Originally Posted by MBDiesel
Today I got my OBD adapter, loaded Torque and am getting lots of good data.
Has anyone discovered any diesel-specific PID's (or any other for that matter) that could be useful? I'm particularly interested in fuel rail pressure and oil pressure.
Originally Posted by Roadkill
Now, if only someone could get a fuel level, engine hours, or transmission temp PID working...
Originally Posted by ExcursionDiesel
I'm lurking on the RAM 1500 Diesel forum...waiting. Its funny watching them discover some of the same stuff we have.
Ok...so you are using the raw PID scan to see PID 78. Now, how do we add it as a Custom PID? Once that is done it can be exported and shared.
Also, I have the Scanguage2 Xgauge codes for DPF. It reads in between EGT and CAT except during regen where it peaks at 1280°F while EGT is 950°F on flat cruise (during regen).
I have been doing some homework and testing using an WK2 MY14 Diesel Export
I started mainly because I wanted a bit more info on Exhaust temps and DPF load condition. In Australia we've had quite a few problems with the DPF warning immediately
sending the car to limp mode. It appears to be a software problem.
There is a really long thread 900+ posts on the topic in the Export WK2 forum
Is DPF issue for 2014 CRD fixed now?
With an OBD scanner, an app and a bit
a lot of internet searching, I've compiled and tested a list of some of the PIDs that are available in the WK2.
Pretty much everything on the car is run by some kind of control unit. Some of these are acessible via the OBD port. I know that the ECU and the TCU are accessible.
There lots of information to find in there, limited by how long you want to spend reverse engineering (painful) and how confident you are with the maths and the possibility of somehow "bricking" the car's brain.
I'm fairly new to this so at the moment I've concentrated on the parameters that are in the SAE standard. All manufacturers have to implement at least some of these standard parameters. Jeep have given us reasonable amount of info in the "Mode 01" set of PID's. I figured these are pretty safe to play around with since it's all read only.
There is more information on these and the Standard is some thing you can find (or buy)..
Once we start searching for Chrysler / Jeep/ Dodge proprietary codes, this is where it gets a bit murky.
The info on these proprietary PIDs (generally "Mode 22") isn't published and Jeep of course change it around from model to model and even within the same model during the manufacturing cycle.
I read that Chrysler usually have a gateway to lock you out of these. There are ways to get around it by "telling" the ECU that you are a diagnostic tool with a certain PID
which then allow you to see the Mode 21/22 parameters provided you know what you're looking for.
Anyway back to Mode 01. Attached is the relevant piece of the SAE J1979 standard which gives the list and explanation of all the Mode 01 paramters to that standard.
These include many that are for spark ignition engines only and there are some specific to diesel. There are even some specific to the DPF.
I just went searching through this list to see which of these gave data on my WK2 MY14 diesel export mode
There was a bit of maths involved in working out how to display the data to something inteliglble.
This wiki page was helpful up to a point. OBD-II PIDs - Wikipedia, the free encyclopedia
I have laid it out in a spreadsheet for the ones that are supported by my export diesel version. The NA model is different notably with different emissions gear so you might have a few extra readings to play with.
The ones that my export version do not give any data for are grey-ed out.
The NA version has the SCR system so you might? be able to see something in that parameter.
I was mainly interested in the DPF loading condition. Thankfully the MY14 does actually have a parameter to read which we can convert to a percentage loading. we've been using this to see when and how often the regens are occuring.
(The MY13 model in Australia doesn't give the reading unfortunately).
Some handy readings that can be extracted off this standard list are:
EGR valve position
VGT vane position (commanded position)
CAT temp (DPF temp)
EGT - we only have 1 other EGT sensor - does the NA model have 2 ?
Exhaust pressure (not the differential across the DPF)
Engine run time (trip)
Engine run time (total - since last reset)
number of starts (warm ups)
Engine Oil Temp
Charge air temp
Ambient air temp
Intake air temp
Inlet air flow
Fuel rail temp
Fuel rail pressure (commanded value and actual value)
Fuel injection timing
I would be interested to see what differences are in the NA model
eg if any info on the SCR system or a PM sensor.
The transmission Temp seems to be a popular request in a lot of forums everyone from Ram1500, VW tdi, Toyota, etc etc.
It is buried in the proprietary Mode 22 list of parameters in the TCU but the parameters can be read from the OBD port.
There is a thread on a JK forums which has this data for trans temp but it might not be tranferable to WK or WK2.
Our MY14 WK2 has the trans temp on the EVIC so no need to chase that particular one.