DD15 SPN 636/FMI 3 Troubleshooting

SPN 636/FMI 3

The diagnostic condition is typically CKP Sensor has an open circuit.‪

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. Disconnect the CKP Sensor.
2. Measure the resistance across pins 1 and 2 of the CKP Sensor.
   1. If the resistance is greater than 140 Ω, replace CKP Sensor. refer to “56.3.1 Verify Repairs” .
   2. If the resistance is less than 140 Ω, go to the next step.
3. Disconnect the 120–pin MCM connector.
4. Measure the resistance across pins 1 and 2 of the CKP Sensor harness connector.
   1. If the resistance is greater than 5 Ω, go to the next step.
   2. If the resistance is less than 5 Ω, repair the short between pins 1 and 2 of the CKP Sensor harness connector and pins 42 and 43 of the 120–pin MCM connector. refer to “56.3.1 Verify Repairs” .
5. Measure the resistance between pin 1 of the CKP Sensor harness connector and pin 42 of the 120–pin MCM connector.
   1. If the resistance is greater than 5 Ω, repair the open between pin 1 of the CKP Sensor harness connector and pin 42 of the 120–pin MCM connector. refer to “56.3.1 Verify Repairs” .
   2. If the resistance is less than 5 Ω, go to the next step.
6. Measure the resistance between pin 2 of the CKP Sensor harness connector and pin 43 of the 120–pin MCM connector.
   1. If the resistance is greater than 5 Ω, repair the open between pin 2 of the CKP Sensor harness connector and pin 43 of the 120–pin MCM connector. refer to “56.3.1 Verify Repairs” .
   2. If the resistance is less than 5 Ω, go to the next step.
7. Bar the engine until the CKP Sensor is over a CKP tooth of the pulse wheel and check to be sure the tip of the sensor is clean.
8. Check the gap between the CKP Sensor and the tooth of the pulse wheel (0.020 to 0.040 in.). A depth micrometer can be used.
   1. If the gap setting is correct, repeat steps 1 and 2 . If the results are the same, call the Detroit Diesel Customer Support Center (313–592–5800).
   2. If the gap setting is not correct, adjust the CKP Sensor until the gap setting is correct and refer to “56.3.1 Verify Repairs” . If the problem returns, the pulse wheel may be loose or bad or damaged.

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.