CD7 Gm e67 - No oil pressure via canbus ? | AEM
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Rx7Jordan
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CD7 Gm e67 - No oil pressure via canbus ?

So I have a aem cd7 connected to my canbus e67 Gm/ls3 setup. I can see some sensors were found but there is no oil pressure .. is there something I’m missing ? There is a oil pressure sensor on my ls3 but unsure why I can’t find the PIDs? Any help?

AEM_NS
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You mention PIDs so I presume

You mention PIDs so I presume you're capturing data via OBDII. Unfortunately Oil Pressure isn't a standard PID channel. You can see the full list of Mode 1 PIDs HERE.  

AEM_NS
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There may be a silver lining

There may be a silver lining to this cloud. Our testing has shown that both GM LAN and OBDII run on the same CAN network on GM cars. Right now you're sending OBDII into Port 2. What you'd need to do is tap into the same network and send it over to Port 1 on the dash in order to grab GM LAN.  We've reverse engineered a very large portion of the channels coming over GM LAN on a 2010 Camaro SS and can make a DBC that you can import to grab those channels.  I'll only include the channels that we fully identified and characterized but it'll give you a bunch more data to look at beyond just what's coming through on OBDII.  Give me a couple days to get that DBC put together.  

Rx7Jordan
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When you say tap them into

AEM_NS wrote:

There may be a silver lining to this cloud. Our testing has shown that both GM LAN and OBDII run on the same CAN network on GM cars. Right now you're sending OBDII into Port 2. What you'd need to do is tap into the same network and send it over to Port 1 on the dash in order to grab GM LAN.  We've reverse engineered a very large portion of the channels coming over GM LAN on a 2010 Camaro SS and can make a DBC that you can import to grab those channels.  I'll only include the channels that we fully identified and characterized but it'll give you a bunch more data to look at beyond just what's coming through on OBDII.  Give me a couple days to get that DBC put together.  

 

When you say tap them into port 1 how exactly would I do that? With a analog to canbus adapter? Or is there a easier way using the equipment I already have? I was hoping to be able to read oil pressure over obd2/wiring to can+ and Can-

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

Rx7Jordan
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AEM_NS wrote:

There may be a silver lining to this cloud. Our testing has shown that both GM LAN and OBDII run on the same CAN network on GM cars. Right now you're sending OBDII into Port 2. What you'd need to do is tap into the same network and send it over to Port 1 on the dash in order to grab GM LAN.  We've reverse engineered a very large portion of the channels coming over GM LAN on a 2010 Camaro SS and can make a DBC that you can import to grab those channels.  I'll only include the channels that we fully identified and characterized but it'll give you a bunch more data to look at beyond just what's coming through on OBDII.  Give me a couple days to get that DBC put together.  

So I wired in my analogx today and connected the oil pressure sensor to it, unsure on how to properly set this up? When I insert the analogx dbc it wipes out all of my other sensors since I have to switch from obd2 mode to normal mode. Also unsure on how to set the values to the sensor specs to correctly display a accurate reading. 

So pretty much I need to know is 

-How do I know if this analogx is being seen on canbus to verify it’s working ?

-How do I assign the sensor to display correctly on the dash

-How do I set the specs/values of the sensor to show a accurate reading ?

 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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Sorry but I thought it was

Sorry but I thought it was pretty clear - you need to send the OBDII network to both Port 2 and Port 1. No external analog devices needed. This would mean finding the CAN +/- wires for OBDII and then tapping those and sending it over to Port 1. That's it.

Rx7Jordan
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I currently have Can + and

I currently have Can + and Can - from my e67 ecu going to port 2, so I basically have to run them to port 1 as well? Then it will show my oil pressure from my gm ls3 oil pressure sensor after I load the DBC your going to create?

Could you email the DBC to jordy687@gmail.com ? thanks ! 
 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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Yes, correct.  Need to "split

Yes, correct.  Need to "split" the CAN and send it to both networks on the dash.  Port 2 is running a special application in order to support OBDII but GM LAN is just regular CAN thus it would need to be received by a different network that just running regular CAN and not the special OBDII function.  This should allow you to grab Oil Pressure out of the GM LAN data stream assuming it's there.  As I said before, it's present on a 2010 Camaro SS so presumably it should be on other vehicle applications as well.  Once the DBC is available, we'll most likely post it here on the forum.

