Hi all.

I have had this Touran in a couple of times with this problem. The first time it came in, it was a non start with the fault code 16705 (P0321) Engine Speed Sensor (G28): Implausible Signal. I scoped the crank/engine speed sensor. No output signal. So I replaced the crank sensor (after removing the oil filter assembly to gain access to it). After fitting the sensor the vehicle still did not want to start straight away. It eventually started but a bit lumpy for about 30 seconds but then was fine and started on the button every time.

The customer had the vehicle back for the weekend and came to start in on the Monday morning and it started but would not rev out. We recovered it and check for codes. No codes but it would only just idle and not rev out at all.
We checked the fitment and wiring to the crank sensor. All seemed ok. Knowing that the inlet flaps and EGR valve get stuck on these, we removed both and cleaned them up. Although they looked in serviceable condition. We refitted them and it started first time no problems.

Customer had vehicle back once more and by the Monday morning it did not start again! This time it just cranked and did not start. The glow plug light on the dash was flashing. Rechecked for codes. 16705 (P0321) Engine Speed Sensor (G28): Implausible Signal was back! I re-scoped the crank sensor. All ok. So the next step was to check the cam sensor. I disconnected the sensor to check the connection. All was ok. I thought I would just crank it to see if anything would happen and after a second or 2 it fired up and ran fine. I reconnected the sensor and the vehicle cut out. I scoped the cam sensor and the signal was poor. So I replaced the cam sensor and checked the valve timing , which was spot on. Tried to start the vehicle and it did not go with the sensor connected. Disconnect it and away it goes!!
This morning I had another look at it with a clear head! Went back and checked the connection to the crank sensor. Still ok as far as I can see. Tried to start it with everything connected. Did not want to start. Just cranked and cranked. Disconnected the cam senor. Started in a couple of seconds. Reconnected the cam sensor and tried again. Started on the button and ran fine. Starts and runs every time but I have not really fixed anything!!

So I just need any ideas of where to start looking now! I do not have a wiring diagram for this exact engine code so I have not been able to check the wiring from the sensor to the ECM.

Any help would be really appreciated – Thanks!