OBD plug devices

[Sundowner2]

We have just completed a 7000 km trip towing a caravan through outback Queensland....The Navara performed perfectly the entire distance.
Before leaving I purchased a OBD device to plug into the port under the dash...info such as engine temp in degrees, alternator voltage could be seen, plus some other info such as boost pressure, ambient and intake temperatures.
The device I brought was at the lower end of the price range...a lot of information was not displayed, there are many fields that remain blank .....AT temperature for example, I am guessing that if I had of brought a better device I may have been able to see much more.....has anyone fitted one of these devices and what have they been able to view?....
2012 D40 2.5L diesel.
Cheers,
Paul

 

[bods]

Hey mate.

You will find all those devices report only what the ecu can "see." In other words, if there is a sensor on that particular component that the ecu gets data from, you will be able to look at it through that device.

Not all components will have sensors on them. Some may also be fitted with a simple "on-off" switch, so once they get to a certain resistance or voltage value they simply turn on or off. A good example is the oil pressure switch, once there is pressure above the minimum range, the light on the dash goes off, however you can't use it to measure actual oil pressure.

I hope this helps.

Sent from my moto g(6) plus using Tapatalk

 

[Sundowner2]

Thanks bods...I thought that might be the case....AT, DPF temps probably the same.

Regards,
Paul.

 

[bods]

Yeah, a lot of it will have "switches" that activate above a certain temperature and tell the ecu it is too hot, etc, but can't be used to measure an actual value.

The only option is to fit your own aftermarket gauges to measure it accurately.

Sent from my SM-T813 using Tapatalk

 

[Old.Tony]

If you're using a generic ELM327 bluetooth adapter, you'll find that it's quite capable of querying the ECU for the stock OBD-II compliant data.

I don't think Nissan went the whole hog with the ECU getting ALL of the data. AT temperature is available, but only to the TCM. DPF temps before and after are measured, I'm not sure why we can't get that data but I'm willing to bet the ECU does some non-standard stuff with it and only provides the difference as a yardstick. DPF pressures before and after are done by comparative difference only, and that's provided by a single sensor mounted on the side of the engine bay near the ABS. You'll find two metal tubes running up to two rubber hoses which go up to a single black sensor and this provides an "offset" data to the ECU, which indicates that one side of the DPF or the other has a higher pressure.

Custom gauges are the only answer, we can't add data to the ECU and I don't know if it's even possible to put a more informative ECU in the car that can still operate a 4 cyl diesel, you'd have to change it to a 12-cyl boxer engine with a dancing horse on it to get that sort of data.

 

[Sundowner2]

Thanks for you response Tony....I am a firm believer in the old adage that temperature tells all....an increase in coolant temp beyond normal obviously indicates a possibly issue developing...I therefore like to see the coolant temp expressed digitally rather than by a needle....that's why I also like to be able to see transmission and DFP temps etc.

 

[KevinE]

If you're using a generic ELM327 bluetooth adapter, you'll find that it's quite capable of querying the ECU for the stock OBD-II compliant data.

I don't think Nissan went the whole hog with the ECU getting ALL of the data. AT temperature is available, but only to the TCM. DPF temps before and after are measured, I'm not sure why we can't get that data but I'm willing to bet the ECU does some non-standard stuff with it and only provides the difference as a yardstick. DPF pressures before and after are done by comparative difference only, and that's provided by a single sensor mounted on the side of the engine bay near the ABS. You'll find two metal tubes running up to two rubber hoses which go up to a single black sensor and this provides an "offset" data to the ECU, which indicates that one side of the DPF or the other has a higher pressure.

Custom gauges are the only answer, we can't add data to the ECU and I don't know if it's even possible to put a more informative ECU in the car that can still operate a 4 cyl diesel, you'd have to change it to a 12-cyl boxer engine with a dancing horse on it to get that sort of data.

Hi Tony, It's all there in a Mitsubishi 4 cyl diesel all the way back to the year 2,000 at least, I can't see why Nissan can't do it?

Personally, I like the Nissan way of doing it. The less electronics the better IMO.

 

[Sundowner2]

Its been awhile since I first posted this item....just wondering if anything has developed in that time?....perhaps some software updates or a new smarter OBD device?....thanks.