Bosch VP30 VP44 injection pump repair solution

**stevebbb** · 24th May, 2018, 08:22 PM

**dynasat** · 26th May, 2018, 11:51 PM

Thanks stevebbb, much appreciated!

May I ask how you worked this out? Do you have a schematic diagram, or have you made your own measurements?

**dynasat** · 29th May, 2018, 04:17 AM

I measure these points as connected in blue:

PSG_board_pad_2.jpg

I believe these are the source (-ve) connection.
I need a connection to the small pad above in red for the drain. Am I looking at this somehow wrong?

**stevebbb** · 29th May, 2018, 07:02 AM

PSG_board_pad_2.jpg

sorry for the mistake...

**dynasat** · 2nd June, 2018, 03:31 AM

Thanks stevebbb for the correction.

Despite being an electronics engineer, I'm struggling to solder to these virtually microscopic components and pads. Do you happen to know whether there's anything else connected to this node between the drain and capacitor?

I think I made a mistake trying to do this leaving the unit in the car. I'm contemplating instead soldering a 1nF capacitor between the source and drain, but wondering if there's anything else connected here, or whether this point may be involved with the PSG pin 5 MAB signal feedback to the ECU.

I'm getting close to the point of throwing in the towel and buying a new pump.

**stevebbb** · 3rd June, 2018, 09:48 PM

I think it's just a capacitor to ground, nothing else connected.

**geekshow2** · 12th July, 2018, 12:20 AM

Hi all, I have a dead short on pins 6 & 7 (Gnd and +12v) on my Transit Connect's VP30. Could the fault still lie with the transistor? I have 2 IRLR2905 sitting waiting here. No visual indications anything else has gone...
kp_VP30_dead_short.jpg

**TR0UBLESH00TER** · 12th July, 2018, 07:10 AM

If this photo is the real unit and there is a short between 6 and 7 then transistor is out of the question ,maybe 5 volts regulator which is on the next corner ( reverse clock counting ) .Or you can use a regulated voltage supply and inject 1,2 or more amps and watch for heating components ,maybe a cap is shorted ...

**geekshow2** · 12th July, 2018, 02:43 PM

Originally Posted by TR0UBLESH00TER

If this photo is the real unit and there is a short between 6 and 7 then transistor is out of the question ,maybe 5 volts regulator which is on the next corner ( reverse clock counting ) .Or you can use a regulated voltage supply and inject 1,2 or more amps and watch for heating components ,maybe a cap is shorted ...

Thanks Tr0ublesh00ter, I followed the 'repair vp 44 pump' guide and found the 5v regulator also to be faulty (dead short +12v to ground). That's out of the circuit now, but there's still only <1k resistance between +12v and ground, and I seem to see a dead short between +5v and ground. I suspect you're right, and a downstream cap has failed. At this rate, it's maybe not worth fixing, but at least I'm learning....

The photo is my actual unit, yes.

Update: I've just removed every component with a short off the board and there's still a dead short on the 5V line. I think it's dead :-(