black_sedan
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You still need the flex fuel sensor installed to get ethanol content
black_sedan
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if we’re talking ecutek you need racerom and the setting for that feature would need to be enabled by your tuner
OP
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Thraxbert
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I don't think you guys are understanding what I'm asking. I'll rephrase.
Running a Zeitronix unit in the vehicle allows the ethanol percentage to reported over CAN. Yes, that allows a tune like BM3 or Ecutek to read the content and adjust the parameters map on the fly AKA "flex fuel."
But that is not what I'm asking, and I'm not talking about tunes. What I'm talking about are PIDs, or On board Diagnostic Parameter IDs. Every car uses PIDs. PIDs are hexadecimal messages sent by the ECU over the CAN bus, and it's why you can hook up an OBD scanner to read a code, see the engine RPM, etc.
Every OBD2 car has a standard set of PIDs. They're all the same. Then each car has vendor-specific or vehicle-specific PIDs that can provide more info. For example, the transmission oil temperature on the Supra does not use the same PID as another car. But if you know the PID, and how to decode it into a human-readable format, you can read and report the info.
That takes me to the Zeitronix. It adds ethanol content reporting to the CAN bus, which means somewhere and somehow it is sending a message that says "this is the ethanol percentage." If this message didn't exist, a tune wouldn't be able to read it from the ECU and wouldn't be able to provide flex fuel support.
So I'm looking to better understand the structure and format of the ethanol message the Zeitronix unit is sending, and how I can read that message with an external device connected to OBD/CAN. This has nothing to do with tuning the car.
Running a Zeitronix unit in the vehicle allows the ethanol percentage to reported over CAN. Yes, that allows a tune like BM3 or Ecutek to read the content and adjust the parameters map on the fly AKA "flex fuel."
But that is not what I'm asking, and I'm not talking about tunes. What I'm talking about are PIDs, or On board Diagnostic Parameter IDs. Every car uses PIDs. PIDs are hexadecimal messages sent by the ECU over the CAN bus, and it's why you can hook up an OBD scanner to read a code, see the engine RPM, etc.
Every OBD2 car has a standard set of PIDs. They're all the same. Then each car has vendor-specific or vehicle-specific PIDs that can provide more info. For example, the transmission oil temperature on the Supra does not use the same PID as another car. But if you know the PID, and how to decode it into a human-readable format, you can read and report the info.
That takes me to the Zeitronix. It adds ethanol content reporting to the CAN bus, which means somewhere and somehow it is sending a message that says "this is the ethanol percentage." If this message didn't exist, a tune wouldn't be able to read it from the ECU and wouldn't be able to provide flex fuel support.
So I'm looking to better understand the structure and format of the ethanol message the Zeitronix unit is sending, and how I can read that message with an external device connected to OBD/CAN. This has nothing to do with tuning the car.
zrk
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Don't loop me into this.
zrk
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You have no idea how much fun that sounds to me.
OP
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Thraxbert
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Okay, maybe I've made progress. Or maybe I've wasted hours of my time today for nothing.
First, we know from Zeitronix itself that it communicates on CAN bus ID 0x00EC hex and 11-bit CAN identifiers.
So I tried the obvious: pinging PID 00EC with Torque. No response.
Okay, so the ECU has different "modes" where different channels of codes are sent. Mode 21,22,23 are often used for vendor-specific things. I tried plugging in 22 EC and got data back! The ECU reported 7E9037F2213. Interestingly, that equates to ~8.0 when you hit this value with the typical (A/255)*100 formula for calculating ethanol percentages on other platforms... Not entirely unreasonable for the e content of 93 gas. Did I get it? Probably not.
As a roundabout verifier, I pinged this interface several times and got the same HEX code back over and over. Ethanol content fluctuates slightly when you're putting it through a sensor, usually some wobble in the first first decimal place, as the car runs. I've seen this in my other car that runs E50. So it's unlikely this 7E9037F2213 response is the ethanol content we're looking for because it came back over and over at the same number.
That takes me back to the 11-bit thing from Zeitronix. A standard CAN message on a car has specific format/encoding that looks like this. This is NOT AN OBD2 MESSAGE.
If we take Zeitronix at face value, then 0x00EC is the default CAN ID of the Zeitronix unless Visconti changes it to something else (which they can, and you can).
Okay, Zeitronix also says:
Data 0 is 8 bits long (meaning bits 0 thru 8 in the data)
Data 1 is 8 bit (-40) to derive Celsius of the fuel (meaning bits 9-16 in the day)
Data 7 is 0x00 for sensor OK, 0x01 for sensor not ok
This gives us some clues about the CAN ID (orange) and CAN data (blue) in the diagram being sent by the Zeitronix unit. That took me here, suggesting I wasn't entirely wrong for suspecting Mode 22.