Rx7Jordan
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Gotcha I’ll wire that to port

Gotcha I’ll wire that to port 1 today then thank you!

Do you have a time frame when the DBC will be released? 

 

 

 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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Probably by the end of the

Probably by the end of the week.

Rx7Jordan
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Sweet thanks !

Sweet thanks !

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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Slight change of plans.

Slight change of plans. Unfortunately current scheduling won't allow me to create the entire GM LAN DBC right now but I can at least get you oil pressure. One thing to know in advance though is that the scaling I reverse engineered on the Camaro doesn't match a published scaling from GM that I sourced at some point. Are you able to see the live oil pressure value from the stock PCM some how? Because without some point of reference, we won't really know which scaling is correct. FWIW, the difference in scaling values represents an 8 psi difference at max pressure. If you're okay with that then no big deal.

Rx7Jordan
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I don’t have anyway on

I don’t have anyway on viewing it from the pcm unfortunately but my LS3 is out of a 2015 camaro (6.2L LS3) so shouldn’t it match okay? My e67 ecm is from a Gm controller kit but engine is camaro ls3. I can give the dbc a test, I actually do have a older aem oil pressure gauge, if I find the power harness I could try and match the value it shows to the value the cd7 shows and see how they compare. 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

Rx7Jordan
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I found the values on a forum

I found the values on a forum I found on calibrating the sensor. These should be the correct values for my oil pressure sensor: 

“0psi - 0.51v 10psi - 0.76v 20psi - 1.06v 30psi - 1.36v 40psi - 1.67v 50psi - 1.96v 60psi - 2.27v 70psi - 2.58v 80psi - 2.89v 90psi - 3.22v 100psi - 3.60v  If you plot it, it extrapolates nicely to 4.5v at 130psi. i.e. 

110psi - 3.9v

120psi - 4.2v

130psi - 4.5v”

 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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That's the analog calibration

That's the analog calibration.  That'd be the calibration the ECU would use to convert volts to pressure.  The Oil Pressure output over GM LAN is already scaled in pressure units and an appropriate scalar is needed to go from a raw bit value to pressure.  I've gone ahead and made a quicky single channel DBC using the documented scaling value - right click the link below and save as.  Its base units is in kPa gauged so you'll have to make a conversion channel to get it to read in PSI gauged.

Please keep in mind that I don't have a GM LAN vehicle to validate this on right now but I believe it's setup correctly.  If it's incorrect, I can update it.  Last thing - GM LAN runs at 500kbit/sec.

Rx7Jordan
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I’ll wire it to port 1 and

I’ll wire it to port 1 and give this dbc a try in a little here. I did notice there was oilpress and oilpress_raw. What’s the difference ?

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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Raw is the raw bit value

Raw is the raw bit value input and not raw is the scaled channel value with units.

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So I created two values on my

So I created two values on my display.. my created output converted from kpa to psi shows 42psi while the raw output with no conversion shows 388kpa which is about 56 psi 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

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So it does work thanks !! So

So it does work thanks !! So I just would use that output called oilpress and not oilpress_raw? 

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I’m not exactly sure if it’s

I’m not exactly sure if it’s accurate because it’s a newer ls3 with 13k miles. Oil pressure is about 34psi cold. That 388kpa @ 56psi seemed more right. I’ll have to find my harness for my old aem oil pressure gauge and compare them.

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

AEM_NS
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I think you're saying that

I think you're saying that your converted channel doesn't match up with the base channel that's in kPag.  Don't call it the "raw" channel - it's not raw.  Raw is the input that's received over CAN that outputs in a decimal bit value.  If you mean the channel that the DBC created, call it the base channel, not raw.  We have to be tight with our naming otherwise things can get mixed up easily.

It sounds like your converted OilPress PSIg value is roughly 14psi lower than it should be.  I'd wager a guess that you used an incorrect conversion scalar.  See below that kPa to PSIg has an offset of -14.7 when the conversion from kPag to PSIg does not.

