Storage of Snapshots in the ECM

TM 9-2320-312-24-2

Troubleshooting Section

Vehicle speed

If the owner loses the owner's customer

passwords, the owner will not be able to

Cruise status

program customer parameters. By Using factory

passwords, one can read customer passwords.

Brake switch

Then use those customer passwords to program

customer parameters.

Storage of Snapshots in the ECM

4. Clear Certain Diagnostic Codes

The ECM can store a maximum of two snapshots

The Diagnostic Code 190-00 that is Engine

that are triggered by a diagnostic code, two

Overspeed Warning requires the use of factory

snapshots that are triggered externally, and one

passwords in order to clear the code once the

quick stop snapshot. The snapshots are stored in

code has been logged. The Diagnostic Code

a circular buffer. The newest snapshot will replace

252-11 that is Incorrect Engine Software (59)

the oldest snapshot.

requires factory passwords. This diagnostic code

should be cleared only when you are certain that

The ECM stores the snapshots in memory. The

the personality module is for the specific engine.

memory is maintained through the unswitched

battery connections. If the unswitched + battery

5. Unlock a Customer Parameter That is Locked.

pins are disconnected, or if the vehicle batteries

are disconnected, the snapshot information is

If a Customer Parameter has been locked

maintained by the internal battery in the ECM .

out, Factory Passwords are required to unlock

the parameter. Also if a Customer Parameter

Also, the snapshots can be cleared manually by

has been locked out, Factory Passwords

using ET. Snapshots are automatically cleared by

are required to change the parameter. Refer

the ECM after 100 hours of operation. Snapshots

to Troubleshooting, "Customer Specified

are similar to diagnostic codes in this characteristic.

Parameters" for additional information.

NOTICE

i01443147

Operating the engine with a Personality Module not

Factory Passwords

designed for that engine will damage the engine. Be

sure the Personality Module is correct for your engine.

SMCS Code: 1901

Factory passwords are required to perform each of

Certain other codes require customer passwords.

the following six functions:

The majority of logged codes do not require

passwords to be cleared. Since the factory

1. Program a New ECM.

passwords contain alphabetic characters, the

Electronic Technician (ET) may perform these

When an ECM is replaced, the System

functions. In order to obtain the factory passwords,

Configuration Parameters must be programmed

proceed as if you already have the password. At

into the new ECM. A new ECM will allow these

some point, if the factory passwords are actually

parameters to be programmed once without

needed, the Electronic Technician (ET) will request

Factory Passwords. After the initial programming,

the factory passwords and the Electronic Technician

these parameters are protected by factory

(ET) will display the information that is required to

passwords.

obtain the passwords.

2. Rerate to Another Engine Family

Note: The "Customer Parameter Lockout" may

restrict changing some Customer Parameters

This requires changing the Personality Module

unless Factory Passwords are obtained. If changing

Code, which is protected by factory passwords.

a Customer Parameter indicates that the Factory

This includes changing from a non-multitorque

Passwords are required, the Parameter has been

personality module to a multitorque personality

Locked Out. Refer to Troubleshooting, "Customer

module.

Specified Parameters" for additional information.

3. Read Customer Passwords