Mode 22 represents UDS, where you can directly read information by Identfier... identifier... LIKE OUR 0x00EC CAN IDENTIFIER. Case closed here, I need to be in mode 22 but I was using it wrong.
Okay, that's a big clue. We know our CAN ID is 0x00EC (maybe).
We know/think our Service ID (SID) is 22 (this is a hex value).
Standard CAN messages are limited to 64 bits (8 bytes) aka HEX 40.
Byte 1 (8 binary bits) should be the ethanol percentage if we convert to decimal, e.g. 0x38 hex should be 56% ethanol.
Byte 2 is another 8 bits, and if we convert that to decimal and subtract 40 we have the fuel temp in ethanol.
And in the 7th byte, 0x00 = sensor OK or 0x01 = sensor not OK.
And another clue: Zeitronix says that Data 0 (the first 8 bits) contains the eth%
Putting it all together, I'm thinking maybe the "PID" is not a PID at all but a mode 22 UDS query formatted differently.
And we're just guessing it uses the simplest single frame, in which case the query is:
EC (Zeitronix CAN ID 11-bit)
00 (single frame query)
40 (8 bytes data in the message)
22 (service mode)
Data bytes
1. 0-64 (eth)
2. 00-FF(temp)
3. null
4. null
5. null
6. null
7. 00 or 01 (sensor)
OR MAYBE I'M A TOTAL MORON WHO HAS NO IDEA WHAT'S GOING ON AND THIS SHIT WILL NEVER WORK BECAUSE THE FRAMES ARE A PROPRIETARY SIZE AND TORQUE CAN'T RESD THOSE KINDS OF CAN MESSAGES REEEEEEEEE
First, we know from Zeitronix itself that it communicates on CAN bus ID 0x00EC hex and 11-bit CAN identifiers.
So I tried the obvious: pinging PID 00EC with Torque. No response.
Okay, so the ECU has different "modes" where different channels of codes are sent. Mode 21,22,23 are often used for vendor-specific things. I tried plugging in 22 EC and got data back! The ECU reported 7E9037F2213. Interestingly, that equates to ~8.0 when you hit this value with the typical (A/255)*100 formula for calculating ethanol percentages on other platforms... Not entirely unreasonable for the e content of 93 gas. Did I get it? Probably not.
As a roundabout verifier, I pinged this interface several times and got the same HEX code back over and over. Ethanol content fluctuates slightly when you're putting it through a sensor, usually some wobble in the first first decimal place, as the car runs. I've seen this in my other car that runs E50. So it's unlikely this 7E9037F2213 response is the ethanol content we're looking for because it came back over and over at the same number.
That takes me back to the 11-bit thing from Zeitronix. A standard CAN message on a car has specific format/encoding that looks like this. This is NOT AN OBD2 MESSAGE.
If we take Zeitronix at face value, then 0x00EC is the default CAN ID of the Zeitronix unless Visconti changes it to something else (which they can, and you can).
Okay, Zeitronix also says:
Data 0 is 8 bits long (meaning bits 0 thru 8 in the data)
Data 1 is 8 bit (-40) to derive Celsius of the fuel (meaning bits 9-16 in the day)
Data 7 is 0x00 for sensor OK, 0x01 for sensor not ok
This gives us some clues about the CAN ID (orange) and CAN data (blue) in the diagram being sent by the Zeitronix unit. That took me here, suggesting I wasn't entirely wrong for suspecting Mode 22.
Mode 22 represents UDS, where you can directly read information by Identfier... identifier... LIKE OUR 0x00EC CAN IDENTIFIER. Case closed here, I need to be in mode 22 but I was using it wrong.
Okay, that's a big clue. We know our CAN ID is 0x00EC (maybe).
We know/think our Service ID (SID) is 22 (this is a hex value).
Standard CAN messages are limited to 64 bits (8 bytes) aka HEX 40.
Byte 1 (8 binary bits) should be the ethanol percentage if we convert to decimal, e.g. 0x38 hex should be 56% ethanol.
Byte 2 is another 8 bits, and if we convert that to decimal and subtract 40 we have the fuel temp in ethanol.
And in the 7th byte, 0x00 = sensor OK or 0x01 = sensor not OK.
And another clue: Zeitronix says that Data 0 (the first 8 bits) contains the eth%
Putting it all together, I'm thinking maybe the "PID" is not a PID at all but a mode 22 UDS query formatted differently.
