Cat Lift Trucks (& Caterpillar) EP18KT:
code 18

The temperature lamp show on.
At last very slowly walks and now writes
code 18
  • Posted 13 Sep 2018 22:17
  • Discussion started by dato_georgia
  • Georgia
Showing items 1 - 7 of 7 results.
I have had broken wire at the terminal multiple times. Raise and CHAIN the mast. Visually inspect the wiring.Test circuit with meter and schematic at back also.
  • Posted 5 Oct 2018 09:43
  • Reply by Service_T
  • Kansas, United States
I'm wondering how i can convince
that the logical fee is corrupted.

there is no error code, only the temperature on, and walking slowly about 5 km dials.
the climb completely stops.
if a temperature sensor pictogram is lit it should have a symbol indicating hydraulic or drive, the icon should look like a drive gear or for hydraulic it will have a drop like fluid in it. Which ever one is lit you should check that temp circuit. check on the motor itself for a temperature sensor, if no temp sensor is mounted on the motor itself then the problem is indicating that the motor controller for that system is getting hot. also double check the sensor wiring going into the motors, there are 4 wires, 2 are for temp sensing and the other 2 are for brush wear indicators, if all that checks ok then check the motor controller's temperature using a diagnostic temp gun and see how hot it is really getting. If the controller is at normal temp then you still have issues in the circuitry, possibly in the logic card.
  • Posted 21 Sep 2018 00:13
  • Modified 21 Sep 2018 00:16 by poster
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
The codes disappeared.
works But it goes very slowly.
and displey shows the temperature indicator.
hello dato_georgia
well trying to repair the h-bridge did change symptoms and error codes but the code 17 is Right Motor, faulty field circuit, and code 19 is Right Motor, Field Over-current.

As a general practice is is best to replace the h-bridge board and not repair is as you cannot possibly know every component on it that may be bad, also the IGBT Motor transistor should also be replaced at the same time because the h-bridge can actually cause damage to the drive transistor. (at least the manual suggests changing them both when the h-bridge board is being replaced.

As long as you have verified that the right drive motor and sensor circuits are in fact OK and none of the cables or sensor wires are shorted or damaged and the motor itself is not shorted in ANY way then the h-bridge board and/or drive transistor are usually the issue.
And lastly the logic card can get damaged as well but from my experience this is rare but it can happen.
  • Posted 19 Sep 2018 10:30
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
in card H bridge I replaced 1 moft. transistor and 2 stabilitrone and now code 17 and 19
code 18

possible causes
faulty right motor field circuit, faulty H bridge board, faulty logic card, faulty controller harness

how the code is triggered
when h bridge board detects over-current for right FET (transistor)
software checks following signal and detects fault when the signal is under 1V.
-R. Field Error (CN2-13)
Areas to check
disconnect battery plug, check right motor field cable terminals, logic card CN2-13 terminal and H bridge board CN2-16 terminal for abnormality.
If acceptable
-check continuity between following terminals. Right motor field cables
-logic card CN2-13 and CN2-63(neg)
If unacceptable
correct or replace cables.

If not shorted turn on key and confirm 18 is displayed.
Confirm voltage between CN2-13 and CN2-63(neg) with multimeter. If shorted correct or replace faulty circuit.

If 0v replace H-bridge board, If about 15v replace logic card.
  • Posted 17 Sep 2018 22:32
  • Reply by swoop223
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com

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