CEL and Inlet air temperature -40 degrees F

rmfurzeland · 11-04-2011, 12:14 PM

I have had a number of CEL problems with codes P1617, P1117 and P0600 popping up. Have replaced the battery but still an issue.
Took it to a local Ferrari "specialist" and they saw inlet temperature of -40 degrees F on a generic OBDII scanner (MAcTools) with the engine running. On my home scanner I can see the same reading of -40 in the freeze data with the error code P1617.
I have checked the air inlet sensor and it seems to give the correct variable resistance in the range 3000 - 500 ohms as the temp. increases to 110 degrees F, I see 5V reference at the connector and the earth continuity is fine.
So is this a red herring? Any other checks I can do? or I am seeing voltage spikes due to other issues?
Thanks
Ron Furzeland

tazandjan · 11-04-2011, 02:46 PM

Ron- It is hard to believe there is any temperature of -40F, which is also -40C, anywhere in the intact tract of a Ferrari not above the Arctic Circle. Something is amiss.

rmfurzeland · 11-04-2011, 04:23 PM

Hi Taz,
Minus 40 means that the resistance reading of the air intake sensor is at its highest but when I diconnect the connector and measure the sensor I see 720 ohm on my digital voltmeter and plus 110 degrees on my infrared thermometer.
This fits on the standard NTC chart so sensor looks good.
Wiring looks good since I see 5V at the sensor connector and one connector shows continuity to earth.
Puzzled,
Ron

Ferraridriver · 11-14-2011, 05:10 PM

I just installed the Garmin EcoRouteHD in my 550 and I see -40F inlet air temp as well. no trouble codes though.

tazandjan · 11-14-2011, 06:14 PM

Ron, Dave- Learn something new every day. 40 F differential, not absolute.

Brian may be able to help.

cribbj · 11-14-2011, 06:31 PM

I also routinely see the -40 from various temp sensors on my OBDII PC software. It'll show -40 one scan, then the value will be normal on the next scan. No CEL's either, so I just chalk it up to bad data transfer?

rmfurzeland · 11-14-2011, 06:49 PM

Thanks guys, that's reassuring, so basically the default value is -40 for temperature if the data transfer fails or if Ferrari ECUs are not "open" to generic scanners.
Over the weekend I got a reading of 109 degrees instead of -40 for inlet air, so thats good, but guess what , the coolant temperature reads -40 now, before it was over 100. So data transfer seems hit and miss.
Lesson, dont trust generic scanners for "live data" values.
Thanks,
Ron

Brian · 11-14-2011, 07:06 PM

Ferrari was exempted from many EPA requirements prior to 1/1/02 under limited manufacturer status so cars built prior do not always show what some expect is required info through the OBD plug. Limited manufacturer status expired for all motor vehicles on that date.

Also the OBD plug is required to show faults but not all data. Since Ferrari uses 2 engine management units, 1 left and 1 right, much of the left bank data is not available to generic equipment as it is the slave side. What you see is faults for left and right but data for right.

I have no idea what is normal to see or not see via generic scanners because I don't use them.

rmfurzeland · 11-15-2011, 08:03 PM

Hi Brian,
Yes, my 550 is year 2000 so probably exempt from later OBDII regulations. My scanner (clone of Equus 3140 Innova) claimed to be able to read CAN (Control Area Network) so I had hoped it could read master and slave ECUs but it seems not to work for the 550. Ferrari of Houston did do the earth pin update to the OBDII socket
I have just seen the wiki article on OBDII it mentions -40 (degrees C?) as a minimum temperature, see the table in
OBD-II PIDs - Wikipedia, the free encyclopedia

Regards,
Ron

11-04-2011, 12:14 PM	#1
rmfurzeland Owner Join Date: Oct 2011 Location: Houston, TX Ferrari Life Posts: 33 Name: Ron Furzeland	CEL and Inlet air temperature -40 degrees F I have had a number of CEL problems with codes P1617, P1117 and P0600 popping up. Have replaced the battery but still an issue. Took it to a local Ferrari "specialist" and they saw inlet temperature of -40 degrees F on a generic OBDII scanner (MAcTools) with the engine running. On my home scanner I can see the same reading of -40 in the freeze data with the error code P1617. I have checked the air inlet sensor and it seems to give the correct variable resistance in the range 3000 - 500 ohms as the temp. increases to 110 degrees F, I see 5V reference at the connector and the earth continuity is fine. So is this a red herring? Any other checks I can do? or I am seeing voltage spikes due to other issues? Thanks Ron Furzeland

11-04-2011, 02:46 PM	#2
tazandjan Owner Elite Member Join Date: Aug 2011 Location: Albuquerque, NM Ferrari Life Posts: 3,603 Name: Terry H Phillips	Ron- It is hard to believe there is any temperature of -40F, which is also -40C, anywhere in the intact tract of a Ferrari not above the Arctic Circle. Something is amiss. Taz Terry Phillips Present: 575M 135171 Past: Dino 246 GT 02984, 365 GTB/4 14009, 308 GTS 25125 Every day I look around, and if nobody is shooting at me, it is a pretty good day.

