Hi all

Never found myself having to create a topic before but I'm out of options and need some ideas.

To cut a very long story somewhat short whilst giving as much detail as possible:

I have a 2019 Fiesta ST, pre-2019 engine design change (this may or may not be relevant). Knackered the engine so replaced with one of the later design. Replacement engine came with gearbox so swapped the lot (new one has LSD, original did not).

After swap, car started on first spark. Seemed to run flawlessly. Drove for an hour or so and the engine cut out when accelerating, throwing EML and spanner light with "see manual". It didn't want to immediately restart, but after switching ignition off, opening and closing the door, it restarted. EML and spanner remained. 

Drove it for a day or two and borrowed a cheap diag tool. Read CKP sensor fault - P0335. Code cleared, EML extinguished. Maybe a hiccup. (Nope)

Later on, spanner light came on without EML. Left the car for a bit, came back and all fine again.

Getting to the point, 2 days after the swap, in nearly identical conditions as before, i.e. accelerating in third gear and around 4-5krpm: EML, spanner, and cutout. Car does not restart. Since borrowed a Launch diag tool which read around 9 codes initially, 3 of which remain after clearing. 

 

DTCs with exact text (active in bold) :

P0124: Throttle/Pedal Position Sensor/Switch 'A' Circuit Intermittent

P0237: Turbocharger/Supercharger Boost Sensor 'A' Circuit Low

P0335: Crankshaft Position Sensor 'A' Circuit

P033F: Crankshaft/Camshaft Loss of Synchronization 

P06A8: Sensor Reference Voltage 'C' Cicuit Range/Performance

P08A9: Clutch Pedal Position Sensor 'A' Circuit Low

P08B6: Clutch Pedal Position Sensor 'B' Circuit Low

P26C3: Internal Control Module Transmission Range Sensor Performance

U210F: Throttle/Pedal Position Sensor/Switch 'A' Communication Circuit Low

 

Both P0335 and P033F are no longer present and seem to have been replaced with P01BC: Engine Oil Temperature 'B' Circuit High.

Initially, it made sense that a CKP sensor issue would cause all sorts of problems, including shutdown. Now that code is not present, it would seem that clutch pedal position sensor is inhibiting start, also given the prompt on the cluster is now "press clutch and brake to start". The engine will crank if you want it to by holding the start button, but really does not want to start. Furthermore, live data suggests that the clutch pedal switch is reading 0V and 0% depression, along with a status of "Clutch Partly Pressed", none of which change when pressing the clutch. However, with ignition switched off, the clutch pedal switch audibly activates the exhaust valve actuator, so there must be some signal to it?

We've checked all visible connectors and accessible parts of the harness and nothing appears to be disconnected or out of place.

Considering all DTCs as a whole, I would guess it's some sort of power supply issue (harness, connector, earth, PCM itself etc) but that still leaves a lot to narrow down. I've contacted a number of ECU testers, all of whom seem to be unable to test my particular unit (the original). I've also been advised that it shouldn't be a programming issue as it shouldn't be necessary. Might be an option to clone my unit to a second hand one if it comes to that. Our electrical knowledge requires development, to say the least, so I thought I'd post here to see if any genius out there could possibly crack the code from a wall of text. 

 

Cheers!

 

 

 

First thing you need to is read the DTC's using Ford specific software. Generic code readers even expensive ones, very often fail to read the Ford specific codes, and/or make errors with the explanations they present.

In the absence of the Ford main dealer equipment then the best alternative is to use FORScan, together with a windows based laptop.

On 4/7/2024 at 8:59 PM, unofix said:

FORScan (for use with Windows Laptop) : https://forscan.org/download.html

It's what many Ford owners use including some Ford technicians.

• vLinker FS, cable for laptop: https://www.amazon.co.uk/Vgate-vLinker-Adapter-FORScan-MS-CAN/dp/B0952P4MLP

OR

• OBDLINK EX, cable for laptop: https://www.amazon.co.uk/OBDLINK-EX-FORScan-OBD-Adapter/dp/B081VQVD3F/ref=sr_1_5

 

• vLinker FD, for android phone: https://www.amazon.co.uk/Vgate-Bluetooth-vLinker-Scanner-Diagnostic/dp/B08H82WC8L
• vLinker FD+, for iPhone: https://www.amazon.co.uk/Vgate-Bluetooth-vLinker-Scanner-Diagnostic/dp/B08H8JHWP2

 

Search Tag:   FORScan123

 

Thanks unofix,

I've been able to see the codes on FDRS, I'm not sure how reliable it is but it's showing the same codes

 

I'll be definitely looking into FORScan though, cheers.

 

I would say, but I could be wrong, that you would also need (at least) the PCM software from the donor car or the PCM itself

I reckon your original PCM does not like the new set up

1 hour ago, DaveT70 said:

I would say, but I could be wrong, that you would also need (at least) the PCM software from the donor car or the PCM itself

I reckon your original PCM does not like the new set up

Thanks Dave,

This is something I have considered, but unfortunately the donor PCM is not available. Would a reflash of my unit have a similar effect?

40 minutes ago, sadhorse said:

Would a reflash of my unit have a similar effect?

You could try

45 minutes ago, DaveT70 said:

You could try

Wouldnt the PCM for replacement engine be required to harvest the info to flash it to his own one ? I dont know how they would know what info to program into it without it. Or am i being thick ? dont answer that lol.

You'd need the VIN of the donor car so it can be downloaded

After reading deeper:

Or your ABS module or CCM does not like the gearbox as your current modules (and cluster software - IPC) does not have performance pack software

5 hours ago, DaveT70 said:

After reading deeper:

Or your ABS module or CCM does not like the gearbox as your current modules (and cluster software - IPC) does not have performance pack software

Stupid question then, how would it 'know' that the gearbox is different?

I haven't got forscan yet, been doing some research... would it be able to address that if it is the issue?