Click here to make tpub.com your Home Page

Page Title: Engine Speed/Timing Sensor Circuit - Test
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home


   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 

TM 9-2320-312-24-2
Troubleshooting Section
The engine uses two engine speed/timing sensors.
G. Access the special test "Engine Running Output"
Both of the engine speed/timing sensors detect
on ET.
the reference for engine speed and timing from
a unique pattern on the camshaft gear. The ECM
H. Cycle the special test "Engine Running Output"
counts the time between pulses that is created by
to "Active" and to "Not Active" and watch the
the sensor as the gear rotates in order to determine
voltage test lamp.
rpm. The ECM remembers the pattern of the pulses.
The ECM uses the pattern of the pulses in order to
I. Stop the special test.
determine the position of the crankshaft.
Note: A multimeter can not be used in place of the
When the timing has been established, the ECM
voltage test lamp when the ECM outputs are being
triggers each injector in the correct firing order at
tested.
the correct time.
Expected Result:
The actual timing and duration of each injection is
based on engine rpm and load. If the engine is
The voltage test lamp turns ON when the test is
running and the signal from one of the camshaft
active. The voltage test lamp turns OFF when the
position sensors is lost, no noticeable change in
test is not active.
engine performance will be noticed.
Results:
The engine will start and the engine will run when
Yes The ECM is OK. The problem is in the
only one sensor signal is present from either of the
sensors. The loss of the signal from both of the
vehicle wiring. Inspect the vehicle wiring and then
sensors during engine operation will result in the
repair the vehicle wiring. Otherwise, send the
termination of injection and the shutting down the
vehicle to the OEM dealer for repair. Verify that
engine by the ECM. The loss of the signal from
the original condition is resolved. STOP.
both of the sensors during start-up will prevent the
No Temporarily connect a test ECM. Use the
engine from starting.
"Engine Running Output Special Test" on ET to
Both sensors are magnetic sensors. The two
check the ECM. If the problem is resolved with
sensors are not interchangeable. Do not switch
the test ECM, install the suspect ECM. If the
the positions of the sensors. The two sensors
problem returns with the suspect ECM, replace
must be replaced as a pair. If the sensors are
the ECM. Verify that the repair eliminates the
replaced, a timing calibration is not necessary for
problem. STOP.
the engine. Timing calibration is only necessary
after replacing an ECM that will not communicate.
i01857873
Engine Speed/Timing Sensor
Circuit - Test
SMCS Code: 1912-081
System Operation Description:
Use this procedure under the following situation:
Use this procedure to troubleshoot the system only
under the following conditions:
There is an active diagnostic code or an easily
repeated diagnostic code that is associated with
the engine speed/timing circuit.
You have been referred to this test from
Troubleshooting, "Troubleshooting without a
Diagnostic Code".
g00864785
Illustration 90
The following background information is related
Left side engine view (typical view)
to this procedure:

Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business