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Torque » Torque OBD ECU Scanner » Torque Discussion / Ideas » Idle Air Control

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Author	Topic: Idle Air Control

Gambalunga

Member
Posts: 11

MAP sensor and Idle Air Control
on: October 30, 2013 (GMT)

I have a Morgan Plus 4 2012 build that uses a Ford Duratec 2.0L petrol engine similar to that used in the Ford Focus in some markets. This engine uses a MAP sensor and an idle air Control valve. I am not certain but I believe that the ECU automatically controls the idle by adjusting the ignition advance, the idle air control valve, and obviously fuel to adjust for changes in intake air. In this way the idle speed remains reasonably constant when the airconditioner is turned on. Yes, I know you are wondering why you would want aircon on a sports car, but if you lived where I live you would want it in summer too.

I would like to have some idea of what the MAP sensor and the idle air Control valve are doing but I can not find any sensor which gives me this information.

I can’t find anything in the list of Ford PIDs so I can only assume that I need to add a couple of PIDs, but I have no idea what, or how to do this.

I am using Torque Pro.

Thanks

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: October 30, 2013 (GMT)

On some older Fords it was pid 221153.

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: October 30, 2013 (GMT)

Thanks. I think that may be correct. I found a list of Ford PIDs at http://diagrams.hissind.com/?p=458. IAC is listed as 1153.

Now all I need to do is work out how to read it in Torque and perhaps create a digital instrument.

I have just realised that MAP is already available as it is “Intake Manifold Pressure”

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: October 30, 2013 (GMT)

Goto SETTINGS>MANAGE EXTRA PIDS/SENSORS
then add custom pid

Header: Auto or Blank
Mode/Pid: 221153
Equation: A or ((A*256)+B)
Units: %

Test the pid while in the pid editor to see the raw
hex data to see if one or two data bytes are returned.

Typical % equation (A*(100/255))

Once the pid is created it will appear in the menu
when adding display in the dashboard. Names must
be unique.

Add the display in the dashboard by pressing menu
or by long pressing in an empty space in the dashboard.

Long pressing the display after it has been created will
bring up menu options for the display. Menu can be
swiped up and down.

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: October 31, 2013 (GMT)

Thanks.

I tried that but no raw data. Either the PID is incorrect for the ECU fitted (always possible) or the data is not accessable. I always thought that the Morgan was fitted with a Ford ECU but it may be either something else or customised specifically for Morgan.

Is there any way of scanning all PIDs in the ECU? I loaded the Torque Scan plugin but that only seems to scan known PIDs.

I have not tried the “Allow plugins full access” option as it worries me that something may be inadvertantly altered.

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: October 31, 2013 (GMT)

Try running the pid scanner from
Torquescan menu.

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: October 31, 2013 (GMT)

Thanks. Done that but it now seems the ECU does not use the generic Ford PIDs.

Oh well. Back to the drawing board!

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: November 3, 2013 (GMT)

Well I have now discovered that the ECU is, in fact, a Ford ECU but the ECU is heavily reprogrammed to take out ABS, traction control, electric windows, aircon etc. In fact the ECU is only used for engine control and whatever instruments may be controlled from the ECU.

I have done a scan and emailed it to myself. What I see is (I assume) only the results of the queries that gave a response.

Do I understand correctly that the extended PIDs that are likely to be of interest to me are the ones that respond to a command prefixed by 22?
For example:
Command: 220924 response:620924003FA0F4

If this is the case I have only 21 that responded to a command prefixed by 22. However this was done with the engine not running as I did not want to gas myself in a closed garage. I can always try on another occasion in the open. It would not be impossible for me to try the 21 PIDs to see if one of them gave me a response that I might expect for the idle air control.

If anyone with a lot of experience in this area would like to look at the list of PIDs that were the result of the scan I have no problem to post some or all of them.

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: November 3, 2013 (GMT)

Look for any which include 41…, 61…, or 62…
like you posted. (Mode 01, 21 and 22).

Responses which include 7F… are not successful.

You also should try headers for addressing like
616AF1 or C410F1.

In your example 620924 is the header and
00 3F A0 F4 are the data bytes. (Torque variables
A, B, C and D).

The fun part is figuring out how to interpret the
bytes… is it four single byte values or two two
byte values…

Checking these values with the engine cold will
help with temperature values as they should be
close to ambient temps. Then you can watch them
respond as the engine warms to running temps.

