Spn 641/Fmi 31 - Detroit Diesel EPA07 Series 60 DDEC VI Troubleshooting Manual

57.6

SPN 641/FMI 31

57.6 SPN 641/FMI 31
This code typically means a turbo actuator internal error code, problem unknown.
57.6.1 Actuator Check
Check as follows:
1. Check for multiple codes.
[a] If 641/9, 641/11, 641/14 or 2795/9 are present, service those faults first.
[b] If only 641/31 is present, go to the next step.
2. Disconnect the turbo actuator.
3. Turn the ignition ON (key ON, engine OFF).
4. Measure the voltage between pins 1 and 2 of the turbo actuator connector on the engine
harness side.
[a] If the voltage is less than 11.5 volts, go to the next step.
[b] If the voltage is greater than 11.5 volts, go to step 6.
5. Measure the voltage between pin 1 of the turbo actuator harness connector and ground.
[a] If the voltage is less than 11.5 volts, repair the cause of low voltage between pin 1
of the turbo actuator harness connector and pin 93 of the MCM 120–pin connector.
Refer to section 57.6.1.1.
[b] If the voltage is greater than 11.5 volts, repair the open between pin 2 of the turbo
actuator connector on the engine harness side and pin 38 of the MCM 120–pin
connector. Refer to section 57.6.1.1.
6. Turn ignition OFF.
7. Disconnect the MCM 120–pin connector.
8. Measure the resistance between pin 3 of the turbo actuator harness connector and pin 74
of the MCM 120–pin connector.
[a] If the resistance is less than 3 Ω, go to the next step.
[b] If the resistance is greater than 3 Ω, repair the harness between pin 3 of the
turbo actuator harness connector and pin 74 of the MCM 120–pin connector.
Refer to section 57.6.1.1.
9. Measure the resistance between pin 4 of the turbo actuator harness connector and pin 75
of the MCM 120–pin connector.
[a] If the resistance is less than 3 Ω, replace the turbo actuator.
[b] If the resistance is greater than 3 Ω, repair the harness between pin 4 of the
turbo actuator harness connector and pin 75 of the MCM 120–pin connector.
Refer to section 57.6.1.1.
57-12
All information subject to change without notice.
Copyright © 2007 DETROIT DIESEL CORPORATION