91.2
TROUBLESHOOTING VEHICLE HARNESS +5 VOLT SUPPLY
91.2 TROUBLESHOOTING VEHICLE HARNESS +5 VOLT SUPPLY
The following procedure will troubleshoot vehicle harness.
91.2.1
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 code 168/1 is logged, refer to section 46.3.1.
[b] If code 168/1 is not logged, refer to section 91.2.2.
91.2.2
Check for +5 Volts
Perform the following steps to check for +5 volts at the Throttle Position Sensor (TPS).
1. Turn vehicle ignition switch OFF.
2. Disconnect the TPS (disconnect the VSG and PGS, if applicable).
3. Turn vehicle ignition switch ON.
4. Measure voltage on the TPS and VSG harness connector, pin C (#916) (red lead) to pin A
(#952) (black lead), and pin A to pin B at the PGS connector, if applicable.
[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 91.2.5.
[b] If the voltage measurement is less than 4.7 volts, refer to section 91.2.3.
[c] If the voltage measurement is greater than 5.2 volts at all connectors,
refer to section 91.2.8.
91.2.3
Check for +5 volts or Return Open
Perform the following steps to check for +5 volts or return open.
1. Turn vehicle ignition switch OFF.
2. Disconnect the vehicle harness connector at the ECM.
3. Install a jumper wire between pins A and C of the TPS harness connector.
4. Measure resistance between sockets A3 and C3 of the vehicle harness connector.
[a] If the resistance measurement is less than or equal to 5 , refer to section 91.2.4.
[b] If the resistance measurement is greater than 5
or open, either the vehicle +5 volt
line (#916) or the sensor return line (#952) is open. Refer to section 91.2.9.
All information subject to change without notice.
91-4
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
