Denso ES27C AC Compressor control (Toyota/Lexus)

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Denso ES27C AC Compressor control (Toyota/Lexus)

Post by xp677 »

A quick detour from my current Lexus projects, a Denso ES27C arrived in the mail today, I set about building a controller for it.

I had already pulled data from a GS450h, it looks like this:

Code: Select all

	
		Byte 1	Byte 2	Byte 3	Byte 4	Byte 5	Byte 6	Byte 7	Byte 8	Byte 9	Byte 10
Packet 1	0	0	0	0	0	0	26	103	0	125
Packet 2	0	0	0	4	0	0	154	108	0	245
Packet 3	0	0	0	4	0	0	29	108	0	113
Packet 4	0	0	0	4	0	0	29	109	0	113
Packet 5	0	0	1	4	0	0	154	110	0	242
Packet 6	0	0	1	4	0	0	30	110	0	110
Packet 7	0	0	1	4	0	0	154	110	0	242
Packet 8	0	0	1	4	0	0	30	108	0	112
Packet 9	0	0	1	4	0	0	154	109	0	243
Packet 10	0	0	1	4	0	0	30	110	0	110
Packet 11	0	0	1	4	0	0	154	108	0	244
Packet 12	0	0	1	4	0	0	30	109	0	111
Packet 13	0	0	1	4	0	0	154	110	0	242

These were the first packets pulled from the car when it was started. There seems to be an initialization and then repeated packets.

Byte 9 is a checksum. It's the LSB of the sum of bytes 3 thru 7, subtracted from 254.

The data is sent as a clocked serial signal, looks very much like SPI, but is far too slow to function with SPI transceivers.

Image

Each clock cycle is 3.2ms, each byte of data takes 26ms to receive, and each packet of 10 bytes is received over 315ms, with a 80ms gap in between. So less than 3 packets per second.

I wrote a basic program to bit-bang this out of an Arduino Nano. One interesting point is that the logic level is 12V, so I added some transistors and an optoisolator to communicate with this unit. This code produces exactly the same output as the HV ECU in the car.

Code: Select all

#define LEN 10 //message length
#define PACKET_GAP 76000 //79100 microseconds between packets
#define BYTE_GAP 6463 // 9650 microseconds between bytes
#define ETI_DROP 22500 //drop eti to 0v this long after packet transmission
#define CLK_HIGH_TIME 1573 //actually 1550 high clock pulse duration
#define CLK_LOW_TIME 3247 //actually 1700  low clock pulse duration (they are different for some reason)

byte response[10]={0,0,0,0,0,0,0,0,0,0};
byte data1[10]={0,0,0,0,0,0,26,151,0,125}; //packet 1
byte data2[10]={0,0,0,4,0,0,154,108,0,245}; //packet 2-4
byte data3[10]={0,0,1,4,0,0,154,110,0,242}; //packets after
byte data4[10]={0,1,2,3,4,5,6,7,8,9};  //testing

unsigned long lastpacket=0,lastbyte=0,clk_hightime=0,clk_lowtime=0;

bool bytecomplete=0;

#define ITE 12 //arduino pin. can be any pin, doesnt have to be SPI pins
#define ETI 11 //arduino pin. can be any pin, doesnt have to be SPI pins
#define CLK 13 //arduino pin. can be any pin, doesnt have to be SPI pins

void setup()
{
pinMode(ITE, INPUT);
pinMode(CLK, OUTPUT);
pinMode(ETI, OUTPUT);

Serial.begin(115200);
}

void transferbyte(byte packet_id,byte dataindex)
{
  if(micros()-lastbyte>BYTE_GAP)
  {
    for(int i=0;i<8;i++)
    {
      clk_hightime=micros();
      clk_lowtime=micros();  

