So... I've a 2006 smax 127k miles

I've had a few gremlins one of which was a faulty fuel filter housing.. replaced so now no more air.

Car runs / starts on easystart/brake cleaner but will not start and run under its own fuel.

 

Snapon Ethos Edge scanner threw me a few errors so I thought okay easy fix.

 

P0336-31 Crankshaft position sensor "A" Circuit Range/Performance

Changed sensor and pickup ring to be sure. Checked timing whilst at it and engine is 100% in time.

Still no start. 

 

Also 2 other codes.. one of which is understandable (P0562-00 - System Voltage Low) due to low power battery

 

The next code is sending me in circles..

P0A09-00 Dc/Dc converter fault circuit low.

 

Either way I cannot get this engine to just fire up again. Any ideas of where to start looking and the potential culprit of this problem may be.?

Edited June 26, 2025Jun 26 by DusteeS9
Photo upload

Welcome!

Battery issues, age? - charge/test/replace?
Any other relevant history i.e. sorting the air leak has caused a crank sensor error???

Electrical issue/damage between crank sensor and PCM (has signal been checked all the way back?) Is there anything on crank/cam/correlation in Forscan live data or on your scanner?

Assume fuel system is fully primed after housing change (been there, done that) but if there's no crank signal it may not make a difference yet?

May need to find a way to see if injectors are triggering but again, if there's no crank/cam correlation they are likely switched off?

DC/DC converter (if I knew what it was, where it was, why it is needed that would be great!- more relevant to hybrid/electric?) MAY again be caused by low voltage.

SO, I'd start with getting the low voltage/battery issue sorted, check the crank sensor issue - even new sensors can fail so getting a signal at the sensor then tracing it back to PCM, second priority.

Clear the codes, see what comes back, report.

Hopefully someone else can confirm or otherwise...

So in regards to ths Voltage.. the battery was fully charged and tested okay, didnt have low power issue but DC/DC still came up.

I also belive its a petrol hybrid error so why its reading on this ive no idea.

I've not been able to forscan as ive misplaced my cable! And haven't yet fully got mg head around the Ethos Edge system so a little learning on the fly is needed here.

One thing to note is when I changed the crank sensor ring (original appeared damaged) the replacement is a thin plate in comparison.  A little digging tells me the original was different and commonly failed so was redesigned which meant replacing with a new pickup ring and then the new cam pully that had the offset fitment to compensate the different thicks fitting.

Also now ths notches on the ring are different so unsure if its relevant. But its very much the part number supplied by ford for the car.

Is there perhaps a method of re-learning crank / cam correlation.? 

 

Visually ive checked the harness and all appears well, connections pins etc all seem good..

If you are certain about the battery, I'd clear the codes and see what comes back.(need to get rid of any possible voltage related codes?
Crank/cam correlation can't be relearned, I believe there is a signal measured from each sensor and if they make sense, everything follows.
Since you've changed the sensor and ring (how did the damage happen?) i looks like that could be the source of the problem needing a signal to be determined (all the way to PCM but at the sensor would be a start.
Again, is there nothing in your scanner to indicate correlation or signal presence?

I've just put the battery on an overnight charge so I'll assess that again tomorrow. Now I only have two codes and that's the low voltage and again the DcDc converter.

According to the scan there's no other faults. All codes cleared them 2 remain car cranks but again no start.

Same when being jump started still nothing with additional power. 

Will see what happens when I reconnect the battery tomorrow.

The sensor had a small chunk missing on the tip and the ring had some damage to the magnet around the outer edge so my guess is something has flicked up and got snagged. This is also why I was inclined to check the timing incase something untowards had happened but the engine is still 100% in time.

I've just read about someone having the DC/DC Converter error on the same engine in a mondy mk4 and turned out to be because of a bad glow plug.. but im feeling that's not my issue as when ive got it to turn over. It doesn't continue to run on its own fuel system

Firstly you need to be using Ford specific diagnostic software and not an all purpose generic code reader like SnapOn.

If the engine will start on 'easy start' or 'brake cleaner' and once started it runs fine, then you can rule out Crankshaft position sensor, or in fact any other timing issue. This is always the danger of reading codes with generic devices.

You possibly have two problems going on at the same time. (1) The battery State Of Charge is low. This is causing the cranking speed below the ideal, and is making it harder to start. (2) You have a fuel related problem. This could be a simple as there is still air in the fuel lines, or you have a problem with the HP pump.

Actions:

First either replace the battery with a new one or charge your existing battery. Make sure to charge it for 12 hours before fitting.

Next use FORScan, and check for Ford specific DTC's. Monitor in particular, the cranking speed, the fuel rail pressure.

 

Of course, as said if it starts on Easy Start timing (Edit: but not necessarily signals cos the fuel isn't coming from the car?) OK. 🫡

I know we rate Forscan not cheap generic OBD readers (obviously very limited) but if the likes of Snap On Autel, Topdon etc aren't able to have the ability to do checks on correlation and read live data from manufacturer specific PIDs for multiple makes, it's a very poor show (considering they can cost thousands)?

19 minutes ago, Shearers said:

but if the likes of Snap On Autel, Topdon

To be honest the only generic DTC reader that I would use is SnapOn. Having said that, it still has limitations.

