Hi all, first time posting on here but I've read so many posts, often with info missing or people have jsut stopped posting part way through so who knows how the problem was solved, so I've decided to give the best account of what I'd done to solve the above problem. I was expecting to have this solved today but I'm still waitng for a delivery, which will be my next step. Anyway, make a brew and read on.
The subject fault was mentioned to the garage when the van went to for MOT. They changed the Glow Plugs, £350, as that is what their fault reader suggested. On collecting the van, started it up, drove it 20 metres down the road and the warning lights came on again. Back into the garage and they said it will be a NOX sensor but I’d have to book it in. This was in December last year. With too much going on I decided to leave it temporarily as it had no effect on performance.
Moving on a handful of weeks I connected my fault reader which gave:
Adblue Dosing Module Computer: Missing Message. Not sure what this meant so visited lots of forums and watched numerous videos, which provided plenty of useful and not so useful info.
So are with my fault reader looked into DPF faults but soot level was very low like it had recently carried out a Regeneration. This it must have done of its own accord as I’ve never considered a forced regeneration.
Next, the Upstream Turbine Pressure wasn’t reacting with increases in engine RPM – this from looking at Live Data on the reader. Thanks to O’Riley’s Autos I discovered how to clean the Upstream Turbine Pressure pipe, this I carried out, ran live data again and the pressure was reactive to engine speed proving the Upstream Turbine Pressure sensor was working, so no need to replace that.
Another suggestion was the ambient temperature sensor, now although the temperature was displayed on the van dashboard, I did on a couple of occasions get an ambient temperature fault for the Injection System, so I ordered another driver’s mirror, this came, by which time I was only half convinced that this was at least a part of the problem. So cleared all faults and dashboard warnings, unplugged original mirror, dashboard warnings came back on along with the original fault and other engine management faults. Plugged in the new mirror, reset faults and original Adblue Dosing Module Computer: Missing Message returned. So pretty sure the temperature sensor is not at fault.
Next, Adblue Crystallisation, in the tank or in the injector. I’d seen articles about this a couple of weeks prior and had bought some Wynn's Crystal Clean & Protect Car AdBlue Preventative Crystallisation Cleaner Additive, then added it to the Adblue tank. So when I checked the Adblue injector and the exhaust mounting face they were clean as a whistle – no crystallisation whatsoever. Maybe or maybe not the result of the additive.
Live data run again, (after more videos and reading), to check the Adblue Injector, NOX Upstream and Downstream sensors, these read 0% adblue being injected and 0ppm being sensed in both NOX sensors. Okay, perculiar, what’s common to all these three items, Adblue Dosing Module Computer which lives under a panel under the driver’s seat. So removed that, cleared faults and disconnected the plug. Adblue Dosing Module Computer: Missing Message returned along with DPF sytem warning on dash but no additional faults. Considered this for a while, found someone local, 20 miles away, who was selling one, bought it but he insisted on posting and didn’t want me to collect. I’m now still waiting for this to be delivered after he advertised 2 day delivery, this is day 3. It’s still an outside chance this may cure the problem.
So amongst other jobs on the van, over the last couple of days I’ve been looking at the NOX sensors. After making some wooden ramps I’ve had the van raised which has allowed easier access to find the NOX sensors but more importantly the wiring connectors. There really is little diagrammatic info on the exhaust and Adblue systems so I invested in the online Haynes manual.
Now as someone who used physical Haynes manuals in days of old I was expecting a modern day version of that, ‘based on a complete strip down and rebuild’ was one of their straplines. No forget that, absolutely useless unless I wanted to see pictures of a Mercedes GLA being jacked up, some other car’s brakes being worked on or I wanted to remove the whole engine and gearbox with all the special tools and supports required. Not even a schematic wiring diagram, very few Renault Trafic specific photos but many abstract diagrams. Complained and requested a full refund.
