MALFUNCTION OF MAIN RELAY
(DTC CODE P0686 / DIAGNOSIS MONITOR CODE 51)

If "engine system failure" is indicated:

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Symptom of malfunction
  • Cruise functions are disabled.
  • Idle stop functions are disabled.
  • DPR regeneration is disabled.
  • PTO functions are disabled.
Output limit, etc. Output limit
Malfunction indicator light Light out
Multi information Engine system failure
Possible cause of malfunction Malfunction of main relay

If "post-driving engine inspection" is indicated:

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Symptom of malfunction

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Output limit, etc. Without
Malfunction indicator light Light out
Multi information Post-driving engine inspection
Possible cause of malfunction Malfunction of main relay

If "preheater failure" is indicated:

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Symptom of malfunction

Startability may be poor during cooling.
Output limit, etc. Without
Malfunction indicator light Light out
Multi information Preheater failure
Possible cause of malfunction Malfunction of main relay

 

1. Measuring voltage between terminals

Detail

2. Measuring voltage between terminals

Detail

DTC Clear

Detail