SWL model 924G, 924Gz, 928Gz and IT28G ECM problems. Caterpillar

CONFIDENTIAL TIBU4373-01

This TIB is intended to assist the dealer technician in identifying possible problems related to ECMs and to prevent unnecessary replacement of related parts.

There are reported failures involving the 230-7490 Transmission ECM, and the 190-0416 Engine ECM on certain SWL. Under certain conditions any one of the ECMs could momentarily enter into a reset condition during normal operations.

During a transmission ECM reset, the instrument cluster would reset, causing a lamp test, gauge test and action alarm test. The gauge cluster reset will appear the same as a normal power reset using the keyswitch.

If the transmission ECM goes into a reset condition while driving in either forward or reverse, the transmission will turn off all solenoids, forcing the transmission into neutral. The engine will continue to run. The gauge cluster needles will sweep to the right, the diagnostic lamps will flash and the action alarm will sound. To continue operation, move the shift lever to neutral and back to forward or reverse. This will restore drive to the machine. The backup alarm may skip a beat if the machine is in reverse.

There will be NO loss of steering or brake functions if the Transmission ECM goes into a reset condition.

During a transmission ECM reset, the hydraulic implements may momentarily pause. The operator will not be able to change bucket or lift arm position. After reset, bucket and lift arm control will return to normal operation.

Ride control will drop out while the transmission ECM is in reset, but will return after the ECM recovers.

Cooling fan for hydraulics and engine will momentarily go to full speed.

Reversing fan keeps debris from clogging the cooling system. The fans may make a noise, if the reset occurs.

Service brake neutralizer forces transmission into neutral when service brake is activated. If reset occurs while this happens, transmission will shift into neutral.

Engine ECM will record a fault that communication was lost with the transmission ECM, but the engine will continue to run.

Machine security system, if installed, may delay reset recovery by about 1 sec.

If the engine ECM goes into a reset condition during normal operation, the engine will shut down. In order to restart the machine, the operator will be required to go through the normal start-up procedure.

The engine ECM is expecting communications with the transmission ECM to sustain throttle lock. If throttle lock is engaged and the transmission ECM resets, throttle lock will drop out, returning engine to throttle pedal control. If the engine ECM resets, throttle lock will have to be set when the engine is restarted.

If the transmission ECM resets while speed limit is engaged; engine speed will go to desired engine speed. If the engine ECM resets, the speed limit feature will start working when the engine is restarted.

There will be NO loss of steering or brake functions if the Engine ECM goes into a reset condition.

If the engine ECM resets with Machine Security System in installed, the engine will require a key cycle to restart the Engine. The key cycle will reset the MSS ECM.

Table 1

All ECMs manufactured after September 7, 2004 have had the reset problem rectified, and have been 100% tested before being installed into production machines (see detailed date codes in Table 1).

All ECMs that have a date code later than September 7, 2004 are good ECMs and will not be affected by the reset issue.

Refer to the associated machine-troubleshooting guide if a situation arises on a machine with the latest ECM installed.

All suspected ECMs have been purged from worldwide parts stock.

We do not intend to release a field rework program, but will continue to monitor the situation and will revise if needed.

Any defective components should be replaced under normal warranty.

If any of the problems detailed above occur on the machine, carry out the following diagnostic checks along with those in the service manual before replacing an ECM.

• Verify the battery connections to the gauge cluster are secure. Check the connector for tightness.
• Verify the data link connections to the gauge cluster are secure.
• Verify that all related connections for the function are correct and secure. Verify that the wires and pins are free from corrosion, abrasion and incorrect attachment.

If all connections are OK and the machine has experienced one or more failures in this list. Replace the ECM.

The date code is in the DDMMYY format.

Example: The date code for September 8, 2004 is (08-Sept-04) NONDNR. The date code for the ECM can be found on the top of the ECM. See example in Illustration 1.

Table 2

Illustration 1

ECMs made after September 7, 2004 have all been tested and will not be required to be changed out. If a machine generates any of these symptoms, refer to the associated machine-troubleshooting guide.

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