DD15 Troubleshooting – Section 65.1 SPN 698/FMI 5

Section 65.1
SPN 698/FMI 5

This diagnosis is typically Grid Heater circuit failed open.‪

Check as follows:‪

1. Disconnect the Grid Heater harness connector.
2. Turn the ignition ON (key ON, engine OFF).
3. Measure the voltage between pin 2 of the Grid Heater harness connector and ground.

   Note: Voltage measurement must be taken with the first minute of key ON. If this was not done, cycle the key and recheck voltage.

   1. If the voltage is greater than 11 volts, go to step 6 .
   2. If the voltage is less than 11 volts, go to the next step.
4. Cycle the ignition switch.
5. Recheck the voltage between pin 2 of the Grid Heater harness connector and ground.
   1. If the voltage is greater than 11 volts, go to the next step.
   2. If voltage is still less than 11 volts, go to step 11 .
6. Measure the voltage between pin 3 of the Grid Heater harness connector and ground.
   1. If the voltage is greater than 11 volts, go to step 10 .
   2. If voltage is less than 11 volts, go to the next step.
7. Turn the Ignition OFF.
8. Disconnect the MCM 120–pin connector.
9. Measure the resistance between pin 3 of the Grid Heater harness connector and pin 92 of the MCM 120–pin connector.
   1. If the resistance is greater than 3 ohms, repair open between pin 3 of the Grid Heater harness connector and pin 92 of the MCM 120–pin connector. Refer to "65.1.1 Verify Repairs" .
   2. If the resistance is less than 3 ohms, go to the next step.
10. Measure the resistance between pin 1 of the Grid Heater harness connector and ground.
    1. If the resistance is greater than 3 Ω, replace the Grid Heater. Refer to "65.1.1 Verify Repairs" .
    2. If the resistance is less than 3 Ω, repair short to ground between pin 3 of the Grid Heater harness connector and pin 79 of the MCM 120–pin connector. Refer to "65.1.1 Verify Repairs" .
11. Measure the resistance between pin 2 of the Grid Heater harness connector and pin 41 of the MCM 120–pin connector.
    1. If the resistance is greater than 3 Ω, repair open between pin 2 of the Grid Heater harness connector and pin 41 of the MCM 120–pin connector. Refer to "65.1.1 Verify Repairs" .
    2. If the resistance is less than 3 Ω, replace the Grid Heater. Refer to "65.1.1 Verify Repairs" .

Section 65.1.1
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.

   ENGINE EXHAUST ‪
   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. If assistance is required, call the Detroit Diesel Customer Support Center at 313–592–5800.