IK0800219 - Accelerator Position Sensor/IdleValidation Switch APS / IVS Diagnostics N... Page 1 of 5

SB-10044293-1044

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IK0800219
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ELECTRICAL SYSTEM

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Title: Accelerator Position Sensor/IdleValidation Switch APS / IVS Diagnostics NavPak™,
CEC equipped engine control systems
Applies To: All NavPak™, CEC equipped engines 1998 through 2003, including T444E,
DT466E and 530E engines. Vehicles included, but not limited to, would be:
2000,3400,3800,4000FBC,4000 8000, 4300,4400,7400,7500, 8500, CE Bus,RE Bus, FE Bus
1552 and 1652 SC, SFC Commercial Chassis, and 5000 vehicles.
DESCRIPTION

Two new APS sensors (Accelerator Position Sensor) have been developed and released for use with pre-2010
emissions International Engines. The new sensors listed below contain "non-contact" hall-effect idle validation
sensors. This replaces the open/closed IVS switches in the old sensors . As a result of this new design, the normal
resistance measurements performed for the potentiometer and idle validation switch on the previous "contact'
sensor are no longer applicable. A technician can continue to perform resistance measurement tests on
the engine harness with the sensor unplugged (open circuit), but should rely solely upon the voltage measurement
tests, with a breakout harness installed, at the ECM and APS sensor, and the new sensor connected.
SYMPTOMS





APS/ IVS fault codes
Engine speed restricted to idle
Erratic automatic transmission operation
Engine warning lights illuminated

POSSIBLE DIAGNOSTIC TROUBLE CODES
T444E, DT466E, 530E, NavPak™ equipped vehicles

DTC MODULE DESCRIPTION
131 ECM

APS signal voltage out-of-range LOW . < 0.147 V for more than 0.35 seconds.

132 ECM

APS signal voltage out-of-range HIGH. > 4.55 V for more than 0.35 seconds.

133 ECM

APS signal in-range fault.

134 ECM

APS and IVS disagree.

135 ECM

Idle validation switch circuit fault

PARTS INFORMATION
Please refer to TSI letter 10-08-01 for parts details including cross reference information.

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IK0800219 - Accelerator Position Sensor/IdleValidation Switch APS / IVS Diagnostics N... Page 2 of 5

Follow link https://evalue.internationaldelivers.com/service/tsis/100801_1.xml
DIAGNOSTICS
There can be various conditions that can cause APS/IVS related issues. As with any performance related fault, a thorough description
of the issue, from the operator is critical.






Is the fault sensitive to road conditions, such as rough terrain, hills, etc ?
Is the fault temperature sensitive ?
Does the fault occur, when coming to a stop, or when accelerating or cruising ?
Do any other faults occur at the same time, such as loss of dash cluster, or other in cab accessories ?
Are there faults regarding the IAT (intake air temperature) sensor, BAP(barometric air pressure sensor)?

If any circuit issues are suspected, a thorough visual inspection of all circuitry for shorts, and opens is critical, as intermittent issues
are usually caused by wiring faults. Any harness mounting points should be disassembled and inspected. Where harnesses pass by
sharp edges, or possible points of abrasion should be inspected and if required, repaired. On 4300, 4400, 7300, and 7400,
DT466E/530E , NavPak™ ECM equipped, vehicles chassis' several common harness contact points have been noted. The harness
passes by the drivers side edge, of the doghouse opening in the firewall. The harness runs very close to this area, and can cut, and
short the harness. At the left rear of the engine valve cover, is a P-clamp mounting of the harness. This clamp, and the
surrounding mounting area, can cause harness abrasion, and shorting. The harness is long enough, in these areas, to be relocated,
after the repair, to prevent recurrence.
On T444E, DT466E and 530E NavPak™ ECM equipped chassis', when inspecting the ECM connector, remove the orange rubber
seal, located in the ECM, being careful to not damage/bend any pins. This seal can mask evidence of corrosion in the ECM. Removal
of the red locks in the ECM connector, for thorough terminal inspection, is also recommended.
Whenever connector inspection has been performed, and tested satisfactory, always apply a light coating of dielectric grease upon
reconnection, being careful to properly lock connectors.
On 2000,3400,3800,4000FBC,4000 and 8000 models, the metal pedal assemblies can wear over time, causing a timing
issue between the APS and the IVS signals. A worn pedal can often be tested by pulling up on the accelerator pedal, with the
ignition switch on. If faults codes become active, the pedal assembly is most likely the cause.
If idle validation faults are an issue, testing the ignition voltage supply to the sensor should be performed. Opens, short, corrosion,
etc. can interfere with the IVS operation.
COMPONENT/FUNCTION DESCRIPTION

