ECU programming error on 2007 Citroen Dispatch? P0069 P0122

[Arlen]

Hi All,

First off, I'm new here but I've been driving and thoroughly enjoying French cars for 3 years, I'm also a trainee mechanic.

A good friend of mine bought a 2007 Citroen Dispatch 1.6HDi 90BHP (reg DA07EFU) several years ago as a rear-end write-off that was running fine. When he came to start bodywork on it, it wouldn't start, so another mechanic replaced the ECU in it and this got it running, but with issues that didn't exist before, P0069 and P0122, manifold pressure correlation with barometric pressure and throttle position sensor output too low.

I took on the van as a project about a month ago and I've replaced the MAP, MAF and TPS with genuine parts from other running and driving vehicles, this hasn't made any difference at all! I'm 99% certain it's not a wiring fault, if either of the sensors are unplugged then the error codes change from those listed above to "sensor 'x' open circuit", the ECU knows they're plugged in.

Where I got the idea that there's an ECU programming error is that I used an Autel MaxiSys ADAS (borrowed from work) to check the data stream from the TPS and MAP. The TPS is stuck at 0% and doesn't change regardless of pedal position (although the van will rev up to 2500 revs before it limits) and the MAP is stuck at 988mbar when the barometric pressure reading is 1000mbar and the reference value (which as I understand it is what the ECU expects to see from the sensor) is always between about 1015mbar and 1100mbar.

I've removed the outlet hose from the intercooler, there's a good strong flow of air coming through it from the turbo. I've also covered over the end of the inlet manifold with the engine running and the MAP sensor reading still remains the same, I'd expect to see some variation but still stuck at 988mbar.

My question is, with the information I've provided above, does anyone agree that it's probably an ECU programming error, and if so, can I just stick an ECU from a scrap van with the same engine into this one to test it or will the immobilizer need coding in etc?

Thanks everyone!

[ozvtr]

it wouldn't start, so another mechanic replaced the ECU in it and this got it running,

How did he go about doing that?

Do you still have the old ECU and any other electronic parts that "the other mechanic" replaced?

It seem a bit strange that "just sitting there" the old engine ECU failed?!

Yes, it's possible this other guy has installed the wrong ECU or it has not been initialized correctly. I'm not a "diesel guy" so hopefully someone will come along and say if/how the ECU can be initialized. Otherwise I would investigate why the original ECU decided to stop working. A least you know that the "old" set up did work and it cant be any harder than fault finding your current set up, which might prove to be incompatible!

You will need to supply the VIN and any details of the old and current engine ECUs.

[Arlen]

Thanks OzVTR,

The ECU was replaced 5 years ago, so the details are a bit foggy (yes, the van has been broken for 5 years, but it's been started and driven about once every 6 months during that time to keep everything else working) but as far as I know the original ECU did just fail seemingly without warning. Unfortunately, it's long gone, so I wouldn't be able to attempt to get the contents of it cloned into a new unit, however I can provide the VIN of the van if anyone needs it on here.

[wheeler]

To replace the ECU with a used one you would need to first send it to a specialist to either have the immo taken off (to make it plug & play) or have it virginised, it would then need matched back to the car using the security code.
The 3rd option would be to buy a second hand matched ECU, BSI & key kit. Just be aware though doing this means if the 'new' BSI has more miles on it than your van it will permanently write the higher mileage to your instrument panel.