      //send ETI primitive packet handling for proof of concept, easily improved in future
      switch (packet_id)
      {
        case 1: digitalWrite(ETI, bitRead(data1[dataindex],i));break;
        case 2: digitalWrite(ETI, bitRead(data3[dataindex],i));break;
        case 3: digitalWrite(ETI, bitRead(data3[dataindex],i));break;
        case 4: digitalWrite(ETI, bitRead(data4[dataindex],i));break;
        default: digitalWrite(ETI, bitRead(data4[dataindex],i));
      }
      while(micros()-clk_hightime<CLK_HIGH_TIME)digitalWrite(CLK,0);
      
      bitWrite(response[dataindex], i, digitalRead(ITE)); // capture ITE
      
      while(micros()-clk_lowtime<CLK_LOW_TIME)digitalWrite(CLK,1);
    }
    //digitalWrite(ETI,0); //in case last bit of byte was 1 (inverted logic)
    
    lastbyte=micros();
    bytecomplete=1;
  }
}

void transferpacket(byte packet_id)
{
  if(micros()-lastpacket>PACKET_GAP)
  {
    for(int i=0; i<LEN; i++)
    {
      while(!bytecomplete)transferbyte(packet_id,i);
      bytecomplete=0;
    }
    lastpacket=micros();
  }
  
  //HVECU in car holds ETI in last state for this long before sending 0
  if(micros()-lastpacket>ETI_DROP)digitalWrite(ETI,1);
  }

void serialdiag(byte packet_id)
{
    Serial.print("Sent: ");
    switch(packet_id)
    {
      case 1: {for(int i=0;i<LEN;i++){Serial.print(data1[i]);Serial.print(" ");};break;}
      case 2: {for(int i=0;i<LEN;i++){Serial.print(data2[i]);Serial.print(" ");};break;}
      case 3: {for(int i=0;i<LEN;i++){Serial.print(data3[i]);Serial.print(" ");};break;}
      default: {for(int i=0;i<LEN;i++){Serial.print(data4[i]);Serial.print(" ");};}
    }
    Serial. print("\n");

    Serial.print("Received: ");
    for(int i=0;i<LEN;i++){Serial.print(response[i]);Serial.print(" ");}
    Serial.print("\n");
    Serial.print("\n");
}
    
void loop()
{
  transferpacket(2);
  serialdiag(2); 
} 
Note that due to the nature of this code causing the processor to wait until certain timings events are reached, this microcontroller would likely need to be dedicated to the role of communicating with the compressor. I have added inputs on my schematic for an AC button, pressure switch (trinary switch) and evaporator thermo switch, these would be to start and stop the data transmission. Trying to run other EV things from this unit may cause unexpected results, and would likely affect the timing of the data transmission to the AC compressor.

My plan for the 3 switch inputs is to just put an "if(all switches closed){run the compressor}" in the main loop. The serialdiag() functino will be replaced by a CAN transmit function, if the AC compressor is found to produce any useful data.

I've attached a schematic of the circuit I used. Note the pain numbers have changed - I've freed up the SPI pins so I can add a CAN controller in the future. I'll get this board fabricated when I next place an order.

I'm currently facing two issues:

1. The AC compressor pinout. I believe it is:

1 - CLK
2 - ETI (data from HV ECU to compressor)
3 - ITE (feedback from compressor to HV ECU)
4 - STBI
5 - GND
6 - 12V

However, the service manual contradicts itself over which pin is ITE and which is ETI. From metering the two, pin 2 has the same specs as CLK, while pin 3 is pulled up when pin 6 is connected to 12v via a 1M resistor. I am going with the assumption that my list above is correct.

To activate this unit, the STBI line needs to be connected to ground. Doing so causes the unit to pull 14mA from the 12v line. This isn't enough to power the unit, I believe that the unit is disabled until it sees voltage on the HV DC connector. I opened the unit, there is a sensing circuit connected to these lines. Likely the inverter is shutdown until it receives adequate HV voltage. I tried 12v. Nothing happened.

So, I'm about 10 hours in and have made plenty of progress already. I'll likely put this project on hold until I have access to a 288V DC source to try this again. I've posted this now in case anyone else wants to use my work so far to attempt to control a compressor of their own. These are widely available AC compressors, and if they can be controlled, it would provide a cheap source of AC for electric car conversions.
Attachments
es27c_control.pdf
(75.99 KiB) Downloaded 635 times
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by arber333 »

Good job!

I have Leaf gen 1 compressor that uses some strange serial bus connection. I think it works off 5V high and 1.5V low which creates problems how to detect signal low with serial adapters. You have any experience with that maybe?

tnx

Arber
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

If the communication is slow enough, you can just drive digital pins directly, and read the output through your code.

5v high and 1.5v low sounds like a differential signal. Is this measuring the data pin to ground? Or is it a pair for TX and a pair for Rx?