And we're just guessing it uses the simplest single frame, in which case the query is:
EC (Zeitronix CAN ID 11-bit)
00 (single frame query)
40 (8 bytes data in the message)
22 (service mode)
Data bytes
1. 0-64 (eth)
2. 00-FF(temp)
3. null
4. null
5. null
6. null
7. 00 or 01 (sensor)
OR MAYBE I'M A TOTAL MORON WHO HAS NO IDEA WHAT'S GOING ON AND THIS SHIT WILL NEVER WORK BECAUSE THE FRAMES ARE A PROPRIETARY SIZE AND TORQUE CAN'T RESD THOSE KINDS OF CAN MESSAGES REEEEEEEEE
Last edited:
Surebob
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sorry for the bump, did you ever make any progress in general on reading different values through OBD port? things like boost, HP, Torque, temps and stuff, i know some custom gauges that are obd based do this and i was wondering if i can figure this out i can make my own 3d printed gauges with those nice smartwatch round OLEDS you can get on ebay.
razorlab
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You are looking for OBD2 addresses? Here you go:
| Channel | OBDII PID | CAN ID Match | Raw Value Mapping | Formula | Units Conversion | |||||||||||||||||||
| PID | Channel Name | Short Name | Units | Precision | Min Value | Max Value | Rate | OBDII PID | Mode | Passive Mode | 29 Bit Mode | CAN ID Match | Mask | Sub ID | CAN Bus | Offset | Length | Source Type | Bit Mode | Endian | Multiply | Divide | Add | Units Conversion |
| 04 | Calculated Load | CalcLoad | % | 1 | 0 | 100 | 10Hz | 4 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 05 | Engine Coolant Temp | ECT | °F | 1 | 0 | 300 | 10Hz | 5 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 06 | Short-Term Fuel Trim - Bank 1 | STFTB1 | % | 2 | -100 | 100 | 10Hz | 6 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 128 | -100 | No Conversion | |||
| 07 | Long-Term Fuel Trim - Bank 1 | LTFTB1 | % | 2 | -100 | 100 | 10Hz | 7 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 128 | -100 | No Conversion | |||
| 0B | Intake Manifold Pressure | MAP | psia | 1 | 0 | 255 | 25Hz | 11 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 14.696 | 101.325 | 0 | No Conversion | |||
| 0C | Engine Speed | RPM | 1/minutes | 0 | 0 | 16383.75 | 25Hz | 12 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 1 | 4 | 0 | No Conversion | |||
| 0D | Vehicle Speed | WheelSpeed | miles/hr | 0 | 0 | 255 | 25Hz | 13 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | 0 | kph --> MPH | |||
| 0E | Timing Advance | Advance | degrees | 2 | -64 | 63.5 | 25Hz | 14 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 2 | -64 | No Conversion | |||
| 0F | Intake Air Temperature | IAT | °F | 1 | 0 | 300 | 25Hz | 15 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 11 | Throttle Position | TPS | % | 1 | 0 | 100 | 25Hz | 17 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 15 | O2 Sensor 2 - Bank 1 (volts) | O2S2B1A | volts | 3 | 0 | 1.275 | 25Hz | 21 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 200 | 0 | No Conversion | |||
| 15 | O2 Sensor 2 - Bank 1 (%) | O2S2B1B | % | 2 | -100 | 100 | 25Hz | 21 | 01h | 2024 | 0 | Disabled | 1 | 4 | 1 | Unsigned | Big | 100 | 128 | -100 | No Conversion | |||
| 1F | Time Since Engine Start | RunTime | seconds | 0 | 0 | 65535 | 1Hz | 31 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 1 | 1 | 0 | No Conversion | |||
| 21 | Mileage With MIL On | MilDistance | miles | 0 | 0 | 65535 | 1Hz | 33 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 1 | 1 | 0 | kph --> MPH | |||
| 2E | Commanded Evap Purge | EvapPurge | % | 1 | 0 | 100 | 1Hz | 46 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 2F | Fuel Level | FuelLevel | % | 1 | 0 | 100 | 1Hz | 47 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 30 | Warmups Since Code Clear | ResetWarmups | 0 | 0 | 255 | 1Hz | 48 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | 0 | No Conversion | ||||
| 31 | Mileage Since Code Clear | ResetDistance | miles | 0 | 0 | 65535 | 1Hz | 49 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 1 | 1 | 0 | kph --> MPH | |||
| 33 | Barometric Pressure | AAP | psia | 1 | 0 | 255 | 1Hz | 51 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 14.696 | 101.325 | 0 | No Conversion | |||
