CONFIDENTIAL TIBU3788-01

There have been dealer reports of engine ECMs locking up when new software is being installed. Dealer staff may see a message on the service tool such as: "The ECM is not responding to the service tool. Error code 864256". The flashing will typically hang up after 88% complete. When you reconnect, ET will not be able to communicate. Messages you typically get: "The communication adapter was unable to connect to the ATA data link. Error # 441. The requested protocol is not compatible with an existing datalink." You may also see: "The software file and the ECM are not compatible. Process aborted ? Error Code: 147456."

The two new software part numbers are:

222-XXXX (needed when a 172-0802 ECM is replaced by a 156-7156 ECM)

214-YYYY (needed when new-style injectors are installed)

If you are considering performing Product Support Program PS50424 on one of the above-listed machines, you may want to delay the program until new software is released. New software will be released in the near future to resolve this issue. Once the flashfiles are in SIS Web, a follow-up TIB will announce the new software?s availability.

On machine engines that have an older ECM that fails (145-7808 or 172-0802), the current 156-7172 production ECM will be needed for parts service. This will require using one of the 222-XXXX flashfiles. To minimize the possibility of locking-up the ECM, the dealer service staff can do one of the following:

• Flash the ECM before traveling to the job site. This will require a By-Pass harness.
• Flash the ECM on the engine. A By-Pass harness is recommended. If a By-Pass harness is used, disconnect the machine wiring harness before flashing the engine ECM. Dealers report that this method reduces the number of lock-ups.

If the dealer does not have a By-Pass harness, one will have to be purchased or assembled. If a new 129-2018 Wiring Harness Assembly (By-Pass) is purchased, modifications are necessary. Instructions on how to modify a By-Pass harness (Method 1: Modify a By-Pass Harness) and assemble a By-Pass harness (Method 2: Assemble a By-Pass Harness) appear later in this TIB.

Note: When flashing engine ECMs, always download the file from SIS Web to the computer?s hard drive. The service person should then upload (flash) to the ECM from the computer?s hard drive. For a listing of all models affected and the current software, refer to REHS1385-02, "Introduction of New 3408E and 3412E Hydraulic Electronic Unit Injectors".

When flashing an on-engine ECM with the current files, Caterpillar recommends the use of a By-Pass Wiring Harness Assembly. Using a By-Pass Wiring Harness Assembly to flash an on-engine ECM allows the machine wiring harness to be disconnected from the ECM. When the machine wiring harness is disconnected from the ECM, a source of noise is eliminated from the ECM. This noise, if not eliminated, can contribute to the "locking up" which is experienced periodically when flashing an ECM.

To flash an off-engine ECM (at the shop), a By-Pass Wiring Harness Assembly will need to be used. Perform the following procedure.

Modifying the 129-2018 Wiring Harness (By-Pass)

Three additional wires (16 gauge) will have to be added.

1. Use a 16-gauge wire to connect Pin 3 (40-pin connector) to Pin E (9-pin connector).
2. Use a 16-gauge wire to connect Pin 9 (40-pin connector) to Pin D (9-pin connector).
3. Use a 16 gauge wire to connect Pin 23 (40-pin connector) to Pin A (2-pin connector). The 2-pin connector is on the same end of the wiring harness as the 9-pin connector. Pin A of the 2-pin is Power. Pin B of the 2-pin connector is Ground.

Step 3 will power-up the ECM and allow the ECM to be flashed on the bench (off the engine). The 129-2018 Wiring Harness Assembly has battery and ground clips attached to the power source (red and black boots).

Use the following diagram to assemble a By-Pass Harness.

Illustration 1. By-Pass Harness Wiring Diagram.

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