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SUBJECT

DATE

SPN 51/FMI 2 - All Years

February 2014

Additions, Revisions, or Updates
Publication Number / Title
DDC-SVC-MAN-0084

Platform

Section Title

DD Platform SPN 51/FMI 2 - All Years

All information subject to change without notice.

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Copyright © 2014 DETROIT DIESEL CORPORATION

Change
Entire procedure updated.

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2 SPN 51/FMI 2 - ALL YEARS

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SPN 51/FMI 2 - ALL YEARS

This diagnostic is typically Intake Throttle Position Deviation Error.
This code sets when the intake throttle valve position has a 30% deviation from the position commanded by the Motor
Control Module (MCM) when the engine coolant temperature is above 60°C (140°F).
Table 1.
SPN 51/FMI 2
Description

Intake Throttle Position Deviation Error

Monitored Parameter

Intake Throttle Valve

Typical Enabling Conditions

Engine rpm = 600 rpm or higher, coolant temperature is less than
140°F

Monitor Sequence

None

Execution Frequency

Continuous when enabling conditions met

Typical Duration

Five Seconds

Dash Lamps

MIL, CEL

Engine Reaction

10% Derate

Verification

Engine rpm = 600 rpm or higher

Possible causes:
• Faulty ITV motor
• Faulty ITV position sensor
Check as follows:
NOTE: With the new strategy when the ignition key is turned on, the Intake Throttle Valve (ITV) will cycle two full
times, then the ITV will be commanded short increments when the key is turned on.
1. Turn the ignition OFF. Go to step 2.
2. Remove the hose from the Charge Air Cooler (CAC) to the ITV. Go to step 3.
3. Physically move the flap from stop to stop. Is there any binding or clicking noise present when the flap is physically
moved?
a. Yes; replace the ITV. Refer to section "Removal of the Intake Throttle Valve and Adaptor". Verify repair.
b. No; Go to step 4.
4. Connect Diagnostic Link™. Go to step 5.
5. Turn the ignition ON, (key ON, engine OFF). Go to step 6.
6. Using DiagnosticLink™, command the Intake Throttle Valve fully open and fully closed while watching the ITV flap
(Service Routines > Intake Throttle Valve). Does the ITV butterfly valve fully close and fully open when commanded?
a. Yes; Go to step 7.
b. No; replace the ITV.
7. Using the Air Intake Throttle service routine, command the ITV to 20% while monitoring the ITV actual position. Is
the actual valve position within +-5% of the commanded position?
a. Yes; Go to step 8.
b. No; replace the ITV. Refer to section "Removal of the Intake Throttle Valve and Adaptor". Verify repair.
8. Command the ITV to 50% while monitoring the ITV actual position. Is the actual valve position within +-5% of the
commanded position?
a. Yes; Go to step 9.
b. No; replace the ITV. Refer to section "Removal of the Intake Throttle Valve and Adaptor". Verify repair.
9. Command the ITV to 90% while monitoring the ITV actual position. Is the actual valve position within +-5% of the
commanded position?

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All information subject to change without notice.

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10.
11.

12.

13.
14.
15.

a. Yes; Go to step 10.
b. No; replace the ITV. Refer to section "Removal of the Intake Throttle Valve and Adaptor". Verify repair.
Turn the ignition OFF. Go to step 11.
Disconnect and inspect the ITV 5-pin connector. Are there any damaged pins, spread pins or the retainer clip missing?
a. Yes; repair as necessary. Verify repair.
b. No; Go to step 12.
Measure the resistance across pins 4 and 5, component side, of the ITV motor connector. Is the resistance less than 10
ohms?
a. Yes; Go to step 13.
b. No; replace the ITV due to a shorted motor. Refer to section "Removal of the Intake Throttle Valve and
Adaptor". Verify repair.
Install a test Motor Control Module (MCM).
Start and run the engine until the coolant temperature is above 60°C (140°F). Go to step 15.
Road test the vehicle. Is code SPN 51/FMI 2 still present?
a. Yes; replace the ITV. Verify repair.
b. No; replace the MCM. Verify repair.

All information subject to change without notice.

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Copyright © 2014 DETROIT DIESEL CORPORATION

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