Pontiac Fiero 1988 Service Manual page 500

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (TBI) 6 E 2 - A - 4 5
CODE 34
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR CIRCUIT
( S I G N A L V O L T A G E L O W - H I G H V A C U U M )
2.5L "P" SERIES (TBI)
1 ) • ENGINE IDLING.
DOES " S C A N " DISPLAY MAP BELOW .25 VOLTS?
©
IGNITION " O F F " .
DISCONNECT SENSOR ELECTRICAL CONNECTOR.
JUMPER HARNESS T E R M I N A L S ' ^ " TO " C " .
IGNITION " O N " .
MAP VOLTAGE SHOULD READ OVER 4 VOLTS.
DOES IT?
NO
IE
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.
9 PROBE TERMINAL " B " (CKT 432) WITH A
TEST LIGHT TO 12 VOLTS.
• IGNITION " O N " .
• " S C A N " SHOULD READ OVER 4 VOLTS.
DOES IT?
FAULTY CONNECTION
OR SENSOR.
CKT 416 OPEN OR SHORTED TO
GROUND OR FAULTY ECM.
CIRCUIT 432 OPEN OR SHORTtD TO
GROUND OR FAULTY ECM.
IGNITION "ON" ENGINE STOPPED VOLTAGES
ALTITUDE VOLTAGE RANGE
Meters Feet
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
7,000-8.000 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