11-14-2011, 06:14 PM	#5
tazandjan Owner Elite Member Join Date: Aug 2011 Location: Albuquerque, NM Ferrari Life Posts: 3,603 Name: Terry H Phillips	Ron, Dave- Learn something new every day. 40 F differential, not absolute. Brian may be able to help. Taz Terry Phillips Present: 575M 135171 Past: Dino 246 GT 02984, 365 GTB/4 14009, 308 GTS 25125 Every day I look around, and if nobody is shooting at me, it is a pretty good day.

11-14-2011, 06:31 PM	#6
cribbj Owner Elite Member Join Date: Apr 2010 Location: Houston Ferrari Life Posts: 737 Name: John	I also routinely see the -40 from various temp sensors on my OBDII PC software. It'll show -40 one scan, then the value will be normal on the next scan. No CEL's either, so I just chalk it up to bad data transfer? '99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084 High mileage, low compression, and missing on a few cylinders.....just like my cars.

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11-04-2011, 04:23 PM	#3
rmfurzeland Owner Join Date: Oct 2011 Location: Houston, TX Ferrari Life Posts: 33 Name: Ron Furzeland	Hi Taz, Minus 40 means that the resistance reading of the air intake sensor is at its highest but when I diconnect the connector and measure the sensor I see 720 ohm on my digital voltmeter and plus 110 degrees on my infrared thermometer. This fits on the standard NTC chart so sensor looks good. Wiring looks good since I see 5V at the sensor connector and one connector shows continuity to earth. Puzzled, Ron

11-14-2011, 05:10 PM	#4
Ferraridriver Owner Elite Member Join Date: Aug 2009 Location: SF Bay Area USA Ferrari Life Posts: 63 Name: Dave	I just installed the Garmin EcoRouteHD in my 550 and I see -40F inlet air temp as well. no trouble codes though.

11-14-2011, 06:49 PM	#7
rmfurzeland Owner Join Date: Oct 2011 Location: Houston, TX Ferrari Life Posts: 33 Name: Ron Furzeland	Thanks guys, that's reassuring, so basically the default value is -40 for temperature if the data transfer fails or if Ferrari ECUs are not "open" to generic scanners. Over the weekend I got a reading of 109 degrees instead of -40 for inlet air, so thats good, but guess what , the coolant temperature reads -40 now, before it was over 100. So data transfer seems hit and miss. Lesson, dont trust generic scanners for "live data" values. Thanks, Ron

11-14-2011, 07:06 PM	#8
Brian Owner Elite Member Join Date: Jul 2005 Location: Northern California Ferrari Life Posts: 859 Name: Brian Crall	Ferrari was exempted from many EPA requirements prior to 1/1/02 under limited manufacturer status so cars built prior do not always show what some expect is required info through the OBD plug. Limited manufacturer status expired for all motor vehicles on that date. Also the OBD plug is required to show faults but not all data. Since Ferrari uses 2 engine management units, 1 left and 1 right, much of the left bank data is not available to generic equipment as it is the slave side. What you see is faults for left and right but data for right. I have no idea what is normal to see or not see via generic scanners because I don't use them.

11-15-2011, 08:03 PM	#9
rmfurzeland Owner Join Date: Oct 2011 Location: Houston, TX Ferrari Life Posts: 33 Name: Ron Furzeland	Hi Brian, Yes, my 550 is year 2000 so probably exempt from later OBDII regulations. My scanner (clone of Equus 3140 Innova) claimed to be able to read CAN (Control Area Network) so I had hoped it could read master and slave ECUs but it seems not to work for the 550. Ferrari of Houston did do the earth pin update to the OBDII socket I have just seen the wiki article on OBDII it mentions -40 (degrees C?) as a minimum temperature, see the table in OBD-II PIDs - Wikipedia, the free encyclopedia Regards, Ron