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VIVARO 2.0 CRANK SENSOR SIGNAL PROBLEM

6K views 8 replies 3 participants last post by  AJ08 
#1 ·
Hi all,

I'm currently having an issue with my 2008 Vivaro 2.0 M9R which is now no-start. I'm now at a loss and looking for some help / info and would be greatly appreciated.

So.… from the beginning...

The van is only showing 1 fault code 'DF120 Engine Speed Sensor Signal', when deleted it comes straight back on upon cranking.

I have fitted a new sensor 'non original' and still no joy... upon reading up on several forums I opted to dive in and replace the timing chain + tensioner with an original Renault kit. Upon removing the old chain it was obvious the it had stretched and I couldn't even fit the timing tool onto the exhaust / inlet cam. New chain on and timed everything up, cranked over by hand and re-checked timing (did this 4-5 times for peace of mind) finally got the timing cover + engine mount back on, turned the key and.... no start and same fault code showing!

Went back to the drawing board and decided to remove CKS and pull the loom back to the ECU, checked with the wiring diagram and checked both wires on the X51 plug (A3+A4 IIRC) both wires confirmed to be good. I then checked the sensor itself and was showing 700 ohm, happy enough with this. Now this is where I though I finally found the issue I was having all along... I connected the CKS into the harness in the loom and tested A4 +A3 pins on the X51 ECU plug and was showing nothing on the muti-meter but with a little wiggle and slight pressure on the connector it then gave me the 700 ohm I was seeing when testing just the CKS. Finally I thought progress was being made.... due to the connector spades on the plug being to 'loose' it wasn't making a solid connection to the sensor, I then tried a very temp fix (just to see if I could hear it run finally) I put a few solder drops on each sensor pin to essentially make the pins bigger for the plug to grip onto. Re-fitted sensor and connected loom, checked resistance over A4+A3 again, still showing 700 ohm (looking good!) re-fitted ECU and went to turn the key.... Just cranking and same fault code!! Now I'm really scratching my head :confused:

Pulled connector on CKS again, multi-meter on both pins of CKS and cranked over, showing a nice 1.8v. I've had a look into the block hole where sensor sits and teeth look good on the pick-up ring.

If you've made it this far then I thank you, I know it's a lot of info but surely the more info the better.

ANY SUGGESTIONS??
 
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#3 ·
Thanks for the reply.

Yes I’m confident that it is fully home, greased up the o-ring and worked it most of the way by hand then used the 8mm bolt to take it the rest of the way. Feels flush with my finger... I’m away to try a genuine sensor, for the sake of £45 just to rule it out.

I’ve not tried easy start on it, will do this in the morning as she is now on charge tonight. If she fires up on easy start what would your next step be? Like I say, new genuine sensor will be fitted tomorrow.
 
#9 ·
Yeh my bad. Got called away with work then lost interest and now with all this going on.

So.... update time

I’ve carried out a compression test and all cylinders are low (approx 12 bar across all 4 cylinders), during cranking it just doesn’t seem like it’s getting enough speed so I’ve plugged in my scanner and it’s showing an unhealthy 140 -150 rpm during cranking process (probably why I’m getting this fault code from the get go), I thought I would be as well try a new battery and starter motor just to see if that made any difference (cranking speed improved slightly but still around the 170 rpm mark)

Any suggestions to why it’s cranking so slow?
 
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