
90 RENR9348-01
Troubleshooting Section
Diagnostic Fun
ctional
Tests
i02410077
5 Volt En gine Pressure Se nsor
SupplyCircuit-Test
SMCS Code: 1439-038
System Opera
tion Description:
Use this procedure to troubleshoot any suspect
problems wit
h the +5 V sensor supply.
Use this procedure to troubleshoot the system when
one of the fol
lowing diagnostic codes is active or
easily repeated:
•
262-03 5 Volt
Sensor DC Power Supply short to
+batt
•
262-04 5 Vol
t Sensor DC Power Supply short to
ground
The Electro
nic Control Module (ECM) supplies a
regulated voltage of 5.0 ± 0.2 VDC to the following
sensors:
•
Atmospheric pressure sensor
•
Boost press
ure sensor
•
Engine oil pressure sensor
•
Fuel pressure sensor
The supply f
or the +5 V engine pressure sensor is
routed from the ECM to terminal A of each pressure
sensor connector. The sensor return from the
ECM connec
tor goes to terminal B of each sensor
connector. The 5 V sensor supply is output short
circuit protected. A short circuit to the battery will not
damage the
circuit inside the ECM.
Note: The sensors are not protected from
overvolta
ge. A short from the supply line to the
+Battery may damage the sensors. If the CID-FMI
262-03 is logged, it is possible that all of the sensors
have been
damaged. Repair the 5 V sensor supply
and check for any active diagnostic codes for the
sensor in order to determine if a sensor has failed.
A +5 V diagnostic code is probably caused by a
short circuit to ground or a short circuit to another
voltage
source in the harness. The next likely cause
isaproblemwithasensor.Theleastlikelycauseis
a problem with the ECM.