The Accelerator Position Sensor (APS) is a potentiometer sensor. When the APS receives a 5V reference signal
and a ground from the Electronic Control Module (ECM), a linear analog voltage signal will indicate a demand for
power.
The Idle Validation Switch (IVS) provides 0 or 12 Volts to the ECM as a signal to verify the pedal idle position.
Fault Detection and Management
Detected malfunctions of the APS or IVS sensor circuit will illuminate the WARN ENGINE lamp.
If the ECM detects an APS signal Out of Range High or Out of Range Low, the engine will ignore the APS signal
and operate at low idle.
When differences between IVS and APS are detected, the ECM sets an IVS Diagnostic Trouble Code and limits
the APS command to 50%.
If differences between the IVS and APS are detected, but the ECM cannot discern an APS or IVS Diagnostic
Trouble Code, the engine will operate at low idle only.
Extended Description
International® electronic engines use an electronic accelerator pedal assembly that includes an Accelerator
Position Sensor (APS) and an Idle Validation Switch (IVS). The APS and IVS are integrated into one component
mounted on the accelerator pedal. The accelerator pedal assembly is serviceable to the extent that the APS/IVS
switch can be replaced without replacing the complete assembly.
Accelerator Position Sensor (APS)
The ECM sends a regulated 5V signal through the ECM black chassis connector terminal 3 to APS connector
terminal C. The APS returns a variable voltage signal (depending on pedal position) from the APS connector
terminal A to the ECM at terminal 8. The APS is grounded from connector terminal B to the ECM signal ground

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IK0800219 - Accelerator Position Sensor/IdleValidation Switch APS / IVS Diagnostics N... Page 3 of 5

terminal 11.
APS Auto-Calibration
The ECM determines the lowest and highest pedal positions by reading and storing the minimum and maximum
voltage levels from the APS. In this manner the ECM auto-calibrates the system for maximum pedal sensitivity.
The ECM auto-calibrates when the key is ON, but when the key is OFF, these values are lost. When the key is ON
again, this process starts over. When the pedal is disconnected (or new one installed), the pedal does not need
calibration, since calibration happens when the key is ON.
Idle Validation Switch (IVS)
The ECM expects to receive one of two signals through the ECM black chassis connector (terminal 27) from
APS/IVS connector terminal D:
·

0V when the pedal is in the idle position.

·

12V when the pedal is depressed.

The Idle Validation Switch receives 12V voltage from the ignition fuse. When the pedal is not in the idle position
(throttle applied), the IVS supplies a 12V signal to the ECM.
The ECM compares APS/IVS inputs at terminals 8 and 27 to verify that the pedal is in the idle position. If the APS
signal at terminal 8 indicates throttle is being applied, the ECM expects to see 12V at IVS terminal 27. If the APS
signal at terminal 8 indicates idle, the ECM expects to see 0V at the IVS terminal 27.
ECM Diagnostics
When the ignition is ON, the ECM continuously monitors the APS/IVS circuits for expected voltages. The ECM
also compares the APS and IVS signals for differences. If the signals are not what the ECM expects to see, the
ECM sets Diagnostic Trouble Codes.
TROUBLESHOOTING
NOTE:
When performing diagnostic tests, be sure to refer to the correct circuit diagram manuals, found on ISIS, for the vehicle you are
working on. If working on a vehicle built before October 1, 1998, you will need to refer to a paper/hard copy manual, as they are not in
electronic format on ISIS®. However, the electronic versions, found on ISIS®, of the Engine Diagnostic manuals, and Electronic
Control System Diagnostic forms will also provide you with circuit diagrams.

