2 hours ago, the57 said:

my drawing shows pins 3+4 are for the motor?

The wiring diagrams I have show 2 & 3 as the motor for the 1.6TDCI engine. It shows 3 & 4 as the motor for the 2.0TDCI engine.

It should be fairly easy to confirm this by measuring the motor resistance.

It does look like an open circuit in one of the motor drive lines, or as Ian suggests, a fuse. Though worth double checking that you were making good connections with the voltmeter probes.

But as both of the motor drive lines seem to be directly connected to the pcm, it is just possible that they are not energised while the engine is not running.

How are you making contact with the wires with the connector connected? Do you have a piggy back lead (pair of mating connectors)?  Or tee'd off the wires somehow? I ask because if F35 is ok, I would suggest monitoring pins 2 & 3 with the engine running, but you need a reasonably secure test connection for that.

 

[iantt]

thats strange, the wiring diagram im looking at both use pin 3 and 4 , the 2.0 tdci shows both going from pcm, but thev1.6 shows feed directly from fuse 35 and then other pin to pcm. mmm. will look on autodata and see what that shows.

[iantt]

derr, my fault. lol your right.

[iantt]

my excuse was im tired and trying to view wiring diagrams on small tablet. was looking at egr throttle actuator. just saw egr. opps.

[Tdci-Peter]

7 minutes ago, iantt said:

view wiring diagrams on small tablet.

Can't beat a 20 inch screen (or more) for looking at wiring diagrams! They are confusing at the best of times.

Given half a chance they turn into a mass of spaghetti, punctuated by incomprehensible symbols and inconsistent abbreviations. And I have drawn (and read) a few like that in my time!

 

 

[iantt]

 got the laptop out now. lol ,the various numbers and letters attached to the wiring diagrams give a good indication of what voltages or earths to expect, ie 30, 15, 7 31 most common, etc.

[the57]

still 0v disconnected and connected, i am back probing with tee pins, i'll have to check it again when its running, i should have 12v on one wire?

[Tdci-Peter]

1 hour ago, the57 said:

i should have 12v on one wire?

Yes, most likely there will be 12v on terminal 3, and some intermediate voltage on terminal 2. The drive signal is normally a pulse width modulated (PWM) square wave (12v & 0v), where the duty determines the average voltage to the motor.

It is just possible that 0v will be on terminal 2, and the PWM signal will be on terminal 3.

The signal wire is possibly more informative.

On my car (1.8) it stays at the closed value for a few seconds after start, then jumps up and hovers somewhere in the middle. Increasing the revs makes it change a bit, then releasing the throttle, it closes again briefly until the engine gets down to idle speed. On the 1.8, the pcm performs an EGR test on engine off, with a hover, a full open, then close & pcm shut down. I am not sure if the 1.6 does this.

I hope the drive voltages do appear, because otherwise it is either the wiring to the pcm, or the pcm itself, at fault.

But the code P042F suggests a functional problem with valve movement, or with the sensor signal. I would expect a different error if the drive signal was not present (at least at the pcm end).

 

[the57]

when i start the car i have 12v at terminal 3 for a few seconds then it drops to 0, set the code and the car goes lumpy, will there be 12v at terminal 2 

[Tdci-Peter]

4 hours ago, the57 said:

12v at terminal 3 for a few seconds then it drops to 0, set the code and the car goes lumpy, will there be 12v at terminal 2

It sounds like the EGR drive signal is getting through, but the sensor reading is not as expected, and the pcm is shutting it down.

I am not quite sure what "set the code" means, is that when the car sets the P042F code? Looks like the pcm is then reverse driving the EGR (12v on 2, 0v on 3), to force it closed. Consistent with the sensor voltage reading too high.

Peter.

 

[the57]

yes the car sets the p042f

 

[the57]

When the 12v goes off and the car goes lumpy is there something else that uses that 12v like the evap 

[Tdci-Peter]

31 minutes ago, the57 said:

When the 12v goes off and the car goes lumpy is there something else that uses that 12v

Those two lines (pins 2 & 3 on the EGR) are dedicated to the EGR. They go straight from pcm to EGR.

When the pcm sets the code, and reverse powers the EGR, it will go into a different operating mode, possibly a reduced power one.

You need to look at the sensor signal on pin 4, and the sensor ground on pin 5 & Vref (5v) on pin 1. The pcm is getting a different signal from the egr position indicator than it expects, and this is likely to be the cause of the problem.

Some possible causes:

Sensor  wire open circuit. (any of the 3).

Faulty sensor in EGR.

EGR stuck or blocked.

Throttle valve stuck open.

Intercooler bypass valve stuck open (if fitted).

 

[the57]

Pin1 5v good ref 

Pin2 2.65 bias voltage for about 8 seconds then 0.03

Pin3 0.15 engine off, engine running 12v for about 8 seconds then 0.03

Pin4 0.48 does not move 

Pin5 0.01 good ground 

Looking like 150 pounds which lasted 6 months, or an eBay one.

[Tdci-Peter]

5 hours ago, the57 said:

Pin4 0.48 does not move 

0.48v is reasonable for a valve closed signal. DTC says valve stuck, Pin4 says valve stuck.

These valves look easy to remove on this engine. I would take it off, and test it in comfort, on the bench. It could be an internal bad connection to the motor, so it does not operate. I have had that twice now (different places inside the valve) on my 1.8 EGR. Managed to dismantle the thing and fix it.

It could be the valve is mechanically stuck. It might free off and work for a bit, or work for longer if whatever is making it stick can be cleaned, sanded or filed off.

A multimeter can test its connections. A variable power supply would test its operation. Though it could just be powered with a battery charger, or even with a car battery (with great care against short circuits!). It probably needs between 2A & 5A to operate.

The fixed sensor voltage suggest the sensor part is ok, but it could be disconnected from the valve somehow (broken / misplaced link?)

One step forward, at least.

 

[akkilles]

Hi,

So what was end of the story? And what are finally correct voltages values?

[Tdci-Peter]

3 hours ago, akkilles said:

So what was end of the story? And what are finally correct voltages values?

The OP has not been back to the site since September 2016, so sadly we may never find the end of the story. That happens very often.

I would go with Ian's values for the Sensor:

Pin 1 = 5v ref, Pin 5 = 0v ground, Pin 4 = Signal: 1v closed, 4.2v open.

The motor drive voltages will be variable as they come from the ECU / PCM. Normal operating would be 12v on pin 3 while the valve is being driven open, with a lower (modulated) voltage on pin 2.

But Pin 3 may go to 0v while the valve is being driven closed, it looks like the ECU can power the motor in either direction.

It still seems like the valve on the OPs car was jammed shut, or the sensor was giving a wrong, fixed reading. The ECU tried to open it, but gave up and powered it down when the sensor reading did not respond, raising the DTC error code.

On the 1.6TDCI, it may be that the open and closed values stored in the ECU must be re-learnt if the valve is changed. A diagnostic system like Forscan can initiate this.

[yankee_1983]

On 8/17/2016 at 2:37 AM, Tdci-Peter said:

It could be an internal bad connection to the motor, so it does not operate. I have had that twice now (different places inside the valve) on my 1.8 EGR. Managed to dismantle the thing and fix it.

Hello, 

Can you tell which connection was bad? 

My EGR modul, Valeo, 1.6TDCi, non DPF, have broken in 2 years and 3 months or 35.000km after changing it.

I have tested it as following:

- the resistance between pins 2&3 is ~3.7Ohms. 

- when connected them to GND and 12V (directly to the motor after dismantling the head and the valve) nothing happens, just sparks. 

Does anyone knows what can cause breaking the egr modules?