Turbocharger Speed Sensor Faults; Vpod; Relative Humidity/Turbo Compressor Inlet Temperature Sensor; Turbo Compressor Outlet Temperature - Detroit Diesel Series 60 EGR Technician Manual

SERIES 60 EGR TECHNICIAN'S MANUAL

Turbocharger Speed Sensor Faults

Turbocharger speeds rarely exceed 100,000 rpm for any length of time. Speeds exceeding
100krpm and dropping rapidly is a warning sign. 30krpm changes in speed at 1 second intervals
is almost impossible. Consider a false signal being sent to the ECM rather than this event actually
occurring. The ECM is responding to the signals it is receiving from sensors.
Monitor the turbocharger speed and the engine boost, watch for normal, expected changes. Note
in one of the next snap shot samples that the turbocharger speed reaches 108,000 rpm and boost is
only 7.1psi. Turbo Speed Sensors (pn 23530252) that have a date code stamped on the sensor
connector between 0703 to 3703 should be changed first if suspect then contact DDC Customer
Support Center at 313-592-5800 for further assistance.
NOTE:
Remember that if a sensor fails and sends a signal to the ECM that is within a normal
threshold for that sensor. No code will be generated however DDEC could try to respond
to the false signal.

VPOD

The Variable Pressure Orfice (or Output) Device is used to control the pressure to the actuators
used for the EGR valve and turbocharger vane position. The most common failure is external
leakage of air. You can hear the leak when you activate the PWM for each VPOD.

Relative Humidity/Turbo Compressor Inlet Temperature Sensor

This sensor is a DDC part installed and wired by the OEM. Most faults here have been due to
incorrectly wired 10 pin connector. The ECM will usually log a fault code for one or the other
side this combination sensor.

Turbo Compressor Outlet Temperature

During heavy loaded operation the outlet of the turbo to the charge air cooler becomes very hot.
Logic built into DDEC allows for derating of torque to reduce these temperatures to prevent
charge air cooler failures. The derate code (flash code 49) of 404 14 logs without turning on the
check engine light. This inactive code is stored to allow technicians the ability to assure the driver
there is not any fault of failure and this operation is normal to the EGR system.
7-3
All information subject to change without notice. (Rev. June 2005)
7SE60 0506 Copyright © 2005 DETROIT DIESEL CORPORATION