ZTSE 4486 - APS /IVS Breakout Tee
CIRCUIT DIAGRAMS

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IK0800219 - Accelerator Position Sensor/IdleValidation Switch APS / IVS Diagnostics N... Page 4 of 5

NavPak™ Controller APS /IVS Circuit
Connector Voltage Checks
(Check with Sensor Connector disconnected, and Ignition Key On)
Test Points
Specification
Comments
If
greater
than
0.25V,
signal
is
shorted
to VREF or B+.
A to GND
< 0.25V
B to GND
C to GND

0V
5 ± 0.5V

D to GND

< 0.25V

F to GND

12V ± 1.5V

Signal ground no voltage expected.
Voltage > spec, wire shorted to B+
Voltage > 0.25V, IVS signal wire shorted to VREF or B+
Voltage < 10.5V check circuit for open or resistance.

Harness Resistance Checks
(Check with breakout box installed on Chassis Harness and ZTSE-4485 - APS/ IVS Break Out Tee Connected to
Chassis Harness Only)
Test Points
Specification
Comments
#8 to A
< 5 ohms
Resistance from 60 pin connector to harness connector - APS signal.
#11 to B
< 5 ohms
Resistance from 60 pin connector to harness connector - Signal ground.
Resistance from 60 pin connector to harness connector - VREF.
#3 to C
< 5 ohms
#27 to D

< 5 ohms

F17 to F

< 5 ohms

Resistance from 60 pin connector to harness connector - IVS signal.
Resistance from VIGN. power to harness connector.

Operational Voltage Checks
(Check with ZTSE-4485 - APS/ IVS Break Out Tee installed and APS/IVS sensor connected)
Operational Signal Checks
APS Test Points
IVS Test Points
(Check with breakout box installed on ECM and Engine
(+) #8 to (-) #11
(+) #27 to (-) #11
Harness)
Position
Voltage
% APS
Voltage
% APS
Comments
Low Idle 0.64 - 0.66V
0%
0V
0%
IVS toggles just off idle.
High Idle 3.84 - 3.86 V 98 - 102% 12 ± 1.5 V 98 - 102%

NOTE:
If any of the circuit readings are not within the required specifications, keep in mind, that the IAT (Intake Air Temp.) sensor, is spliced
with the signal ground and BAP (Barometric Air Press.) sensor circuits are spliced with the 5 volt reference circuits, of the APS/IVS.
These circuits should also be inspected, as they can affect the APS/IVS function/readings.

NOTE:
When performing diagnostic tests, be sure to refer to the correct circuit diagram manuals for the vehicle you are
working on.

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IK0800219 - Accelerator Position Sensor/IdleValidation Switch APS / IVS Diagnostics N... Page 5 of 5

If all circuit and operational tests have been performed, and all wiring/components have been inspected and are deemed to
be satisfactory, yet the issue is still not resolved, open a tech service case file for further diagnostic assistance.
ADDITIONAL RELATED IKNOW DOCUMENTS:
ik0800218 3-Box equipped vehicles
ik0800223 DLCII equipped vehicles
ik0800226 MaxxForce® equipped vehicles
ik0800227 MaxxForce® 11 and 13 equipped vehicles
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You received the following feedback From: U00JFG2 - John Gislason Email Address: SMTP:
{John.Gislason@Navistar.com}John.Gislason@Navistar.com Feedback: Link for TSI 10-08-01 is dead. It is also
5/7/2012
IMPERATIVE that the correct sensor P/N be used for the engine installed, the pedal assembly may, or may not, have the 9:28:07 AM
correct sensor installed as received.

Copyright © 2012 Navistar, Inc.

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