You could drive a PWM pin to whatever duty cycle would create 1.5v from a RC circuit. The issue is that the RC circuit would be slow to change state, so this would only work if the communication rate is slow enough.

As for reading it, you could use an analog pin.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

When the compressor is running, the ETI signal look like this:

Code: Select all

148	18	0	4	29	82	46	96	0	88
147	18	0	4	29	82	166	96	0	225
138	18	0	4	29	82	46	96	0	98
125	18	0	4	29	82	166	96	0	247
167	18	0	4	29	83	166	96	0	204
And the response from the compressor looks like this:

Code: Select all

Compressor stopping									
208	15	128	0	160	208	15	128	255	160
208	15	128	0	160	208	15	128	255	160
208	15	128	0	160	208	15	128	255	160
208	15	128	0	160	208	15	128	255	160
208	15	128	0	160	208	15	128	255	160
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
									
Compressor Starting									
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
0	0	0	0	255	0	0	0	0	255
80	20	128	0	27	80	20	128	0	27
80	20	128	0	27	80	20	128	0	27
80	20	128	0	27	80	20	128	0	27
futher along									
33	20	128	0	74	33	20	128	0	74
33	20	128	0	74	33	20	128	0	74
futher along									
242	19	128	0	122	242	19	128	0	122
242	19	128	0	122	242	19	128	0	122
much further along									
10	19	128	0	98	245	19	128	0	98
Checksum is the same, it's byte 10. It's 255 minus the LSB of the sum of the other 9 bits.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by johnspark »

schematic
schematic
Here is the schematic for a Toyota Camry Hybrid AVV50L/R.

it has
DIN instead of ETI
and
DOUT instead of ITE

So pins are:
1 - CLK
2 - DIN (data from HV ECU to compressor)
3 - DOUT (feedback from compressor to HV ECU)
4 - STBI
5 - GND
6 - 12V (IG1), via 7.5A fuse.

Toyota Camry Hybrid AHV40 is identical, except pin 6 is fed by 12V via 10A fuse.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

The Lexus compressor has the pins labelled as DIN and DOUT on the PCB inside (I don't recommend removing the cover, it's rather sticky in there), the ETI and ITE are from the service manual. DIN and DOUT are referenced in other parts of the service manual as well. So it looks like Toyota couldn't decide what to call them!

The service manual does contradict itself on which is data to and from the compressor. I think it's established now that pin 2 is data into the compressor.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by johnspark »

forgot to add the picture XP, kind regards.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

That picture is very useful. I don't have a copy of it in my GS450h service manual so many thanks for sharing.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by Zapatero »

Any news on this topic?
I'd like to use the Leaf AC Compressor for my Toyota GT86 build, but i don't know how!
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

No new news, I will look into this again when I am further along in my project. The initial work was just so I could get rid of the GS450h that I purchased for this data.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by Erika »

Hi,
I want to doing some easy test with Denso ES27C compressor, but I have some problems. I can't find the matching connector for this compressor(both the control signal connector and the high voltage connector ). I saw that you have down some test to ensure the correct control pinout. How could you connect those signal to the compressor? Do you know how could I find the matching connectors?
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by johnspark »

Erika, I have a Toyota Hybrid Camry AVV50R on my front lawn it has a Denso compressor in it. Hopefully same as yours. Will connect my Picoscope to the signals of the compressor for you. Been meaning to do this for ages, but other things keep popping up...
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

The signal connector is a Sumitomo TS-series 6189-1083.

The power connector I don't know, mine came with the connector and cable.

The pinout is written on the PCB under the cover. Sorry, I don't have it written down. There is a clock, data in, data out, and "STBI", which is either an enable, chip-select, or data request line.

Edit: I found this in one of my old documents, not sure what car it's for, I think one of the generations of Prius:

1: "CLK" green to DA1:19 to PMC:19 "CLK"
2: "DIN" yellow to DA1:20 to PMC:31 "ETI"
3: "DOUT" red to DA1:21 to PMC:30 "ITE"
4: "STBI" white to DA1:22 to PMC:20 "STB"
5: "GND" white-black to DA1:17 to ground point A4
6: "IG1" violet to DA1:18 to share a 10A fuse in (IG)

Definitely not for GS450h as they use white/yellow/black/green for the 4 "data" wires.