Topdon and Carly, are both poor, and very expensive and not something I would ever use.

Autel, is very hit and miss. Sometimes it will read DTC's well and other times not. It often seems to depend on the model and age of the vehicle.

FORScan is effectively free, yes you need to buy a connecting cable or a dongle, but after that your good to go !

I have just ordered a replacement cable for forscan which is due tomorrow so hopefully with a full battery tomorrow will bring me a little closer to finding some answers 👌

So.. overnight I charged the battery this Changed nothing. Even fitted a good working battery and still the same.

I'm not longer getting crank sensor related faults but this low voltage and Dc/Dc converter fault are lingering predominantly

 

By process of elimination; I dont suspect the starter or alternator because the car will and does run just not on its own fuel.

As for reading live data for fuel / various sensors etc im new to that element of things so its not something im overly sure on how to do or accurately if I do figure it out..

 

Either way it seems to be electrical/signal related causing the car to not run on its own fuel system

Am I looking at a possible PCM fault itself.?

3 hours ago, DusteeS9 said:

Am I looking at a possible PCM fault

Possibly, but more likely damaged or corroded wiring to the Powertrain Control Module. The connectors are prone to corrosion and the actual wiring harness is usually a bit short which results in it rubbing against brackets etc. and causing damage.

Do you have any 'jump leads' ?

If yes, then just use one of them and connect it between the battery negative terminal and a good solid bit of metal on the engine (or gearbox), and then try and start the car.

28 minutes ago, unofix said:

Possibly, but more likely damaged or corroded wiring to the Powertrain Control Module. The connectors are prone to corrosion and the actual wiring harness is usually a bit short which results in it rubbing against brackets etc. and causing damage.

Do you have any 'jump leads' ?

If yes, then just use one of them and connect it between the battery negative terminal and a good solid bit of metal on the engine (or gearbox), and then try and start the car.

Wouldn't doing this be a similar effect to jump starting from another car.. which I've also tried with no success.

No.

Because if you have a poor earth connection between the battery negative and the engine then it is not the same as trying to jump start from another vehicle.

13 hours ago, unofix said:

No.

Because if you have a poor earth connection between the battery negative and the engine then it is not the same as trying to jump start from another vehicle.

I actually overlooked this massively! I'll give it a shot later/tomorrow and come back with that i find.. although wouldn't a bad ground also not allow it to start on easy start?

On 6/27/2025 at 11:02 PM, unofix said:

No.

Because if you have a poor earth connection between the battery negative and the engine then it is not the same as trying to jump start from another vehicle.

So tried as you suggested.. grounded battery direct to various good contact points on both the engine and gearbox each time with zero success. Battery voltage is fine, car is cranking fast enough but still will not start. Again started on brake cleaner but cuts out straight after as it still will not run on it's own fuel system which to me indicates the injectors may not be firing

1 minute ago, DusteeS9 said:

but cuts out straight after as it still will not run on it's own fuel system which to me indicates the injectors may not be firing

What does FORScan say ?

@Tizer will be able to recommend what PID's to monitor.

8 minutes ago, unofix said:

What does FORScan say ?

@Tizer will be able to recommend what PID's to monitor.

I've still the same 2 faults.. low voltage and dc/dc converter fail.. I'm currently just trying to learn how I read fuel pressure/requirements etc as that side of things (ie live data) is very much new to me

2 hours ago, unofix said:

What does FORScan say ?

@Tizer will be able to recommend what PID's to monitor.

Crankshaft sensor fault has returned.. swapped with a 2nd new sensor and fault still appears. Trying to run fuel pressure live data and simply nothing happens there's no data reading whatsoever 

Reading fuel rail pressure through Ethos @unofix

@DusteeS9 If you go into Live Data in the PCM and bring up RPM and any Fuel Ones, you can use the Search Function in FORScan. If there is no reading from the Crankshaft Sensor there will be no RPM reading while Cranking and the PCM will not command the Injectors to open. 

Here is the official FORScan guide, it is a bit difficult to follow but you should get there.  FORScan documentation v1.3.x

On 6/29/2025 at 9:50 PM, Tizer said:

@DusteeS9 If you go into Live Data in the PCM and bring up RPM and any Fuel Ones, you can use the Search Function in FORScan. If there is no reading from the Crankshaft Sensor there will be no RPM reading while Cranking and the PCM will not command the Injectors to open. 

Here is the official FORScan guide, it is a bit difficult to follow but you should get there.  FORScan documentation v1.3.x

So a little further digging.. my crank sensor 5v pin reads 5v .. the signal pin is 0.2v whilst ignition is on

Does anyone happen to have a wiring diagram for the engine wiring harness.? Struggling to find one for reference

Sorry the oldest S-Max schematics I have is for the 2013 model.

2 minutes ago, unofix said:

Sorry the oldest S-Max schematics I have is for the 2013 model.

Could I see this please as parts of loom will be the same as some of the sensors fit both pre and face-lift models 🙌👍

On my Google drive for download:

https://drive.google.com/file/d/1a0RfFRCXPd2_12_3zGp-ouGab2t-WOxW/view?usp=drive_link