NHTSA ID Number: 10191855
Manufacturer Communication Number: TechTalk566265K
TSB/Document Date: 2021-05-07
Summary
Tech Talk discussion on 2019 m2 dd8 AC inop.
5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
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DTNA Solutions >» Discussions and Feedback > : Tech Talk > Re: 2019 m2 dd8 a/c inop
y “Matt_Welch
Wrench Turner
04-09-2021 11:46 AM
2019 m2 dd8 a/c inOpy Jump to solution
Vehicle Information
VIN: IFUBCXD27KHKJ8650 Mileage: 69337 miles
Model Year: 2019 Are you currently seeing this same issue
on other DTNA vehicles at your location?:
Make: FTL
no
Base Model: M2106
Model: M2 106 CONVENTIONAL CHASSIS
Vehicle Systems Involved
OTHER SYSTEM (A/C
pressure high, fan wont
engage)
2019 m2 dd8, ac compressor will cycle, building 450 on the high side, up to 60 on the low
side. Fanis never commanded on from ac. Fan will work if commanded with
input/output. | have not been able to monitor anything on the ac except the clutch. Cant
see blower, blend doors, evap temp, pressure switches, etc. using dl8 or service link.
Have tried test hvac module, test bhm, cpc, cgw. Verified correct ac charge. Blower
motor and all hvac module controls seem to work but cannot monitor.
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5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
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1Solution A
Vy Matt_Welch
Wrench Turner
04-14-2021 03:05 PM
(¥ CSC uploaded new cpc software to server, fan on at 300 psi for 180 seconds.
Thank you all for your help.
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5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
© Jon_Cecil
Gear Head
04-09-2021 04:52 PM
Have you inspected the fan cycling switch?
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W Talbert_Simonia
King Pin
04-10-2021 05:44 PM
Can you command the engine fan to come on with D/L ? If not that maybe you issue. If
you can need to see why it is not getting the command to come on.
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@[m)
rN W Michael_Palumbo
I KingPin
04-10-2021 06:57 PM
The AC fan cycle switch A22-45194-001 is in BOM 702. The part description indicates it
is aNC, Normally Closed switch.
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5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
The schematic GO6-83541-001 that shows the circuit is in BOM 276. The schematic
indicates the switch is supposed to open at 300psi.
With this information | would look for the switch being stuck closed.
The quickest test would be to disconnect the switch to create an open circuit. If the fan
comes on, it is the switch.
If the switch is not stuck closed then wire 440Y could be shorted to ground.
Edited to add the following:
Your CPC and or MCM parameters could have been changed inadvertently. Compare
your CPC and MCM parameters to 16TS-25
Whether you think you can or you think you can't, you're right. — Henry Ford
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oo Steve_Reppard
Piston Head
04-12-2021 10:44 AM
What does fan status read during a/c operation? Does it ever change to a/c request?
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a onc;
J. Chris_Vanboom ® Top
Piston Head
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5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
04-13-2021 06:40 AM
S
This is an issue with a "hidden" parameter that cannot be viewed or changed witha
dealer version of DDDL. We have had several units with this same issue, you need to
phone CSC - they change a parameter on the server and you program CPC and/or MCM to
latest server settings and the problem is solved. The old Bulletin 161TS20 refers to same
issue on DD13
Chris VanBoom
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B WTS20.pdf
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yy Matt_Welch
Wrench Turner
04-13-2021 11:12 AM
| can command the engine fan with dl8. The fan status does not appear to ever show as
commanded on by ac. | have tried unplugging the ac switches, and jumping them, no
change with the fan. | have not checked the parameters with 16ts25, but i will check
them.
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WY Michael_Palumbo
—
King Pin
04-13-2021 12:52 PM
The AC controller does not command the fan on. The switch is found in the AC
section of partspro but the circuit for it is not. The schematic | previously
mentioned is in the fan section and it shows the circuit starts at the CPC, passes
through a firewall connector then through the switch to get to ground. The
switch is NC but will open at 300psi, therefor if the CPC never sees the circuit go
open, the CPC fill never command the fan on. You stated you have disconnected
the switch, which should have created an open for the CPC to detect. Have you
tested the circuit from the CPC to the switch, to see if it is shorted to ground?
Whether you think you can or you think you can't, you're right. — Henry Ford
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y “Matt_Welch
Wrench Turner
04-14-2021 11:01 AM
| have checked 440y for shorts to ground, no shorts. | have also checked the parameters
outlined in 16ts25, all ok. | have verified the switch measures OL when the ac pressure
reaches 300. The fan is commanded on by high cac out and coolant temps, still never
with ac.
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5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
an Chris_Vanboom
ik
Piston Head
04-14-2021 11:05 AM
In every one of the several cases where we have solved this same issue, we
contacted the CSC and they made a change on the server that we could not see.
After the change was made on the server and we programmed the CPC/MCM/ACM
with latest server settings the issue was fixed. Have you contacted the CSC?
Chris VanBoom
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yy Matt_Welch
Wrench Turner
04-14-2021 11:10 AM
| have not contacted csc yet. | have had similar issues with fan and ac on dd13 and dd15
that have the parameter/programming issues but not dd8
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5/5/2021 Solved: Re: 2019 m2 dd8 a/c inop - Page 2 - DTNA Solutions
x Chris_Vanboom
Piston Head
04-14-2021 11:11 AM
We have seen several of the exact same issue on DD8
Chris VanBoom
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Vy Matt_Welch
Wrench Turner
04-14-2021 11:25 AM
Just started acsc ticket
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Vy Matt_Welch
Wrench Turner
04-14-202103:05 PM
(¥Y CSC uploaded new cpc software to server, fan on at 300 psi for 180 seconds.
r
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