Where was I? Nox sensors. Located the rear sensor and ecu, all wiring looked intact. Clerared diagnostic faults again disconnected plug and checked faults. 2x Dosing Module faults. Reconnected plug, cleared faults and checked again, 2nd fault has cleared, so assume rear/downstream Nx Sensor is functioning.
Now to the front/upstream NOX sensor. This is opposite the Adblue injector, followed cable but couldn’t see the connector and ecu. Eventually after much shuffling under the van I managed to get eyes on it, this was followed by the use of many colourful adjectives before the connector eventually came off. Checked codes again, No difference still the single Adblue Dosing Module fault. From this I put my expectation on this NOX sensor not functioning correctly.
Now there was a video of a NOX sensor being removed but not disconnected from a Mercedes GLC, the owner then cleaned the sensing end of the sensor overnight in diesel fuel additive on the basis that this supposedly removes carbon from injectors etc, therefore in concentrated form it should do the same to any present in the NOX sensor. Taking this as a next step before ordering a replacement sensor I attempted to unscrew the sensor. It wasn’t shifting with my large adjustable (this wasn’t slipping either) so I ordered a recommended, from another video, 22mm NOX sensor removal crow’s foot. Due to be delivered in a day or two. Meanwhile I recalled a piece of hand railing was languishing in the shed, eventually finding this 3ft tube I manage to get it onto the adjustable and it loosened the sensor first go. It needs to be said that I had soaked the sensor in penetrating fluid a couple of hours earlier expecting it to be soaking for a couple of days until the crow’s foot arrived.
Soaked overnight in diesel additive, then sprayed with brake cleaner to hopefully remove any loosened debris, it was refitted. Did a fault scan on the reader and this didn’t solve the problem, still the same fault as when I started. Dive a live scan whilst out driving with a co-pilot to monitor readings of course and saw:
Upstream NOX 0%
Downstream NOX varying from 10 % to 190%+ with engine load and speed
Adblue injector once warm might spray anything up to 25%, but only sporadically and not in line with any engine load or speed.
So next step is to wait for replacement dosing module to arrive, install that. If unsuccessful, then it will be a replacement Upstream NOX sensor.
Sorry to be long winded but I wanted to provide as much info as possible.
Hopefully the solution will follow sooner rather than later.
The subject fault was mentioned to the garage when the van went to for MOT. They changed the Glow Plugs, £350, as that is what their fault reader suggested. On collecting the van, started it up, drove it 20 metres down the road and the warning lights came on again. Back into the garage and they said it will be a NOX sensor but I’d have to book it in. This was in December last year. With too much going on I decided to leave it temporarily as it had no effect on performance.
Moving on a handful of weeks I connected my fault reader which gave:
Adblue Dosing Module Computer: Missing Message. Not sure what this meant so visited lots of forums and watched numerous videos, which provided plenty of useful and not so useful info.
So are with my fault reader looked into DPF faults but soot level was very low like it had recently carried out a Regeneration. This it must have done of its own accord as I’ve never considered a forced regeneration.
Next, the Upstream Turbine Pressure wasn’t reacting with increases in engine RPM – this from looking at Live Data on the reader. Thanks to O’Riley’s Autos I discovered how to clean the Upstream Turbine Pressure pipe, this I carried out, ran live data again and the pressure was reactive to engine speed proving the Upstream Turbine Pressure sensor was working, so no need to replace that.
Another suggestion was the ambient temperature sensor, now although the temperature was displayed on the van dashboard, I did on a couple of occasions get an ambient temperature fault for the Injection System, so I ordered another driver’s mirror, this came, by which time I was only half convinced that this was at least a part of the problem. So cleared all faults and dashboard warnings, unplugged original mirror, dashboard warnings came back on along with the original fault and other engine management faults. Plugged in the new mirror, reset faults and original Adblue Dosing Module Computer: Missing Message returned. So pretty sure the temperature sensor is not at fault.
