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Discussion Starter · #1 ·
ELM327 / ODBII usage on a P38 ?


As many will be aware you can interface an ELM327 type of ODBII ‘scanner’ to the ECU on a P38 and, with the right software on my laptop, you can then – at least in theory – read the DTCs on it. (For those unaware the ELM327 scans the ODBII-type connector on the car and configures the right protocol/speed to enable data communication with the ECU)


On my (’95 P38) it simply shows ‘No DTCs’


(Yes, I know what you are thinking - ‘then just relax and be thankful’, etc)

The point is I have now tried to generate some faults for the ELM327 etc to detect.. but it won’t – apparently - do this.
(So far I have only - briefly - unplugged some temperature sensors).


- The real question is has anyone else had success with this particular PC method ?


- And, is there some fault that I can easily simulate on my P38 that this OBDII ‘scanner’ will pick up to prove it will generate a DTC,

- and does that fault also have to exist for some time before the ECU picks it up ?


(Before you ask yes, the ELM327 method is working fine and definitely talking with the ECU… )

Pretty sure that many others will also have tried this ELM327 approach, too, but we will see !!
 
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Oh well, just me then ?

Not sure if it is the 'ELM327/DTC' bit which has not been tried (by any/many members)....

or the 'how do I simulate faults to pick up with my set-up' bit !?

I will persevere and report back !!
 

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RIP Our Friend
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I imagine not many folks have an Elm unit. In addition most folks don't wanna screw with their rigs to create faults if there are none.
 
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Discussion Starter · #4 ·
Fair comment, RRToadHall: Perhaps then it is worth checking this out for when/if the Check Engine/MIL light (ever) illuminates - for ~30bucks/pop it may well be worth it ? In the meantime as indicated I will investigate further and report back (although I hope it will be a positive report, obviously !)
 

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Ive got an ELM 327 scanner, the blue tooth version. Works fine on my wife's Ford even using a smart phone. I tried it in the early days on my 2000 DSE. No chance - the protocol is not OBDII compliant. Ended up buying a Faultmate.
 
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Discussion Starter · #6 ·
Yes, the ELM327 does not work with diesel beasties, apparently. I can get it to talk with my petrol/GEMS P38 Ok.... and at least can extract various engine data, too; I am just not sure (yet) just how accurate it is.

Probably a better question to have asked would have been 'how do folks who invest in a Faultmate actually know it is working OK' ? There must be a fairly easy way to do this (ie. doing something deliberate to generate a fault). There are loads of 'nasty' ways to do this for sure, pulling off leads to plugs/injectors for instance... but I don't want to soak my cat in unburned fuel and the like !! Any ideas, anyone ?
 

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I've had an Elmscan for several years which I bought to have a look at the LS1 V8 etc in my (then) GM car. I plugged it into the P38 with the Digimoto software and discovered one of the pre-cat O2 sensors was operating incorrectly... so they do work...but having a Faultmate I've not bothered with the Elmscan since...
 
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Discussion Starter · #8 ·
Yes, Hodges - the data/parameters it provides for the O2 sensors is definitely quite useful (and I intend to log it, periodically, just in case !). Do you recall if you also had a Fault Code show up for this, too ?

So far though I have been unable to 'force' a DTC out of the P38, not even a 'Pending' one, and I have concluded that I am not doing things 'drastic' enough to cause this or for long enough - as a fault condition has to exist for some time / several 'drive cycles' before it actually registers (probably) ? Alternatively perhaps by my pulling various sensor leads off [here and there] then the ECU just uses its stored MAP values, instead.... ?

(To Be Continued...)

Really.... has no-one else been curious and/or adventurous enough to try to force a code to 'try out' their BBS stuff and/or Hawkeyes etc - ie. prior to an actual problem emerging ?? [Yes, Ok, I know, 'why wake a sleeping bear' ?!]
 

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Zaccly!:naughty:
 

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1995-2002 Range Rover P38A
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Got the ELM 327 Gizmo today (arrived in a day using Amazon prime). Check some of the Amazon threads and apparently there are two different Chinese ELM 327 based Bluetooth units floating around. The older troubled device has a rubber plug and I was happy to see mine was as described without a rubber plug. Used Torque Pro and it paired and connected without errors; read the codes and managed to reset it. All the default dials worked. Here is a freeze frame output I emailed from the Samsung Galaxy Player:

Freeze frame information:
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Engine Load = 31.373
Engine Coolant Temperature = 81 °C
Fuel Trim Bank 1 Short Term = 0 %
Fuel Trim Bank 1 Long Term = -6.25 %
Fuel Trim Bank 2 Short Term = 0.781 %
Fuel Trim Bank 2 Long Term = -6.25 %
Engine RPM = 706 rpm
Speed (OBD) = 0 km/h


End of report.

