Pontiac Fiero 1988 Service Manual page 620

DRIVEABILITY A N D EMISSIONS - FUEL INJECTION (PORT) 6E3 A-37
MANIFOLD AIR TEMPERATURE
(MAT) SENSOR CIRCUIT
( L O W T E M P E R A T U R E INDICATED)
2.8L "P" SERIES (PORT)
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• DOES " S C A N " TOOL DISPLAY MAT -30°C OR COLDER?
YES NO
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DISCONNECT SENSOR.
JUMPER HARNESS TERMINALS TOGETHER.
" S C A N " SHOULD DISPLAY TEMPERATURE OVER 130°C .
DOES IT?
Y E S
FAULTY CONNECTION OR SENSOR.
DIAGNOSTIC AID
MAT SENSOR
TEMPERATURE TO RESISTANCE VALUES
(APPROXIMATE]
°F
°C
OHMS
210 100 185
160 70 450
100 38 1,800
70 20 3,400
40 4
7,500
20
-7
13,500
0 -18 25,000
-40 -40 100,700
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CODE 23 IS INTERMITTENT. IF NO
ADDITIONAL CODES WERE STORED,
REFER TO "DIAGNOSTIC AIDS" ON
FACING PAGE.
NO
JUMPER CKT 472 TO GROUND.
" S C A N " SHOULD DISPLAY TEMP.
OVER130°C.
DOES IT?
YES NO
OPEN SENSOR
GROUND CIRCUIT,
FAULTY CONNECTION
OR FAULTY ECM.
OPEN CKT 472,
FAULTY CONNECTION
OR FAULTY ECM.
CLEAR CODES AND CONFIRM " C L O S E D L O O P " OPERATION AND NO "SERVICE ENGINE S O O N " LIGHT.
2-25-87
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