Reading Diagnostic Trouble Codes

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Reading Diagnostic Trouble Codes

The “Service Engine Soon” light located on the dash notifies the operator of a problem. Whenever the light comes on, the Engine Control Unit (ECU) will store the location of the malfunction in its memory as a trouble code. The light can be used to display trouble codes that have been stored due to system malfunctions.

When the light is in proper working order, it will illuminate when the key is in the ON position and the engine is not running. If the light does not illuminate with key on/engine off, repair it immediately. Once the engine is in run mode, the light should go off. If the light is illuminated while the engine is in the run mode, the ECU has stored a trouble code.

System trouble codes can be detected and displayed by using the “Service Engine Soon” light. Locate the diagnostic connector in the wiring harness under the dash near the operator's left knee. Remove the dust cover.

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Outer Terminals

A - Outer Terminals

1. Use a piece of wire to connect the outer terminals (A) in the diagnostic connector.

2. Turn key to ON position, but DO NOT start engine.

3. 
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   Check Engine Light Trouble Code

   The “Service Engine Soon” light will begin to flash a code number. For example, flash once...short pause...flash twice...long pause. This example is code 12.

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4. The ECU will flash each trouble code that is in memory three times in numerical order. Code 12 will always be flashed first. This code means that the self-diagnostic system is working correctly. If this is the only code flashed, all systems are working correctly.

5. If other trouble codes are flashed, refer to the charts on the next pages.