IK0800284

IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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IK0800284
Revision:
21
Major System: ELECTRICAL SYSTEM
Created:
5/16/2011
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Last
Modified:
11/20/2017
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Author:
Charles
Schroeder
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Title : Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
Applies To : Navistar N13 Engines and Cummins ISX Engines Cummins ISB, N9 and N10
Change Log
Dealers: Please refer to the change log text box below for recent changes to this article:
11/20/2017 - Updated diagnostic software to Navistar Engine Diagnostics™.
03/13/2017 - Added link to IK1200886 - Relocation of AAT Sensor to Mirror due to Fault Codes and Air Temp Flow Issues with Aftermarket Bumpers
as this relocation changes the wiring for the sensor.
02/24/2017 - Updated to correct author
08/12/2015 ­ Removed 2010 MaxxForce 11/13. Please refer to updated manual 0000001741.
06/22/2015 - Author updated for feedback purposes.
01/22/2015 - Add TranStar model
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
Table of Contents
Click on the items below to jump to each section:
Description
Cluster Circuit Diagrams
Symptom(s)
Sensor Location - Big Bore Engines
Special Tool(s) / Software
Sensor Location - Medium Duty Engines
Service Parts Information
Engine Sensor Circuit Diagrams (See NOTES below)
Engine Sensor Troubleshooting
Warranty Coding / SRT
Cluster Sensor Troubleshooting
Other Resources
Description
The Ambient Air Temperature Sensor provides information to the Engine and / or Cluster based on vehicle model and engine application. The
number of sensors used and location of each sensor also varies based on vehicle model and engine application. This article will help outline
the different installation options for this sensor.
On all SCR vehicles, the cluster will receive AAT Sensor data via J1939, 0595BTH, reducing the number of aat sensors from 2 to 1
on each SCR vehicle.
If unable to find AAT sensor in the mirror, check service portal for previous repairs. We have seen cases where the mirror head was
replaced and the sensor was not reinstalled properly.
If the sensor was relocated the mirror the wiring for the sensor will not match the schematic based on the vehicles build date.
Please refer to IK1200886 - Relocation of AAT Sensor to Mirror due to Fault codes and Air Temp Flow Issues with Aftermarket
Bumpers for more information.
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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Symptom(s)
Diagnostic Trouble Code(s) & Dashboard Indicator Light(s):
DTC / Light
Cummins Fault
Description
SPN 171 FMI 2
2389
AAT signal does not agree with other sensors
SPN 171 FMI 3
249
AAT signal out of range HIGH
SPN 171 FMI 4
256
AAT signal out of range LOW
Customer Observations or Concerns:
• MIL
• Engine performance may be reduced
• Unable to perform regen
( Return to Top )
Special Tool(s) / Software
Tool Description
Tool Number
Comments
Navistar Engine
Diagnostics™
EZ-Tech Software
Cummins INSITE
EZ-Tech Software
Instructions
( Return to Top )
Service Parts Information
Kit Description
Part Number
Quantity
Notes
Required
Sender, Ambient Temperature
3561562C1
1
( Return to Top )
Engine Sensor Troubleshooting
There are two ambient temperature sensors. The sensor located behind the cab along the left frame rail is the sensor the engine uses. To
confirm this, unplug the sensor and observe the cluster LCD display, it the reading stays the same, the correct sensor is unplugged. There is
also a sensor located at the front of the chassis that the gauge cluster uses for the temp display.
This article begins and discusses the Engine AAT Sensor, prior to and first. After August 23, 2013, Some SCR engines have the Engine AAT
sensor mounted in the driver side mirror head and alternatively the sensor could be mounted to the horn bracket. The location depends on
build date.
2013 Navistar N13 Diagnostics
FAULT CODE 171-2 ONLY
Step
Action
Decision
Update ECM Calibration
1
• Check Calibration Scorecard on Service Portal
• Use Electronic Service Tool (EST) to clear the fault code.
Repair Complete.
This code will be corrected with the new ECM Calibration
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2010 MaxxForce 11/13L Diagnostics
FAULT CODE 171-2 ONLY
NOTE: If the ECM is setting/logging code 171-2 and the sensor tests good DO NOT replace the sensor, there is a new calibration available
as of March 7, 2014 for EGR engines.
Step
Action
Decision
Update ECM Calibration
1
• Check Calibration Scorecard on Service Portal
• Use Electronic Service Tool (EST) to clear the fault code.
Repair Complete.
This code will be corrected with the new ECM Calibration
All Engines with Ambient Air Temp Sensor
FAULT CODE(s) 171-3 and 171-4 ONLY
Refer to the appropriate Engine or Chassis wiring schematic manual to ensure you are on the proper ECM connector and terminal.
Step Action
Measure Resistance of the sensor and compare to
the chart shown in Figure 1
1
Step Action
Measure voltage between ambient temperature
sensor connector cavity A and GND
No: Replace AAT Sensor
Decision
Yes: Go to step 3
• SPEC: 5 +/- 0.5 Vdc
Is voltage measurement in spec?
Step Action
Measure voltage between ambient temperature
sensor connector cavity A and cavity B
3
Yes: Go to step 2
• SPEC: Based on Ambient Temp
Is resistance measurement in spec?
2
Decision
No: Inspect wire from ECM to AAT sensor pin A for
open or short
Decision
Yes: Restore back to operational condition and
retest for fault code 171-3 or 171-4
• SPEC: 5 +/- 0.5 Vdc
Is voltage measurement in spec?
