DD15 SPN 636/FMI 1 Troubleshooting

SPN 636/FMI 1

The diagnostic condition is typically CKP Sensor Signal Voltage Too Low.‪

Note: If the sensor is removed, be sure to check the sensor tip for metal debris and clutch material and clean it if necessary.

Check as follows:‪

  1. If fault occurs only when cranking the engine (and engine will not start), check that the CKP and Camshaft Position (CMP) sensors are correctly wired to the MCM.
    1. If wires are not correctly wired, repair or replace wires as required. Refer to “56.1.1 Verify Repairs” .
    2. If wires are correctly wired, go to the next step.
  2. If fault occurs at other times then when cranking the engine, check that the CKP Sensor position is correct (the sensor is seated in all the way and the tip of the sensor is clean).
    1. If fault is not active after checking CKP Sensor position, repair the CKP Sensor clamping sleeve. Refer to “56.1.1 Verify Repairs” .
    2. If fault is still active after checking the CKP Sensor position, go to the next step.
  3. Check the flywheel position through the inspection window of the timing case using turning tool. Look for timing marks and damage.
    1. If the flywheel is out of position, repair or replace, as required. Refer to “56.1.1 Verify Repairs” .
    2. If the flywheel is not out of position, go to the next step.
  4. Check crankshaft axial play.
    1. If axial play is not within specifications, repair or replace crankshaft thrust bearings, as required. Refer to “56.1.1 Verify Repairs” .
    2. If axial play is within specifications, replace the MCM. Refer to “56.1.1 Verify Repairs” .

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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