DD15 SPN 729/FMI 0 Troubleshooting

SPN 729/FMI 0

This fault condition is typically Grid Heater permanently on.‪

Check as follows:‪

  1. Disconnect the Grid Heater harness connector.
  2. Disconnect the MCM 120–pin connector.
  3. Measure the resistance between pin 1 of the Grid Heater harness connector and ground
    1. If the resistance is less than 5 Ω, repair short to ground between pin 1 of the Grid Heater harness connector and pin 79 of the MCM 120–pin connector. Refer to “74.1.1 Verify Repairs” .
    2. If the resistance is greater than 5 Ω, replace the Grid Heater. Refer to “74.1.1 Verify Repairs” .

Section 74.1.1
Verify Repairs

Verify repairs as follows:‪

  1. Turn ignition OFF.
  2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
  3. Clear codes with DDDL 7.0 or latest version.
    To avoid injury from inhaling engine exhaust, always operate the engine in a well-ventilated area. Engine exhaust is toxic.‪
  4. Start and bring engine up to operating temperature (over 140°F/60°C).
  5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes.

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