MBE 4000 DDEC VI Troubleshooting – Section 54.2 SPN 636/FMI 3

Section 54.2
SPN 636/FMI 3

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

Section 54.2.1
Open Circuit Check

Check as follows:‪

1. Disconnect the MCM 120–pin connector.
2. Measure the resistance between pins 43 and 73 of the MCM 120–pin connector.
   1. If the resistance is greater than 1400 Ω, go to step 5 .
   2. If the resistance is less than 1400 Ω, go to step 3 .
3. Disconnect the CKP Sensor.
4. Measure the resistance pins 43 and 73 of the MCM 120–pin connector.
   1. If the resistance is greater than 3 Ω, replace the CKP Sensor. Refer to "55.2.2.1 Verify Repairs" .
   2. If the resistance is less than 3 Ω, repair the short between pins 42 and 43 of the 120–pin MCM connector and the CKP Sensor. Refer to "55.2.2.1 Verify Repairs" .
5. Disconnect the CKP Sensor.
6. Jumper pins 1 and 2 of the CKP Sensor harness. See Figure "Crankshaft Position Sensor Wiring" .
   

   Figure 1. Crankshaft Position Sensor Wiring

7. Measure the resistance between pins 43 and 73 of the MCM 120–pin connector.
   1. If the resistance is greater than 3 Ω, repair the open between pins 43 and 73 of the MCM 120–pin connector and the CKP Sensor. Refer to "55.2.2.1 Verify Repairs" .
   2. If the resistance is less than 3 Ω, replace the CKP Sensor.Refer to "55.2.2.1 Verify Repairs" .

Section 54.2.1.1
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.
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.