Pontiac Fiero 1988 Service Manual page 498

DRIVEABILITY AND EMISSIONS - FUEL INJECTION (TBI) 6E2-A-43
CODE 33
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR CIRCUIT
(SIGNAL VOLTAGE HIGH - LOW VACUUM)
2 . 5 L " P " SERIES (TBI)
©
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IF ENGINE IDLE IS ROUGH, UNSTABLE OR INCORRECT,
CORRECT BEFORE USING CHART.
SEE SYMPTOMS IN SECTION B.
ENGINE IDLING.
DOES "SCAN" DISPLAY A MAP OF 4.0 VOLTS OR OVER?
YES
• IGNITION "OFF".
• DISCONNECT MAP SENSOR ELECTRICAL CONNECTOR.
• IGNITION "ON".
• "SCAN" SHOULD READ A VOLTAGE OF 1 VOLT OR LESS.
DOES IT*
YES
• PROBE CKT 469 WITH A TEST LIGHT TO 12 VOLTS.
• TEST LIGHT SHOULD LIGHT.
DOES IT?
YES
NO
CODE 3 3 IS INTERMITTENT.
IF NO ADDITIONAL CODES WERE
STORED, REFER TO DIAGNOSTIC
AIDS ON FACING PAGE.
1
NO
CKT 432 SHORTED TO VOLTAGE.
SHORTED TO CKT 416, OR
FAULTY ECM.
NO
PLUGGED OR LEAKING
SENSOR VACUUM HOSE OR
FAULTY MAP SENSOR.
OPEN CIRCUIT 469.
IGNITION " O N " ENGINE STOPPED VOLTAGES
Meters
Below 305
305—610
610— 914
914-1219
1219-1524
1524-1829
1829-2133
2133-2438
2438-2743
2743-3048
ALTITUDE
Feet
Below 1,000
1,000-2,000
2,000-
3.000-
4,000-
5,000-
6,000-
7,000-
3,000
•4,000
•5.000
•6,000
•7.000
8,000
8,000-9.000
9.000-10,000
VOLTAGE RANGE
2.9-
2.8-
2.6-
- 5 . 5 V
-5.3V
-5.1V
-5.0V
- 4 . 8 V
- 4 . 6 V
- 4 . 5 V
-4.3V
-4.2V
- 4 . 0 V
LOW ALTITUDE = HIGH PRESSURE = HIGH VOLTAGE
5-1-86
7S 3210-6E