Pontiac Fiero 1988 Service Manual page 630

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (PORT) 6E3-A-47
CODE 34
MANIFOLD ABSOLUTE PRESSURE
(MAP) SENSOR CIRCUIT
(SIGNAL VOLTAGE LOW-HIGH VACUUM)
2.8L "P" SERIES (PORT)
©
• ENGINE IDLING.
DOES " S C A N " DISPLAY MAP B E L O W .25 VOLTS?
©
YES
• IGNITION " O F F " .
• DISCONNECT SENSOR ELECTRICAL CONNECTOR.
• JUMPER HARNESS TERMINALS " B " TO "C".
• IGNITION " O N " .
• MAP VOLTAGE SHOULD READ OVER 4 VOLTS.
DOES IT?
NO
T
CODE 34 IS INTERMITTENT.
IF NO ADDITIONAL CODES WERE
STORED, REFER TO "DIAGNOSTIC
AIDS" ON FACING PAGE.
NO YES
©
IGNITION " O F F " .
REMOVE JUMPER WIRE.
PROBE TERMINAL " B " (CKT 432) WITH A
TEST LIGHTTO 12 VOLTS.
IGNITION " O N " .
" S C A N " SHOULD READ OVER 4 VOLTS.
DOES IT?
YES
FAULTY CONNECTION
OR SENSOR.
NO
CKT 416 OPEN OR SHORTED TO
GROUND OR FAULTY ECM.
CKT 432 OPEN OR SHORTED TO
GROUND OR FAULTY ECM.
IGNITION "ON" ENGINE STOPPED VOLTAGES
ALTITUDE
Meters Feet
VOLTAGE RANGE
Below 305 Below 1,000 3.8—5.5V
305— 610 1,000-2,000 3.6—5.3V
610— 914 2,000-3,000 3.5—5.1V
914-1219 3,000-4,000 3.3—5.0V
1219-1524 4,000-5,000 3.2—4.8V
1524-1829 5,000-6,000 3.0—4.6V
1829-2133 6,000-7,000 2.9—4.5V
2133-2438 7,000-8
f
000 2.8—4.3V
2438-2743 8,000-9,000 2.6—4.2V
2743-3048 9,000-10,000 2.5—4.0V
LOW ALTITUDE = HIGH PRESSURE = HIGH VOLTAGE
6-17-87
7 S 3 2 1 1 - 6 E