The best $25 I spent for a long time.
 
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Discussion Starter · #12 ·
Yes, desertboy, found the same type of data with my [cabled] ELM327 set-up

- Especially useful is the O2 sensor data provided by the S/W as real-time sensor data. To check operation of this I simply disconnected an injector and this showed up immediately in the 'short term trim' [fuel] figures as 0% as with your own diagnosis .... and for ~$30/pop well worth it, for sure !!

I am still experimenting with (not-too- hazardous) ways to 'wake the sleeping bear'...
 

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It was nice to see the Bank 1 O2 Sensor 2 was faulty in real time with this thing. What are you using for the OBD2 protocol? I'm using ISO-9141-2 (seems to detect more PIDs). However, mine is not showing MPG values. It would be nice to program some PIDs for our trucks.
 
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Discussion Starter · #14 ·
Yes, 1SO9141 is the protocol used (auto-detected by the ELM327 of course); Not sure what other S/W will work with your own Android/Bluetooth rig but I have tried several different types with mine: Found 'Touchscan' to be one of the easiest/best, free to trial but costs $20 after 2 weeks..... probably worth it, too !

You are right, the PID set, although useful, is partly limited: I suspect this is a characteristic of the GEMs (engine) ECU.. ? Similarly there also has to be some ('relatively easy') way to use 9141 to talk to other ECUs (HeVac, ABS etc) on the P38 bus.... it's not exactly rocket science, surely.. and regardless of the outrageous [and IMHO unjustified] cost of the T4 stuff.... ?!! (oh-oh, another sleeping bear awoken....)
 

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I need to revisit Story's thread when he cracked the EAS protocol and wrote the software. I have a feeling it uses some of the unused PINs in the connector and may be outside the capabilities of the ELM327. So far, I have only used Torque PRO. Couldn't pair the Bluetooth adapter with a Jail Broken iPod touch to see if GoPoint was any good. Thanks for the tip on other software, I'll give it a try.
 
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Discussion Starter · #16 ·
Yes, the EAS system is a different animal (maybe a polar bear..) but yes it uses different OBD2 pins and also a different protocol to the main ECU bus, and Storey deserves loads of credit for cracking all this as we all know.

There are several other S/W packages around for Android/Bluetooth use, many are more focused on monitoring PIDs with the newer buses - 1850, CAN etc - as you have probably noticed.
 

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I need to revisit Story's thread when he cracked the EAS protocol and wrote the software. I have a feeling it uses some of the unused PINs in the connector and may be outside the capabilities of the ELM327. So far, I have only used Torque PRO. Couldn't pair the Bluetooth adapter with a Jail Broken iPod touch to see if GoPoint was any good. Thanks for the tip on other software, I'll give it a try.
The EAS uses pins 11 and 12 on the OBD connector.No other ecu uses these pins.
 

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Yes, the ELM327 does not work with diesel beasties, apparently. I can get it to talk with my petrol/GEMS P38 Ok.... and at least can extract various engine data, too; I am just not sure (yet) just how accurate it is.

Probably a better question to have asked would have been 'how do folks who invest in a Faultmate actually know it is working OK' ? There must be a fairly easy way to do this (ie. doing something deliberate to generate a fault). There are loads of 'nasty' ways to do this for sure, pulling off leads to plugs/injectors for instance... but I don't want to soak my cat in unburned fuel and the like !! Any ideas, anyone ?
Fully agree with Dave. The diesel p38 does not talk to ELM327 (may be mine was a cheap chinese one) and I guess the BOSCH EDC system is not OBDII complient .
regds
 
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Discussion Starter · #19 ·
If you want to see if your 'cheap clone' is inoperative then just try it on another vehicle, preferably 2001+. The ELM327 (when it is working OK !) is pretty smart, and checks several pairs of pins on the OBD port to see just what protocol (on its list of several) is present, and if/when it finds one it then establishes a link to the ECU...... etc.

I don't know why the diesel ECUs can not be communicated in this manner, it might just be it uses other OBD pins (than the usual ones ?). I do know though that I have seen something similar (somewhere !) that will talk to the TD5 and for ~$50....
 
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