Pontiac Fiero 1988 Service Manual page 1004

VEHICLE SPEED SENSOR
T R O U B L E S H O O T I N G H I N T S
° Try the following check before doing the Sys-
tem Diagnosis.
Check the RADIO Fuse by operating the
Radio.
• Go to System Diagnosis for diagnostic tests.
S Y S T E M DIAGNOSIS
• Do the tests
listed
for your symptom in the
Symptom Table below.
• Tests follow the Symptom
Table.
SYMPTOM TABLE
SYMPTOM
FOR DIAGNOSIS
Speedometer does
not operate
properly, ECM Code
24 is not set
Replace Instrument
Cluster, see Section
8C for removal and
replacement
procedures
ECM Code 24 is set,
Speedometer
operates properly
Do Test B
Speedometer does
not operate
properly, ECM Code
24 is set
Do Test A
Cruise Control (if
equipped) does not
operate properly,
ECM Code 24 is not
set
Do Test B
Power Steering does
not operate
properly, ECM Code
24 is not set
Do Test C
C O M P O N E N T L O C A T I O N
Assembly Line Diagnostic Link
(ALDL) Connector In console, near rear of shifter
Cruise Control Module Under console, near radio.
Electro-Hydraulic Power Steering
(EHPS) Controller Lower LH side of front compartment
Electronic Control Module (ECM). . . Between seats, on front of rear bulkhead
Fuse Block. Behind LH side of I/P
Vehicle Speed Sensor RH end of transaxle
C100 (34 cavities) LH side of front bulkhead, right of brake master
cylinder
C203 (15 cavities) Between seats, in front of rear bulkhead
C245 (8 cavities) Beneath center console
G504 (VIN 9) LH top of engine, below throttle body
G504 (VIN R) TopLH front of engine, above Starter Solenoid..
S201 Main harness, above steering column
S216 Main harness, behind center I/P
S504 Engine harness, under rear console. . . . . . . . . . . .
Page-Figure
201- 5-B
201-
9-D
201- 3-D
201- 5-B
201-
6-D
201- 1-A
201-13-A
201- 5-A
201- 3-A
201- 2-A
201- 7-A
201-15-A
201- 5-A
A: VEHICLE SPEED SENSOR BUFFER
T E S T ( T A B L E D
(Continued from previous column)
Measure: VOLTAGE
At: INSTRUMENT CLUSTER CONNECTOR
C1 f Disconnected)
Condition:
• Ignition
Switch: RUN
Measure
Between
Correct
Voltage
For Diagnosis
T (YEL/BLK)
& Ground
Battery Seel
T (YEL/BLK)
&P(BLK/
WHT)
Battery
See 2
• If both voltages are correct, go to Table 2.
1. Check/repair YEL/BLK and YEL (43)
wires for an open (see schematic).
2. Check/repair BLK/WHT and BLK (450)
wires for an open (see schematic). Check
that ground G504 is clean and tight.
(Continued in next column)
If your symptom is not listed in the Symp-
tom Table, perform all the tests.
(Continued on next page)