90.2
TROUBLESHOOTING ENGINE SENSOR HARNESS
90.2 TROUBLESHOOTING ENGINE SENSOR HARNESS
The following procedure will troubleshoot the engine sensor harness.
90.2.1
Check for Low Battery Voltage
Perform the following steps to check for low battery voltage.
1. Plug in the diagnostic data reader (DDR).
[a] If Flash Code 168/1 is logged, refer to section 46.3.
[b] If code 168/1 is not logged, refer to section 90.2.2.
90.2.2
Check for +5 Volts
Perform the following steps to check for +5 volts.
1. Turn vehicle ignition switch OFF.
2. Disconnect the Oil Pressure Sensor (OPS) and Turbo Boost Sensor (TBS) connectors.
3. If applicable, disconnect the Fuel Pressure Sensor (FPS).
4. Turn vehicle ignition switch ON.
5. At each sensor harness connector, measure voltage between socket C (red lead) and
socket A (black lead).
[a] If the voltage measurement is between 4.7 and 5.2 volts, the voltage reading is
correct. Check voltage at the next connector. If all connector voltage readings are
correct, refer to section 90.2.3.
[b] If the voltage measurement is less than 4.7 volts at any or all connectors,
refer to section 90.2.4.
[c] If the voltage measurement is greater than 5.2 volts at all connectors,
refer to section 90.2.6.
90.2.3
Check ECM Connectors
Perform the following steps to check the ECM connectors.
1. Check terminals at the ECM engine harness connector (both the ECM and harness side)
for damaged, bent, corroded and unseated pins or sockets.
[a] If the terminals and connectors are not damaged, check all sensors, especially OPS,
TBS, and TPS (on vehicle system), this indicates that there is no problem on the
engine sensor harness. Refer to section 91.1.
[b] If the terminals and connectors are damaged, repair them. Refer to section 90.2.7.
All information subject to change without notice.
90-4
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
