Mitsubishi Eclipse 1990 Service Manual page 433

Scan tool 62
Code General scan tool Upstream
No.
21
[Comment]
Background
Upstream heated oxygen sensor requires a heater circuit for proper operation.
The heater circuit is supplied with battery voltage through the
A failure in the sensors heater circuit prevents it from providing accurate data to the PCM.
the PCM monitors more than 1.2 volts, the sensor has shorted to heater circuit voltage.
Range of Check
Two or more minutes after the engine starts
Engine coolant temperature:
Set Condition
Heated oxygen sensor output voltage is more than 1.2
Check trouble symptom.
Check the harness wire between the PCM and the heated oxygen
sensor (front).
Replace the PCM.
Scan tool 68
Code General scan tool PCM Failure
No.
53
[Comment]
Set Condition
There is no communication between
the PCM.
[Comment]
Background
Battery temperature input is used to adjust the generator charging rate based upon the
ambient temperature around the battery.
Range of Check
switch: ON
Set Condition
The sensor voltage is not within the acceptable range of 0.3 to 4.9 volts for 3 seconds
or more.
Replace the PCM.
ENGINE (NON-TURBO)>
or more
for 3 seconds.
OK
OK
NG
OK
Communications
in the control module.
TSB Revision
Shorted to Volt;
relay relay):
NG
Replace
NG
Repair
NG
Repair
Probable cause
PCM failed
Probable cause
Battery temperature sensor failed
PCM failed
Heated oxygen sensor failed
W i r i n g
,
PCM