ECM Snapshot

TM 9-2320-312-24-2

Troubleshooting Section

Adjustment of ECM Date/Time

ECM Diagnostic Clock

Clock

The diagnostic clock should not be confused

with the ECM Date/Time clock. The diagnostic

Before adjusting the ECM Date/Time Clock on

clock records the actual hours of the ECM under

a vehicle, ask the owner/operator if the time

power. The information from the diagnostic clock

stamped information should be recorded. After the

is used in order to log occurrences of diagnostic

time stamped information is recorded, clear this

codes and occurrences of event codes. Logged

information before adjusting the ECM Date/Time

diagnostic codes and logged event codes display

Clock. This is a very important step if the adjustment

the diagnostic clock hour of the first occurrence

of the clock is a big adjustment. This will prevent

and the last occurrence and the total number

unnecessary confusion if someone else views the

of occurrences. The diagnostic clock does not

information at a later date.

represent actual engine hours. The clock increments

any time of the ECM under power. This happens

Occurrence of Time Stamped

when the engine is running or when the engine is

not running. Actual engine running hours (Total

Information

Time) can be obtained from the menu for Current

Totals of Electronic Technician (ET).

When the time stamped information is being viewed,

remember that the vehicle may be based in a

different time zone. Also remember the following

i01642339

two possibilities:

ECM Snapshot

Someone may have incorrectly set the clock.

SMCS Code: 1901

No one ever set the clock.

The ECM can record a snapshot of the engine

parameters and vehicle parameters. The snapshot

Compare the electronic control module's current

records the parameters for a period of 13 seconds

time of day to the time stamped information in the

that surrounds the event. The event is either a

ECM in order to determine the amount of time

diagnostic code or an external trigger.

that has passed since the occurrence of the time

stamped event. DO NOT REPLACE AN ECM

BECAUSE OF AN INCORRECT TIME OF DAY. The

Use Of Snapshot

following example indicates the proper use of the

clock.

Use snapshots ONLY to help determine

engine/vehicle operating conditions when an

Proper Use of ECM Date/Time

intermittent problem occurs. If an intermittent

diagnostic code is causing problems, use the

Stamped Information

snapshot data. Snapshot data can be used to

determine whether the problem seems to occur

Caterpillar Electronic Technician (ET) indicates that

under specific circumstances. The following list of

a diagnostic code occurred. The 190-00 Engine

conditions is an example of some of the specific

Overspeed Warning occurred on 19 November 1998

circumstances:

at 10:30:46. ET also indicates that the current time

of day in the ECM is 24 November 1998 at 11:20:58.

Engine rpm

This indicates that the problem occurred in the

past (approximately one week and 50 minutes).

Ranges of vehicle speed

Do not compare the electronic control module's

Ranges of coolant temperature

time of day to the current time of day at your

location. If the electronic control module's time of

Use this data to attempt to duplicate these

day differs significantly from the current time of

conditions with the vehicle and get the code to

day (wrong month), ensure that the important time

reoccur.

stamped information is recorded. After recording

the information, clear the code or the snapshot, and

then adjust the clock.