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: November 3, 2013 (GMT)

Thanks again. I think I am beginning to understand this.

Ok, so the below 2 examples are where the scan finds a PID but does not get a data response to the command Mode 24 and 21? (or at least responds that it can not respond to that mode?)
Command: 2401 response:7F2401FFFF12
Command: 2101 response:7F2101000011

The data bytes returned to all the mode 24 commands are FFFF12
and to the mode 21 commands are 000011

On the other hand If the scan does not get any response to Mode 24, 21, or 22 it is not reported in the email report (for the sake of reducing the size of the emailed log). Correct?

If so that seems to indicate that the only extended or custom PIDs in the ecu that I can interrogate are those 21 that respond to a mode 22 command. Those that responded with no data to the mode 24 and 21 commands seem to be standard OBD2 PIDs in any case that would already covered by the 01 or 02 mode commands in the standard Torque library.

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: November 3, 2013 (GMT)

Those responses began with 7F… so they
were unsuccessful. The bytes following
are codes as to why it was unsuccessful.

Post your 21 successful pids… maybe the pids
can be found on the web.

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: November 4, 2013 (GMT)

Here they are (Note engine not running):

Command: 220001 response:6200010007E1E1
Command: 220004 response:62000400
Command: 220009 response:62000980
Command: 220019 response:62001900FF
Command: 220100 response:62010000
Command: 220101 response:620101000B
Command: 220200 response:62020002
Command: 220900 response:6209001027
Command: 220924 response:620924003FA0F4
Command: 220979 response:620979FDD4
Command: 221100 response:62110001004005
Command: 221101 response:62110108
Command: 221104 response:62110400
Command: 221600 response:62160000
Command: 221601 response:62160100
Command: 221624 response:6216240048
Command: 221631 response:62163100
Command: 2216a9 response:6216A902
Command: 22c104 response:62C10404
Command: 22c124 response:62C12460
Command: 22c131 response:62C13100000000

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: November 4, 2013 (GMT)

220200 looks familiar… possibly used for DTC Count.
221624 might be CHT (in Ford predefined pid list)

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: November 4, 2013 (GMT)

I’ve been back to the car and done some more testing. Most of the PIDs in the above list don’t seem to do anything with the engine running. 0009 goes to lower values as the throttle is opened. I checked most of the others and there were no changes with RPM or aircon on or off.

Something strange however. I decided to enter “IAC – 1153 – Idle Air Control” again and with only formula A I ran a test to see if I got a raw data response. Much to my surprise I got a response with rapidly changing data. (The first time I tried it I did not get any result so maybe I made an error)

This was the test result:
Result for equation: 57.0
Command: 221153
Response: C4F11062115334E012

This was just the data captured in a screen shot and I did not have time to make a full observation but the last few bytes were changing rapidly. I can return to make some more tests tomorrow. 9 bytes of data is certainly not used just for giving a % value for the IAC.

Capp777

Member
Posts: 2993

Re: Idle Air Control
on: November 4, 2013 (GMT)

Try the standard % equation…
(A*(100/255))
(B*(100/255))
(C*(100/255))
for each variable to see if it yields
realistic data.

Note C410F1 is header.

C4F110621153 34 E0 12
First part is header and
Mode/Pid response and
last three bytes are data.

If it is a two byte value try..
(((A*256)+B)*(100/65535))
(((B*256)+C)*(100/65535))

((A*256)+B)/13107
((B*256)+C)/13107
A*0.0196
B*0.0196
C*0.0196
for volts?

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: November 4, 2013 (GMT)

Thanks. I missed the fact that the first few bytes were header information. Probably it was the last 3 bytes that I saw changing too. I will run the formulas on that captured data and see if the results make sense before trying another test on the car.

Gambalunga

Member
Posts: 11

Re: Idle Air Control
on: November 6, 2013 (GMT)

Thanks for all the help. I used the formula (A*(100/255)) and that seems to have given me the results I was seeking. I think the second two bytes may refer to voltage but could also be something totally unrelated to IAC.

I also ran another PID scan with the engine running and it rather looks as though the scan is not working correctly as it did not return a result (at least in the emailed results) for Command: 221153 even though I am using it.

homerscj8

Member
Posts: 1

Re: Idle Air Control
on: February 4, 2016 (GMT)

Looking for help to monitor iac position using torque pro. Engine is a 2001 Ls 5.3 l. New to the obd2 world. Have torque pro and elm327 installed and functional.

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