Section 56.2
SPN 636/FMI 3

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

Section 56.2.1
Open Circuit Check

Check as follows:‪

1. Disconnect the CKP Sensor.
2. Measure the resistance across pins 1 and 2 of the CKP Sensor. See Figure "Crankshaft Position Sensor Wiring" .
   1. If the resistance is greater than 140 Ω, replace CKP Sensor. Refer to "56.2.2.1 Verify Repairs" .
   2. If the resistance is less than 140 Ω, go to step 3 .
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 step 5 .
   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. See Figure "Crankshaft Position Sensor Wiring" . Refer to "56.2.2.1 Verify Repairs" .
   

   Figure 1. Crankshaft Position Sensor Wiring

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 "56.2.2.1 Verify Repairs" .
   2. If the resistance is less than 5 Ω, go to step 6 .
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 "56.2.2.1 Verify Repairs" .
   2. If the resistance is less than 5 Ω, refer to "56.2.2 Crankshaft Position Sensor Gap Check" .

Section 56.2.2
Crankshaft Position Sensor Gap Check

Check as follows:‪

1. Bar the engine until the CKP Sensor is over a CKP tooth of the pulse wheel.
2. 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 "56.2.2.1 Verify Repairs" . If the problem returns, the pulse wheel may be loose or bad or damaged.

Section 56.2.2.1
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.
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.