Detroit Diesel MBE 4000 DDEC VI Troubleshooting Manual page 324

32.1 SPN 174/FMI 3
[a] If the voltage is between 2.75 and 3.25 volts, repair the open circuit between
pin 1 of the SFT Sensor harness connector and pin 55 of the 120–pin MCM
connector.See Figure 32-2. Refer to section 32.1.1.1.
[b] If the voltage is less than 2.75 volts, repair the open circuit between pin 2 of the SFT
Sensor harness connector and pin 77 of the 120–pin MCM connector. See Figure
32-2. Refer to section 32.1.1.1.
Figure 32-2 MCM 120–pin Connector
7. Disconnect the 120–pin MCM connector and measure the resistance between pins 1
and 2 of the SFT Sensor harness connector.
[a] If the resistance is less than 5 Ω, repair the short between pins 55 and 77 of the
120–pin MCM connector. Refer to section 32.1.1.1.
[b] If the resistance is greater than 5 Ω, replace the sensor. Refer to section 32.1.1.1.
32.1.1.1 Verify Repairs
Perform the following steps to verify repairs.
1. Turn the ignition OFF and reconnect all connectors.
2. Turn ignition ON. Clear codes.
3. Start and run the engine for eight minutes. Stop engine.
4. Check diagnostic tool for codes.
[a] If no codes are logged, no further troubleshooting is required.
32-4
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(Rev. ) All information subject to change without notice.