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Machine Misbehavior: Part 2, Propulsion Solution

June 7, 2018 8:30 AM by Tennant Company



And the answer is....


No matter how well-maintained a machine is, unusual service problems can crop up. In this two-part post, we present a perplexing service issue and explore the response.

In Part 1, we looked at a T12 with a propulsion problem. The Machine User Interface Panel showed all systems normal, but when the Propel Switch was engaged and the Propel Pedal depressed, the machine would move about 10 feet, very slowly, and then stop. We offered four options to help diagnose the problem:

  1. Check the circuit breakers and confirm that none are tripped
  2. Using the on-board propel diagnostic, look for anything that is abnormal
  3. Observe the Curtis-Wright 1232 Controller LED status indicators to see if any faults are being reported.
  4. Both B and C

If you chose option D as the best diagnostic approach, you’re right! Looking at the on-board propel diagnostics will likely show that this T12 is reporting a very high drive motor temperature. Looking at the Curtis-Wright 1232 Controller LED status indicators will back this up. The controller will probably report a code #29, which shows this in the service manual:


Diagnostic code chart shows service code #29 details

This confirms that the problem is the electrical connection between the motor thermistor and the controller. Fix that connection and the T12 will be up and running!


Did you miss part 1 of this post?



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