Edit: and johnspark posted the same on page 1 of this thread. So there you go.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by arber333 »

xp677 wrote: Thu Apr 16, 2020 7:34 pm The signal connector is a Sumitomo TS-series 6189-1083.

The power connector I don't know, mine came with the connector and cable.

The pinout is written on the PCB under the cover. Sorry, I don't have it written down. There is a clock, data in, data out, and "STBI", which is either an enable, chip-select, or data request line.
How did you undo the cover? I see some strange pattern bolts holding the cover shut on Leaf AC compressor inverter. I dont have the tool to take them off.... Any idea?
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

I don't remember it being a challenge, mine must have had regular phillips or torx bolts. Either that or I just gripped them with pliers? Sorry, I forget.

There is a sealant around the cover as well but a craft knife can sort that out.

Edit: I just did a quick google search and the first one I saw had phillips screws. I guess mine did too. https://www.aliexpress.com/i/32851143490.html

Looking at the pictures, the Leaf seems to have the same pump/motor as the Lexus RX and GS, but a different inverter housing.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by arber333 »

Well this is the inverter cover. Bolts are strange and i cant even grip them with pliers since their heads are rounded.
Leaf compressor has inverter from the side not on top.
Attachments
IMG_20200420_115750.jpg
IMG_20200420_115759.jpg
IMG_20200420_115807.jpg
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by xp677 »

You should be able to remove those with a hammer and chisel to push them round.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by arber333 »

xp677 wrote: Mon Apr 20, 2020 8:55 pm You should be able to remove those with a hammer and chisel to push them round.
Yes, i did. But now i see the IGBT chip is soldered and bolted in from below. There is no way to get the PCB off.
Also i just got the Prius compressor. It is a little smaller unit, but it only has 3phase cable. And i got it to work so i wont be messing with Leaf compressor anymore.
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Re: Denso ES27C AC Compressor control (Toyota/Lexus)

Post by xp677 »

Thanks. Since we don't know if the communication protocol is the same for the Leaf units, I'll change the thread title to only cover Toyota/Lexus.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by Erika »

johnspark wrote: Thu Apr 16, 2020 10:21 am Erika, I have a Toyota Hybrid Camry AVV50R on my front lawn it has a Denso compressor in it. Hopefully same as yours. Will connect my Picoscope to the signals of the compressor for you. Been meaning to do this for ages, but other things keep popping up...
Hi, how about your job with the compressor? I try to find the correct connector and I think I found them. But when I give the high power voltage (tried 180V~285V) and the control signal voltage (12V, 1A), the compressor didn't work and I cannot see any useful signal from the clk or the ITE :( . If you have any good news on the testing, please tell me.
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Re: Denso ES27C AC Compressor control (Lexus, Leaf, etc)

Post by Erika »

xp677 wrote: Thu Apr 16, 2020 7:34 pm The signal connector is a Sumitomo TS-series 6189-1083.

The power connector I don't know, mine came with the connector and cable.

The pinout is written on the PCB under the cover. Sorry, I don't have it written down. There is a clock, data in, data out, and "STBI", which is either an enable, chip-select, or data request line.

Edit: I found this in one of my old documents, not sure what car it's for, I think one of the generations of Prius:

1: "CLK" green to DA1:19 to PMC:19 "CLK"
2: "DIN" yellow to DA1:20 to PMC:31 "ETI"
3: "DOUT" red to DA1:21 to PMC:30 "ITE"
4: "STBI" white to DA1:22 to PMC:20 "STB"
5: "GND" white-black to DA1:17 to ground point A4
6: "IG1" violet to DA1:18 to share a 10A fuse in (IG)

Definitely not for GS450h as they use white/yellow/black/green for the 4 "data" wires.