When you do a conversion channel, you always reference the scaled base channel that has units and NOT the raw channel.  Applying a conversion channel to a raw bits value will get you a very wrong channel reading.

I'm glad to hear this worked.  It'll be cool once I can validate and release the whole GM LAN DBC.  yes

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Any way I can give you a

Any way I can give you a quick call just to verify i am doing it correctly.

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

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On the Scalars tab the

On the Scalars tab the OilPress_Scalar from dbc says scalar: 4 and offset: 0.

Btw do I leave termination resistor enabled ?

 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

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The OilPress is the base and

The OilPress is the base and oilpressure is the converted one I made.

 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

drewz
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Did you ever get GMlan dbc done? I need also.

Thanks

highlander
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same boat too...  

same boat too...
 

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Send me an email jordy687

Send me an email jordy687@gmail.com 
I can send you my layout with the added DBC file for oil pressure.

drewz wrote:

 

Did you ever get GMlan dbc done? I need also.

Thanks

highlander wrote:

same boat too...
 

IG: Rx7Jordan | LS3/T56/8.8 swapped 1994 Mazda Rx7 FD3S | AEM CD-7 | AEM CD5/CD7 help/design share group: https://www.facebook.com/groups/233959727209825/?ref=br_rs

highlander
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Well... the problem with this

Well... the problem with this setup is 1) it sort of utilizes both ports and you cannot add anything else to them. 2) with the current setup it interferes with diagnostics from scan tools or other obd tools.

You should allow the ability to add additional dbc configs to the same list as an import in order to not use both channels.

How do you add mode 22 pids into port2? i figured out how to add broadcast data, but cannot figure out how to do the actual requests like you do in your dbc.

If you could clarify all this it would be great. Thanks

AEM_NS
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highlander wrote: Well... the

highlander wrote:
Well... the problem with this setup is 1) it sort of utilizes both ports and you cannot add anything else to them.

You can add more to Port 1 - just so long as it's at the same net baud.

Quote:
2) with the current setup it interferes with diagnostics from scan tools or other obd tools.

So unplug the dash and then use your other diag tools. 

Quote:
You should allow the ability to add additional dbc configs to the same list as an import in order to not use both channels.

You can already do that but you're limited to Port 1 because Port 2 is running a special CAN OBDII function.  Sorry but that's just how it works.  There are two CAN ports and one is being used for a special function so that leaves you with one other net.  If you want to send it Oil Pressure from GMLAN then anything else that gets added needs to run at 500k.   

Quote:
How do you add mode 22 pids into port2? i figured out how to add broadcast data, but cannot figure out how to do the actual requests like you do in your dbc.

Mode 22 PID access isn't a supported functionality in the dash.  

highlander
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When driving with a customer

When driving with a customer and scanning it is good that hte driver has its dash. When we are datalogging in a race, it is good that driver has its dash. Hence why broadcast data works best...If mode 22 is not supported how are you requesting the data like STFT and a few others not available via broadcast?
Nothing I am saying is to knock down your product. It is really nice and we like it, its just to make it suit our needs a little better.
For instance, if you could have one screen be able to start the PID requests when its on display and release the bus when you quit the screen and use broadcast data alreday setup for the other screen it might actually be perfect.

AEM_NS
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Short Term Fuel Trim is

Short Term Fuel Trim is already a standard OBDII PID. As you can see looking through the software, there is no means for requesting Mode 22 PIDs. I appreciate that you're not knocking the product but to be clear, none of our sales or marketing materials claims that the CD dash can do Mode 22 PIDs or special PID requests so I don't think we ever let on to the idea that it's a standard function. Not saying it isn't something that might exist in the future but it doesn't exist now.

Do you actually have a problem with your setup?  You have Port 2 committed to OBDII at 500k and piggy back the same net over to Port 1 for GMLAN channels.  You can add in anything else you want to Port 1 so long as it's running at 500k.  Besides not being able to get Mode 22 PIDs, I'm not sure I'm understanding what problem you actually have.  

And BTW, the channel requests are already driven by which channels are being displayed on a page.  This is done to conserve speed/bandwidth.  But that doesn't mean the CAN chip can drop one net and pickup a different one at a different speed or something.  That just not how things work.