Mercury D4.2L D-Tronic

EDI DIAGNOSIS SERVICE MANUAL NUMBER 22
Page 5E-24 90-860074--1 FEBRUARY 2002
Fuel Temperature Sensor
Scan Code: P0180
Blink Code: 3333
Malfunction Indicator Lamp: OFF
ECM
33
BLU/RED
BRN/PUR
63
75565
75409
a
b
c
d
1
2
3
4
7
6
5
a-Fuel Temperature Sensor (Inside Fuel Injection Pump)
b-5 Volt Reference Signal
c-Fuel Temperature Sensor Signal
d-Sensor Ground
CIRCUIT DESCRIPTION:
The Fuel Temperature Sensor is a thermistor (a resistor which changes value based on
temperature). Low temperature produces a high resistance, while high temperature causes
a low resistance.
The ECM supplies a 5 volt signal to the sensor through a resistor in the ECM and measures
the voltage. The ECM voltage will be high when the fuel temperature is cold, and low when
the fuel temperature is hot.
A failure in the Fuel Temperature Sensor circuit should set a Scan Code P0180.
CKT PIN
NAME
33 Sensor Ground (Analog –)
63 Fuel Temperature Sensor Signal