IK1900228 ­ Air Conditioning Diagnostics

Page 1 of 6

AUSTRALIA, BRAZIL, CANADA, CHILE,
COLOMBIA, UNITED STATES, MEXICO,
NICARAGUA, PERU, PUERTO RICO, NEW
ZEALAND, PANAMA

Document
IK1900228
ID:

Availability:
Major
System:
Current
Language:
Other
Languages:

ISIS, FleetISIS

Revision:

2

ACCESSORIES

Created:

8/18/2014

English

Last
Modified:

10/28/2014

NONE

Author:

Kevin
Kochanek

Viewed:

461

Countries:

Less Info
Coding Information

Hide Details

Copy Link

Copy Relative Link

Bookmark

Add to Favorites

Print

Provide Feedback

View My Bookmarks

Helpful

Not Helpful

2

0

Title : Air Conditioning Diagnostics
Applies To : Post 2010 NGV

CHANGE LOG
10/28/2014 - Author updated for feedback purposes
10/1/2014 - Updated with new IKnow likns.
9/8/2014 - Updated SRT, special tools and coding.
8/05/2014 - Initial Article Release.




DESCRIPTION
This document addresses A/C issues on the following 2010 to 2014 vehicles with a BCM:
The following procedures will guide the user through common failure areas, diagnostic tools, SRTs, and warranty filing.

SYMPTOMS:
No cold air, not cold enough, or no air flow though vents.

Diagnostic Trouble Codes:
SPN

FMI

DESCRIPTION

2609

16

A/C High Pressure Protection

1079

1

5 volt sensor supply below normal

3985

9

A/C Control Head Circuit Failed To
Communicate With Body Controller

1552

2

A/C Control Head Temperature Mix DM1

3981

2

A/C Control Head Mode Fault DM1

3984

2

A/C Control Head Air Inlet DM1

2058

9

Rear A/C Data Link Communication
Failure

2058

14

Rear A/C Data Link Communication
Failure

3982

2

A/C Rear Blower Speed Control Switch
Error

3983

2

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014

IK1900228 ­ Air Conditioning Diagnostics

Page 2 of 6

Rear A/C Temperature Control Switch
Error
520465

2

A/C Control Head Multiple Motor Faults

Customer Observations or Concerns:
- Malfunction Indicator Light (MIL)

- No Cab A/C
- Not blowing cold enough
- No air flow though vents.
­ No Rear A/C
- Inoperative MaxxPro No Idle A/C System

SPECIAL TOOLS
Tool Description

Product
Number

Robinair A/C Machine or
equivalent

34988

Comments

Instructions

Used for Recover, Vacuum, and Performance test A/C
system

Tools Resource Center

SERVICE PARTS INFORMATION
Please see likes below for parts information as this article covers multiple models.

Parts Catalog
Parts Review

PROCEDURE OVERVIEW
Note:Do not start engine until steps 2-4 have been completed. If the engine has been run recently, allow the vehicle to sit for
one hour to allow system pressures to stabilize.

Before starting to diagnose the problem, it is important to consider the following:
•
•
•

Are there A/C related AFC’s open?
Was the vehicle recently in for an A/C repair in which the system was not properly filled or serviced?
Have there been recent A/C repairs and a fault code not cleared?

If the A/C issue is known (blown off hose, visible dye, inoperative blower motor) go directly to the respective steps or iKNow articles listed
below. Otherwise, go to step 1.

•
•
•
•
•

IK1900226 A/C Control Head Issues
IK1900225 A/C Mechanical Pressures diagnostics
IK1900223 A/C Sensor/ Electronic Issues
IK1900198 12V-No Idle HVAC Unit
IK1900227 Rear A/C Electrical and Mechanical Diagostics

DIAGNOSTIC STEPS
1 Customer Interview
Review the Repair Order to determine the following:
•

•

What is the A/C System doing specifically? (No
cold air, not cold enough, no air flow at vent, or no
defrost?
When does the concern occur? Vehicle
stationary, when idling overnight, or going down
the road?

Decision
Yes, cab A/C works correctly
but rear A/C does not: Go to
step 7.
Yes, concern is with MaxxPro
No­Idle HVAC unit: Go to
IK1900198
No: Go to step 2.

https://evalue.internationaldelivers.com/service_kb/DocTool/ArticleViewer.aspx?ControlI...

11/3/2014

IK1900228 ­ Air Conditioning Diagnostics

•
•

•
•

Page 3 of 6

Is the problem intermittent, or happen
consistently?
Have you had the vehicle serviced recently?
When and where? Was there an A/C related
service performed during that service?
Does issue concern the passenger compartment,
the sleeper, or both?
If equipped with a No-Idle system does the issue
only happen when utilizing the No­Idle System?

Is the problem confined to the rear A/C system while the
Cab A/C works correctly?
Is the problem confined to the operation or performance of
the MaxxPro No Idle system?

2
Preliminary checks
Note:Do not start engine until steps 2-4 have been
completed. If the engine has been run recently, allow the
vehicle to sit for one hour to allow system pressures to
stabilize.

Decision
Yes: Repair as necessary.
Restore system to operational
condition and operate the A/C
system to determine if the
complaint was corrected.

Perform a visual check of the A/C system to verify that no
obvious problems are present. With the engine off, inspect the
following items:
•
•
•
•
•
•
•
•
•
•
•
•
•
•

Compressor and clutch mounting