Edit: and johnspark posted the same on page 1 of this thread. So there you go.
Hello, thank you for your information and I find the correct connector finally. So I did some easy test on my compressor, but there are still some problems.
I give a control signal voltage between the pin IG1 and pin GND (12V, 1A),and a high voltage between pin PGND and PBAT (I changed the voltage from 180V, 30mA to 285V, 30mA). Consider about the safety, I don't want the compressor run when I test it, so I make the STB pin keep a high level volatge during the test. I want to see some signal form the clk or the ITE, but when I connect the signals to the scope, I cannot see and useful signals. The pin2 and pin1 keep a low voltage (about 70mV) and the pin3 keep a high voltage (about 11.5V).
Do you know more about the communication protocol of the compressor? A document says that the communication protocol is the PWM communication and it means I only need to give a PWM to the ETI and when I change the duty cycle the rotate speed will be changed. And the pin CLK is used to check the fault signals by give different pluse number. For my test, I give the correct signal voltage and the right high voltage, but the STB is high level, the fault signals should have 6 pulses. So as my expect, I will see 6 pulses when I connect the CLK to the scope. But as I said, I saw nothing :cry: :cry: . I think maybe the document is not for the ES27C.
Do you have any ideas about the test? If you have some suggestions, I can do other tests to learn more about the compressor.
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Re: Denso ES27C AC Compressor control (Toyota/Lexus)

Post by xp677 »

I've attached some files from my testing, these were made using Sigrok PulseView, so you can open them in there and see what the communication looks like.

testing.zip
(4.27 MiB) Downloaded 187 times

I think the CLK needs to come from your controller. Maybe try sending a clock pulse to the CLK pin and see what comes from ITE?

From the service manual, these are not PWM, they are serial communication.
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Re: Denso ES27C AC Compressor control (Toyota/Lexus)

Post by Erika »

xp677 wrote: Wed Apr 29, 2020 3:05 pm I've attached some files from my testing, these were made using Sigrok PulseView, so you can open them in there and see what the communication looks like.

testing.zip


I think the CLK needs to come from your controller. Maybe try sending a clock pulse to the CLK pin and see what comes from ITE?

From the service manual, these are not PWM, they are serial communication.
Hi, I saw your testing documents. But there are too many files, I cannot understand them well. Could you provide some explainations if it is convenient ? And as you said that from the service manual, the communication mode is serial communication. I think if we want to make the compressor run, we should know more information about the serial communication such as the data format (the address and something else). Do you find any more information about the data format in the service manual ? I will be very appreciated if you could send the service manual to me.
By the way, do you know the difference between the ES27 and ES27C.
And another question is, how could you let the compressor run without high voltage (i saw some testing files named "running steady, no ground on second half").
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Re: Denso ES27C AC Compressor control (Toyota/Lexus)

Post by xp677 »

Erika wrote: Wed May 06, 2020 6:20 am Hi, I saw your testing documents. But there are too many files, I cannot understand them well. Could you provide some explainations if it is convenient ?
I don't really understand many of them either. The filename is the description of what was happening, and the traces in the documents indicate the CLK, ITE, or ETI signals. Some of the documents do not have all 3, because there was an issue with the signals grounding through my logic analyzer.
Erika wrote: Wed May 06, 2020 6:20 am And as you said that from the service manual, the communication mode is serial communication. I think if we want to make the compressor run, we should know more information about the serial communication such as the data format (the address and something else). Do you find any more information about the data format in the service manual ? I will be very appreciated if you could send the service manual to me.
Visit lexustech.eu, you can pay EUR6 for 1 hours access to the manual. I only have a few pages which I saved. See here for everyting I have:
Service Manuals.zip
(4.01 MiB) Downloaded 240 times
The file "ac compressor.html" should be useful. You will need to extract all the files for the images to load.

In the document, it mentions the trouble code "P3108 Serial communication malfunction".

That, and the fact that it has TX,RX and CLK, tells me that it is a synchronous serial communication.

You can look at some of the waveforms to see the data format.
Erika wrote: Wed May 06, 2020 6:20 am By the way, do you know the difference between the ES27 and ES27C.
No, sorry.
Erika wrote: Wed May 06, 2020 6:20 am And another question is, how could you let the compressor run without high voltage (i saw some testing files named "running steady, no ground on second half").
I did not disconnect the high voltage, the "no ground" probably meant the ground for my logic analyzer to the chassis. I was having issues with ground interference during the testing.

Look at the file "compressor data.xlsx", that seems to have some of the information decoded.
lucencyfang
Posts: 1
Joined: Mon May 11, 2020 6:35 am

Re: Denso ES27C AC Compressor control (Toyota/Lexus)

Post by lucencyfang »

Have any progress recently?I have the schematic and just begin this project。
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