Citroen Dispatch 2006 2.0 Hdi

[jradley]

Good morning,

The vehicle is a 2006 Citroen Dispatch 2.0 hdi with Bosch ecu. It went for its MOT and stopped running during the test. (not during the emissions test, just driving it onto the ramp). It has compression and runs on easy start but won’t fire up under its own power. The MIL light is off but the tank fuel pump is not running. I have swapped the fuel pump relay onto another vehicle, and it’s okay. The pump runs if I bridge it at the relay socket so I presume its a wiring issue. I have put it on a code reader and it won’t communicate, so I suspect it might be a supply issue to the ecu or possibly a problem with the link between ecu and relay. All fuses are intact. What I am struggling with is a pin out diagram for the ecu, it’s a 3 connector Bosch EDC 15, so I dont know which pins should be 12v.

Can anyone help with a pin diagram please?

Any other pointers appreciated.

Thanks

[wightdiag]

Two things spring to mind,

1) does it have an interia cut off switch possibly triggered by slamming into the MOT ramps

2) Does the MIL light up at ignition on then go out like it should - if it does you have a live ECU if not start with powers and grounds at the ECU

Dispatch 2 or 3

[valhalla]

If I remember correctly, around this sort of time, the Dispatch HDi pulls its own power-relay on from the Bosch ECU - I have fixed a couple of these, as the connector pin back into the ECU often fails at the header-joint, or around the connector, from vibration and heat-fatigue. Common "fix" is to add a jump-wire directly off the ECU and bring it out through the casing and past the connector plug, bridge straight into harness.

IIRC, the main relay control is a pull-down to ground by something like pin-5, or thereabouts. It is close to the front of the ECU as you stand in front of the van looking into the engine-bay on the driver's side, so it's on the first connector nearest the grille, and it's one of the first pins nearest you on that connector, bottom row IIRC.

It is well worth checking that the +batt is getting to the other side of the main relay (via the inertia switch?) - which as wightdiag suggests, is the very first thing to try.

[valhalla]

I have just checked Autodata, an it suggests that your ECU for the engine may be at the rear, nearside of the engine-bay? I am working on the assumption that you have a Dispatch II, but as wightdiag indicates, we would need to know.

The method of the HDi pulling its own main relay down to ground to switch itself on, still stands, as that is standard Bosch modus-oparandi, but the pinout might change according to the van series.

[jradley]

Many thanks for the responses.
The van is a Mk1, the ECU is mounted on the offside inner wing and the fuel pump relay on the nearside inner wing, next to the battery. I cant find an inertia cut off switch.
Picking up on wightdiag's comment the MIL light was on, then went out so the ECU must have power, so I have stripped the loom between the ecu and the fuel pump relay and found 4 wires that had chaffed on the inlet pipe support bracket. I have repaired them (soldered and heat shrink) and assumed that was the issue but I still dont have a working fuel pump.
The MIL light is now on and the ECU will now communicate with the scanner. It has 3 codes P0235, (intake sensor malfunction)? P0110, (Inlet air temp wrong signal) and P0230, (fuel pump low voltage).
I assume the later is why the pump isn't powering up?
What puzzles me at the moment is the van will most likely have stopped due to one problem, not several, repairing the 4 wires has put the MIL light on, confirming that at least one of the wires must have been either broken or shorted to earth. However the ECU is still saying there is a problem. (I did clear the codes and they came back so the faults are still current).
Ignoring P0235 and P0110 for the moment because I dont think they will stop the fuel pump running, I dont know what P0230 refers to. Is it the circuit that triggers the relay of the power supply across the relay? If I bridge the pins the pump runs, so I presume the latter is okay? If it refers to the triggering circuit, how does the ECU know that? Is it low voltage coming out of the ECU? Is this what you refer to valhalla?
Advice what to do next would be appreciated.

[wightdiag]

According to the data I have, you do have an inertia switch, usually in the footwell, small device with a rubber covered button on the top, press an hold down for a few seconds.

Look in the handbook under "fuel cut off" for the location. The switch cuts the ground to the fuel pump coil on the main relay R1  - pin 7, As you have power to the ECU and power to the pump when you jump it then the rest of that relay should be working, the pump obviously works as does the wiring to it.  

As to how the ECU knows - it expects to see B+ on the pump side of the relay, it doesn't then sets the code.

Surprised a code for fuel cut off is not set - that is the only thing that points away from it, check Power on Pin 1 which is the supply to the coil from the ECU - but the ECU needs to be powered up to supply it so you cant just pull the relay (if it is all one as per the dwg i have).

