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Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low - Fixed #

Posted by Shaun Dale on December 21, 2015, 7:35 pm

Year of Manufacture *: 2007
Engine Size and Code *: HHJA or HHJB
( Optional) Fault Codes: P0698 Seneor reference Voltage C circuit low.

Hi All,
Unfortunately I am not the first man in on this one, Customer has been playing "parts darts".
New cam and crank sensors, new MAF and EGR valve, no idea if genuine or not at the moment.
Vehicle stops with a P0698 code (hence the EGR valve as this appears a common cause).
My question is does anyone know where else reference voltage C is fed to? I found a fairly heavy chafe behind where the engine loom connects to the chassis loom but on inspection does not seem to have rubbed through to the copper. As access to the loom is poor round the back of the engine it would be nice to know geographically where the fault might lie and perhaps what wire colours are worthy of inspection.
Shaun

Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #

Posted by matt elliott <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1416' width='330' height='300' border=0 style='border:none;'> on January 26, 2016, 3:34 pm, in reply to "Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #"
Matt Elliott

Hi shaun did you get to the bottom of this one as we've the same issue here.

Thanks
Matt

Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #

Posted by Paul edge <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2887' width='330' height='300' border=0 style='border:none;'> on January 27, 2016, 12:49 pm, in reply to "Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #"

Hi shaun.had same problem on a 06 fiesta.after loads of testing I found water in a big square connector the back of the battery.it's held together by a 10am headed bolt....don't know if fusion has same plug
HTh paul

Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #

Posted by shayne walters <iframe src='https://members.boardhost.com/ukautotalk8/info/user=ukat3714' width='330' height='300' border=0 style='border:none;'> on February 7, 2016, 11:23 pm, in reply to "Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #"
Shayne Walters

If you want to test the wiring i would suggest pull ecu connections and from senosors egr etc and load test supply ,ground then the same to sensors supply and grounding wire .Good old volt drop test with a 21w bulb!! or I use a load pro on my meter.Then you can rule out wiring.

Regards
Shayne

Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #

Posted by Pere Roca <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5555' width='330' height='300' border=0 style='border:none;'> on February 8, 2016, 9:43 am, in reply to "Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #"
Pere Roca

p0698 is refered to 5v. feed to several sensors:
fuel pressure sensor
EGR position sensor
a/c pressure sensor
Engine stops because ECU don't "know" wich is the fuel pressure value, poor strategy I think...
The EGR position sensor is the most common cause of this fault, but it can be a wiring fault and very hard to find... Regards.

Fixed #

Posted by Shaun Dale on March 30, 2016, 1:20 pm, in reply to "Re: Ford Fusion TDCI 2007 - Code P0698 sensor reference voltage C circuit low #"
Edited by board administrator March 30, 2016, 2:01 pm

Apologies for not popping in and reporting the fix earlier.
In this instance it was the fuel rail pressure sensor. On bench test the supply current draw varied between 45 and 180mA as it felt like it!
Only available as part of the complete fuel rail from Ford. I bought one on Ebay from newpartautomotive for £25. on close inspection the quality proved to be very good and googling the makers name proved to be from a very large sensor manufacturer so I was happy to fit it (always wary about Ebay stuff). The car worked fine afterwards.
Shaun.

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