Hummer H1 Service Manual page 1108

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DTC P0182 Fuel Temperature Sensor Circuit
Low Voltage
C5
C27-D14
5 VOLT
REFERENCE
Circuit Description
The fuel temperature sensor is a thermistor that controls signal
voltage to the PCM. When the fuel is cold, the sensor resis-
tance is high, therefore the PCM will see high signal voltage.
As fuel warms, sensor resistance becomes less and voltage
drops. The fuel temperature sensor is integrated with the opti-
cal sensor. This is a type B DTC.
Conditions for Setting the DTC
• Fuel temperature greater than 102°C (215°F).
• Conditions met for 2 seconds.
Action Taken When the DTC Sets
Poor idle quality during hot conditions.
Conditions for Clearing the MIL/DTC
• The PCM will turn the MIL off after three consecutive
trips without a fault condition.
• A History DTC will clear when forty consecutive
warm-up cycles that the diagnostic does not fail (coolant
temperature has risen 5°C (40°F) from start up coolant
temperature and engine coolant temperature exceeds
71°C (160°F) that same ignition cycle).
• Use of a Scan Tool.
05745159
A E
5 VOLT
REFERENCE
PUMP CAM HIGH
SENSOR RESOLUTION SENSOR
GROUND
SIGNAL SIGNAL
B C D F
C3 B8 C1
C29-A4 C29-A2 C27-D9
CAM HIGH SENSOR
SENSOR RES GROUND
SIGNAL SIGNAL
PCM/Tech 1 Scan Tool 39
STEPPEN MOTOR (ITS)
OPTICAL/ FUEL
TEMP SENSOR
D A
C12 C2 A3
C27-C8 A7 A8
C29
FUEL TEMP ITS ITS
SIGNAL HI LO
Diagnostic Aids
A scan tool reads fuel temperature in degrees centigrade. After
engine is started, the fuel temperature should rise steadily.
Test Description
Number(s) below refer to the number(s) on the diagnostic table.
1. This step determines if DTC P0182 is a hard failure or an in-
termittent condition.
3. This step will determine if signal circuit is shorted to
ground.
INJECTION TIMING
M
B C
A2 A6 A7
A9 A10
ITS ITS
Powertrain
LO HI
Control
POWERTRAIN
Module
CONTROL
(PCM)
MODULE
9-S12-070
3-1-01