[valhalla]

It is definitely worth checking the output from the ECU - at the ECU - to the pump relay for its control. A short in the wiring could quite feasibly result in the failure of the control pin that I mentioned above. You should see  definite switch in voltage when the ignition is switched-on.

If you see no activity on the ECU control pin (you can look at the wire index number on the wiring into the pump relay, then relate that to the ECU harness), it would be worth disconnecting the ECU multiplug at that stage.

What I have seen in the past, and this goes back a few years, is that it was the action of "someone" pulling the ECU multiplug that did the final, fatal damage to the header connection in the ECU. It is not too difficult to pick-up the control signal at the header connection to the ECU-side of the pin, thin wire across the connector alongside it, then bridge it back into the control wire directly.

Look very carefully at the ECU connector pins once you have pulled the multiplug apart - more likely as not, you will see a break/corrosion/burning or even the male part of the connection left behind in the female pin.

[jradley]

Well, after almost 50 years of tinkering with vehicles of all sizes you have no idea how embarrassing it is to have to write this, but it has to be done. Hopefully others will learn from my mistake.


Started out last night by hunting in the footwells for the inertia switch, found nothing. Looked behind the glove box and up under the dash, still nothing, I had previously scoured the engine bay without any success, so continued on with the multi meter. Checked the battery voltage and then power to the relay, no volts at the relay. Bridged the relay again just to check that the pump still runs, and it did, so issue must be the no volts. Couldn’t work out how to find which wire at the ECU end fed the relay so went back to a circuit diagram I have in a little white handbook/workshop manual. It’s a bit blurry and very hard to read but tried before giving up. However in the same envelope was the proper drivers manual so whilst wondering what to do next I had a flick through with wightdiag's comments in mind and came across a page referring to the inertia switch. It’s a bit ambiguous but states the inertia switch is bolted to one of the suspension turret and its precise location varies from model to model, so I thought I had better check again. (The turrets on these vans are set back under the windscreen scuttle so not obvious). The nearside turret is fairly clear and there is nothing on that. The off side turret is obscured by wiper motor, power steering reservoir and some electrics. No inertia switch to be seen, but the power steering reservoir is slightly forward of the turret and hey presto, there behind it is a grubby orange inertia switch. I pressed the switch and everything springs back into life.

Dread to think how long its taken me to get to this point, and there is probably another 2 hours tonight putting it all back together.
No fool like and old fool springs to mind!


Thank you wightdiag and valhalla for your information and patience, without it I would still be floundering.

[wightdiag]

You are entirely welcome and glad you got it sorted. - Thanks for letting us know too!

[givusaclue]

Mar 8, 2022 9:45:01 GMT 1 jradley said:

Well, after almost 50 years of tinkering with vehicles of all sizes you have no idea how embarrassing it is to have to write this, but it has to be done. Hopefully others will learn from my mistake.


Started out last night by hunting in the footwells for the inertia switch, found nothing. Looked behind the glove box and up under the dash, still nothing, I had previously scoured the engine bay without any success, so continued on with the multi meter. Checked the battery voltage and then power to the relay, no volts at the relay. Bridged the relay again just to check that the pump still runs, and it did, so issue must be the no volts. Couldn’t work out how to find which wire at the ECU end fed the relay so went back to a circuit diagram I have in a little white handbook/workshop manual. It’s a bit blurry and very hard to read but tried before giving up. However in the same envelope was the proper drivers manual so whilst wondering what to do next I had a flick through with wightdiag's comments in mind and came across a page referring to the inertia switch. It’s a bit ambiguous but states the inertia switch is bolted to one of the suspension turret and its precise location varies from model to model, so I thought I had better check again. (The turrets on these vans are set back under the windscreen scuttle so not obvious). The nearside turret is fairly clear and there is nothing on that. The off side turret is obscured by wiper motor, power steering reservoir and some electrics. No inertia switch to be seen, but the power steering reservoir is slightly forward of the turret and hey presto, there behind it is a grubby orange inertia switch. I pressed the switch and everything springs back into life.

Dread to think how long its taken me to get to this point, and there is probably another 2 hours tonight putting it all back together.
No fool like and old fool springs to mind!


Thank you wightdiag and valhalla for your information and patience, without it I would still be floundering.

Takes a big person to publicly admit his oversights, well done & I’m sure that you will have learnt a valuable lesson from this, even if it’s only to avoid French vehicles 😂

Well done