No: Inspect ZVR wire from ECM to AAT sensor pin
B for open or short
( Return to Top )
Cluster Sensor Troubleshooting
FAULT CODE(s) 171-3 and 171-4 ONLY
The instrument cluster, connector 1501 pin 9, sends a 5-volt source to the temperature sensor. As the voltage goes across the temperature
sensor it decreases, the amount of voltage drop depends on outside temperature. The reduced voltage then returns to the instrument cluster
on pin 8 of connector 1500. The instrument cluster turns the received signal into to the temperature shown on the display.
NOTE: The Electronic Gage Cluster display will replace temperature reading with two dashes (- -) if a fault is present with the Ambient
Temperature Sensor circuit.
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
Step Action
Measure Resistance of the sensor and compare to
the chart shown in Figure 1
1
• SPEC: Based on Ambient Temp
Page 4 of 13
Decision
Yes: Go to step 2
No: Replace AAT Sensor
Is resistance measurement in spec?
Step Action
Decision
Measure voltage between ambient temperature
sensor connector cavity A and GND
2
• SPEC: 5 +/- 0.5 Vdc
No: Inspect wire from cluster 1501-9 to AAT sensor
pin A for open or short
Is voltage measurement in spec?
Step Action
Decision
Measure voltage between ambient temperature
sensor connector cavity A and cavity B
3
Yes: Go to step 3
Yes: Restore back to operational condition and
retest for fault code 171-3 or 171-4
• SPEC: 5 +/- 0.5 Vdc
No: Inspect ZVR wire from cluster 1500-8 to AAT
sensor pin B for open or short
Is voltage measurement in spec?
AAT Sensor Temperature VS. Resistance Chart
Figure 1
Temp
Temp R Nom
-76F
-60C
1,410,910 1,267,349.9 1,554,470.1 10.175
R Min
R Max
+/- (%) Tol Nom
-58F
-50C
671,960
611,483.6
732,436.4
9
-40F
-40C
336,000
310,464
361,536
7.6
-22F
-30C
177,000
165,185.3
188,814.8
6.675
-4F
-20C
97,060
91,382
102,738
5.85
14F
-10C
55,319
52,483.9
58,154.1
5.125
32F
0C
32,654
31,225.4
34,082.6
4.375
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
Page 5 of 13
• Return to Troubleshooting Engine Sensor
• Return to Cluster Sensor Troubleshooting
( Return to Top )
Cluster Circuit Diagram(s)
IMPORTANT: Due to variations during vehicle production, be sure to select the most current wiring schematic manual, specific to the year
and model of the vehicle being serviced.
•
•
•
•
•
ProStar / LoneStar wiring for Cab Sensor
ProStar / LoneStar wiring for Cab Sensor with Front Axle Load Sensor
HPV wiring for Cab Sensor
HPV wiring for Cab Sensor with Front Axle Load Sensor
TerraStar wiring for Cab Sensor
The Cab Temperature Sensor is typically mounted near the front bumper or on the cooling package. If the sensor cannot be found verify the
wiring to the gauge cluster is present or that the outside air temp monitor feature as ordered on the truck.
Figure 2
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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Medium Duty Chassis Standard Mounting Location for Cluster Sensor
Figure 3
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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TerraStar Chassis only: The AAT sensor was relocated to the ABS ECU bracket May 2012
( Return to Top )
Sensor Location - Big Bore Engines
Big Bore Pre­SCR Engines and SCR Engine prior to August 2013:
The engine sensor is located on the left frame rail midway between the back of cab and front drive axle, or near the front drive axle. The
two photos below show both possible mounting locations (Figure 4 and Figure 5).
Figure 4
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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Figure 5
Big Bore Post August 2013 build w/SCR engine, driver's side mirror head (Figure 6):
Figure 6
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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ISX15 and N13 Alternate Location (Figure 7):
Figure 7
ISX15 and N13 Alternate Location PayStar / 9900i (Figure 8):
Figure 8
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( Return to Top )
Sensor Location - Medium Duty Engines
N9/10 and ISB engine platforms moved the Engine AAT to the driver mirror on August 8, 2014 (Figure 9):
Figure 9
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Location prior to August 8, 2014 on CE Bus
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
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( Return to Top )
Engine Sensor Circuit Diagram(s)
N13 ProStar built after May 2014
N13 ProStar built prior to May 2014 / MaxxForce 11/13
N13 PayStar / 9900i built after May 2014
N13 PayStar / 9900i built prior to May 2014 / MaxxForce 11/13
ISX15 ProStar built after May 2014
ISX15 ProStar built prior to May 2014
ISX15 PayStar / 9900i built after May 2014
ISX15 PayStar / 9900i built prior to May 2014
ISB built after May 2014
ISB built prior to May 2014
N9/N10 built after May 2014
N9/N10 built prior to May 2014
( Return to Top )
Warranty Coding / SRT
Warranty Claim Coding:
Group: 12000 - Engines
Noun: 160 - Sender, Ambient Temperature
Warranty Claim Coding:
Group: 08960 - Miscellaneous (Electrical)
Noun: 784 - Thermometer, Electronic
Standard Repair Time(s):
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IK0800284 ­ Ambient Air Temperature (AAT) Sensor Faults/Location/Diagnostics
Step
Description
Chassis
1
Ambient Air Temperature Sensor, Replace
ProStar
1
Air Temperature Display Sensor, Replace
All Models
Engine
Cummins ISX
Page 13 of 13
SRT
Hours
R08-8160S
0.3
A08-3240
0.5
Claim SRT Example:
Claim Comment Suggestion:
Special Requirement(s):
( Return to Top )
Other Resource(s)
• IK0800369 - 2006-2009 Cummins Active Fault 249 / 256 Ambient Air Temperature Sensor 1 Circuit
( Return to Top )
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