Next, Adblue Crystallisation, in the tank or in the injector. I’d seen articles about this a couple of weeks prior and had bought some Wynn's Crystal Clean & Protect Car AdBlue Preventative Crystallisation Cleaner Additive, then added it to the Adblue tank. So when I checked the Adblue injector and the exhaust mounting face they were clean as a whistle – no crystallisation whatsoever. Maybe or maybe not the result of the additive.
Live data run again, (after more videos and reading), to check the Adblue Injector, NOX Upstream and Downstream sensors, these read 0% adblue being injected and 0ppm being sensed in both NOX sensors. Okay, perculiar, what’s common to all these three items, Adblue Dosing Module Computer which lives under a panel under the driver’s seat. So removed that, cleared faults and disconnected the plug. Adblue Dosing Module Computer: Missing Message returned along with DPF sytem warning on dash but no additional faults. Considered this for a while, found someone local, 20 miles away, who was selling one, bought it but he insisted on posting and didn’t want me to collect. I’m now still waiting for this to be delivered after he advertised 2 day delivery, this is day 3. It’s still an outside chance this may cure the problem.
So amongst other jobs on the van, over the last couple of days I’ve been looking at the NOX sensors. After making some wooden ramps I’ve had the van raised which has allowed easier access to find the NOX sensors but more importantly the wiring connectors. There really is little diagrammatic info on the exhaust and Adblue systems so I invested in the online Haynes manual.
Now as someone who used physical Haynes manuals in days of old I was expecting a modern day version of that, ‘based on a complete strip down and rebuild’ was one of their straplines. No forget that, absolutely useless unless I wanted to see pictures of a Mercedes GLA being jacked up, some other car’s brakes being worked on or I wanted to remove the whole engine and gearbox with all the special tools and supports required. Not even a schematic wiring diagram, very few Renault Trafic specific photos but many abstract diagrams. Complained and requested a full refund.
Where was I? Nox sensors. Located the rear sensor and ecu, all wiring looked intact. Clerared diagnostic faults again disconnected plug and checked faults. 2x Dosing Module faults. Reconnected plug, cleared faults and checked again, 2nd fault has cleared, so assume rear/downstream Nx Sensor is functioning.
Now to the front/upstream NOX sensor. This is opposite the Adblue injector, followed cable but couldn’t see the connector and ecu. Eventually after much shuffling under the van I managed to get eyes on it, this was followed by the use of many colourful adjectives before the connector eventually came off. Checked codes again, No difference still the single Adblue Dosing Module fault. From this I put my expectation on this NOX sensor not functioning correctly.
Now there was a video of a NOX sensor being removed but not disconnected from a Mercedes GLC, the owner then cleaned the sensing end of the sensor overnight in diesel fuel additive on the basis that this supposedly removes carbon from injectors etc, therefore in concentrated form it should do the same to any present in the NOX sensor. Taking this as a next step before ordering a replacement sensor I attempted to unscrew the sensor. It wasn’t shifting with my large adjustable (this wasn’t slipping either) so I ordered a recommended, from another video, 22mm NOX sensor removal crow’s foot. Due to be delivered in a day or two. Meanwhile I recalled a piece of hand railing was languishing in the shed, eventually finding this 3ft tube I manage to get it onto the adjustable and it loosened the sensor first go. It needs to be said that I had soaked the sensor in penetrating fluid a couple of hours earlier expecting it to be soaking for a couple of days until the crow’s foot arrived.
Soaked overnight in diesel additive, then sprayed with brake cleaner to hopefully remove any loosened debris, it was refitted. Did a fault scan on the reader and this didn’t solve the problem, still the same fault as when I started. Dive a live scan whilst out driving with a co-pilot to monitor readings of course and saw:
Upstream NOX 0%
Downstream NOX varying from 10 % to 190%+ with engine load and speed
Adblue injector once warm might spray anything up to 25%, but only sporadically and not in line with any engine load or speed.
So next step is to wait for replacement dosing module to arrive, install that. If unsuccessful, then it will be a replacement Upstream NOX sensor.
Sorry to be long winded but I wanted to provide as much info as possible.
Hopefully the solution will follow sooner rather than later.