| 3A | O2 Sensor 1 - Bank 1 - Air/Fuel (lambda) | AFR | lambda | 3 | 0 | 2 | 25Hz | 58 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 2 | 65535 | 0 | No Conversion | |||
| 3A | O2 Sensor 1 - Bank 1 - Air/Fuel (mA) | AFRmA | mA | 1 | -128 | 128 | 25Hz | 58 | 01h | 2024 | 0 | Disabled | 1 | 5 | 2 | Unsigned | Big | 1 | 256 | -128 | No Conversion | |||
| 3C | Catalyst Temp - Bank 1 S1 | CatTemp | °F | 0 | 0 | 3000 | 1Hz | 60 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 1 | 10 | -40 | °C --> °F | |||
| 42 | ECU Voltage | ECUVolts | volts | 1 | 0 | 65535 | 1Hz | 66 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 1 | 1000 | 0 | No Conversion | |||
| 43 | Absolute Engine Load | AbsLoad | % | 1 | 0 | 25700 | 25Hz | 67 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 44 | Commanded Air/Fuel Ratio | AFRCommanded | lambda | 3 | 0 | 2 | 25Hz | 68 | 01h | 2024 | 0 | Disabled | 1 | 3 | 2 | Unsigned | Big | 2 | 65535 | 0 | No Conversion | |||
| 45 | Relative Throttle Position | RTP | % | 1 | 0 | 100 | 25Hz | 69 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 46 | Ambient Air Temperature | AAT | °F | 1 | 0 | 300 | 1Hz | 70 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 47 | Absolute Throttle Position B | ATPB | % | 1 | 0 | 100 | 25Hz | 71 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 49 | Accelerator Pedal Position D | APPD | % | 1 | 0 | 100 | 25Hz | 73 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 4A | Accelerator Pedal Position E | APPE | % | 1 | 0 | 100 | 25Hz | 74 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 4C | Throttle Actuator | Throttle | % | 1 | 0 | 100 | 25Hz | 76 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 255 | 0 | No Conversion | |||
| 55 | Short-Term Fuel Trim 2 - Bank 1 | STFT2B1 | % | 1 | -100 | 100 | 25Hz | 85 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 128 | -100 | No Conversion | |||
| 56 | Long-Term Fuel Trim 2 - Bank 1 | LTFT2B1 | % | 1 | -100 | 100 | 25Hz | 86 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 100 | 128 | -100 | No Conversion | |||
| 5C | Engine Oil Temperature | EOT | °F | 1 | 0 | 300 | 10Hz | 92 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 62 | Actual Torque | Torque | % | 1 | -125 | 130 | 25Hz | 98 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -125 | No Conversion | |||
| 67 | Engine Coolant Temp - Sensor 1 | ECTS1 | °F | 1 | 0 | 300 | 25Hz | 103 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 67 | Engine Coolant Temp - Sensor 2 | ECTS2 | °F | 1 | 0 | 300 | 25Hz | 103 | 01h | 2024 | 0 | Disabled | 1 | 4 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 68 | Intake Air Temperature - Sensor 1 | IATS1 | °F | 1 | 0 | 300 | 25Hz | 104 | 01h | 2024 | 0 | Disabled | 1 | 3 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F | |||
| 68 | Intake Air Temperature - Sensor 2 | IATS2 | °F | 1 | 0 | 300 | 25Hz | 104 | 01h | 2024 | 0 | Disabled | 1 | 4 | 1 | Unsigned | Big | 1 | 1 | -40 | °C --> °F |
razorlab
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Easiest place to tap into the CAN bus is the twisted pair in the passenger footwell. Right hand side, under the glove box. Pop off the plastic interior piece and it's right there.
underdonk
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Got it. Thank you. So it seems that @Thraxbert has arrived at the logical conclusion that the software is the limiting factor in this case. There are all sorts of open source CAN sniffing tools available as long as one has the hardware to support them. I have experience with this stuff on the industrial control system side of the shop (toxic and nuclear waste processing), but we use pretty specialized tools (hardware and software) for this purpose. I've seen the open source tools work, though. There are some good, general tools available on the commercial market I've used for this purpose (outside of automotive work) in the past as well. At the risk of stating the obvious, that seems like what's needed here? The answer could be yours for $14,999.Easiest place to tap into the CAN bus is the twisted pair in the passenger footwell. Right hand side, under the glove box. Pop off the plastic interior piece and it's right there.
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