Series 60 DDEC V Troubleshooting

Section 70.2 Troubleshooting Flash Code 74, PID 70/FMI 4

Section 70.2
Troubleshooting Flash Code 74, PID 70/FMI 4

The following procedure will troubleshoot Flash Code 74. For system overview, see Figure "Optimized Idle Schematic" . ‪

Section 70.2.1
Check Diagnostic Data Reader for Codes

Perform the following steps to check the diagnostic tool for codes:‪

  1. Turn the vehicle ignition switch ON.
  2. Plug in the diagnostic tool. Check for active and inactive Optimized Idle codes.

    Note: Service any other logged codes first.

  3. Visually examine the diagnostic tool for code 74.
    1. If code 74 was logged, check for short to ground. Refer to "70.2.2 Check for Short to Ground" .
    2. If code 74 was not logged, verify fault has been resolved. Refer to "70.2.3.1 Verify Repairs" .

Section 70.2.2
Check for Short to Ground

Perform the following steps to check for short to ground:‪

  1. Open the vehicle hood. Refer to OEM guidelines.
  2. Turn the vehicle ignition switch to the ON position and plug in the diagnostic tool.

    Note: The diagnostic tool may already be installed.

  3. Looking at the diagnostic tool, select switch/light status (Park Brake/ISD) and verify that it is On.
    1. If the Park Brake status is not ON, go to step 4 .
    2. If the Park Brake status is ON, the input wire is shorted to ground between the hood switch and the ECM/ECU. Repair or replace the wire. Verify fault has been resolved. Refer to "70.2.3.1 Verify Repairs" .
  4. Close the vehicle hood. Refer to OEM guidelines.
  5. Put the transmission in gear. Refer to OEM guidelines.
  6. Looking at the diagnostic tool, verify that the switch/light status (Park Brake) is ON.
    1. If the park brake status is not ON, continue checking for a short to ground. Go to step 7 .
    2. If the Park Brake status is ON, the input wire is shorted to ground between the hood switch and the neutral switch. Repair or replace the wire. Verify fault has been resolved. Refer to "70.2.3.1 Verify Repairs" .
  7. Put the transmission in neutral. Refer to OEM guidelines.
  8. Ensure the parking brake is not set. Refer to OEM guidelines.
  9. Looking at the diagnostic tool, verify that the switch/light status (Park Brake/ISD) is ON.
    1. If the Park Brake/ISD status is not ON, check for vehicle speed. Refer to "70.2.3 Check Vehicle Speed" .
    2. If the Park Brake/ISD status is ON, the input wire is shorted to ground between the park brake switch and the neutral switch. Repair or replace the wire. Refer to "56.2 Troubleshooting Flash Code 54, PID 84/FMI 12" . Verify fault has been resolved. Refer to "70.2.3.1 Verify Repairs" .

Section 70.2.3
Check Vehicle Speed

Perform the following steps to check vehicle speed: ‪

warning

PERSONAL INJURY

To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

  1. Start engine with vehicle in park. Refer to OEM guidelines.
  2. Plug the diagnostic tool.
  3. View ECM/ECU data list (vehicle speed in mile/h or km/h).
  4. Increase engine rpm.
  5. Verify vehicle speed.
    1. If vehicle speed did not vary, verify fault has been resolved. Refer to "70.2.3.1 Verify Repairs" .
    2. If vehicle speed did vary or was ever greater than 0 rpm, perform flash code 54 troubleshooting. Refer to "56.2 Troubleshooting Flash Code 54, PID 84/FMI 12" . Upon completion of repair, verify fault has been resolved. Refer to "70.2.3.1 Verify Repairs" .
Section 70.2.3.1
Verify Repairs

Perform the following steps to verify repairs for flash code 74. ‪

  1. Turn vehicle ignition to the OFF position.
  2. Reconnect all connectors.
  3. Close vehicle hood. Refer to OEM guidelines.
  4. Set the park brake. Refer to OEM guidelines.
  5. Put the transmission in neutral position. Refer to OEM guidelines.
    warning

    PERSONAL INJURY

    To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

  6. Start the engine.
  7. Turn the cruise master switch to the ON position.

    Note: If the switch was set to the ON position before the vehicle was started, turn the switch to the OFF position and then to the ON position.

  8. Wait for the engine to shut down.

    Note: After the idle timer expires, the engine will either shut down or continue to run to charge the battery or keep the oil temperature between 16°C (61°F) and 40°C (104°F).

  9. Turn the thermostat on (if installed).
  10. Adjust the set point and heating and cooling mode until the thermostat requires the engine to start.

    Note: If the thermostat is not installed, wait for the lube oil temperature to fall below 16°C (61°F).

    Note: The alarm will sound and the engine will start. Vehicle power (blower fans) will turn on approximately 30 seconds after the engine starts, due to the thermostat.

  11. Verify that Optimized Idle operates properly.
    1. If Optimized Idle is not operating properly, refer to "70.2.1 Check Diagnostic Data Reader for Codes" to troubleshoot code 74.
    2. If Optimized Idle is operating correctly, troubleshooting is complete.


Series 60 DDEC V Troubleshooting Guide - 6SE570
Generated on 10-13-2008

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