1988 PONTIAC FIERO check engine

COOLANT FAN I g
TROUBLESHOOTING HINTS
@ Try the following checks before doing the Sys-
tem Check.
1. Check the CIH-FAN Fuse if the Coolant Fan
does not run.
2. Check that ground 6112 (V6 VIN S), 6117
(V8 VIN E) or 6104 (V8 VIN F and V8 VIN
8) is clean and tight.
3. Check the Fusible Link (see schematic).
4.
If the Coolant Fan runs with the Ignition
Switch OFF, replace the Coolant Fan Relay.
@ Go to System Check for a guide to normal
operation.
Go to System Diagnosis for diagnostic tests.
SYSTEM CHECK
Use the System Checlc Table as a guide to
normal operation.
SYSTEM CHECK TABLE
I ACTION I NORMALRESULT 1
COMPONENT LOCATION Page-Figure
Assembly Line Diagnostic Link
(ALDL) Connector .............. On bottom of IIP hush panel, to right of steering
column
Auxiliary Coolant Fan Relay
....... RH front side of engine compartment. ......... 201- 5-A
Auxiliary Coolant Fan Switch
...... Lower RN rear of engine .................... 201- 6-A
Coolant Fan Relay (VIN
E). ........ LH rear corner of engine compartment, on relay
bracket
................................. 201- 3-A
Coolant Fan Relay (VIN F) (VIN 8)
. . Front of engine compartment, RN side of
radiator support.
......................... 201- 5-A
Coolant Fan Relay (VIN S)
......... LH rear corner of engine compartment, on relay
................................. bracket 201- 0-A
Coolant Fan Switch
.............. Lower RH rear of engine, above starter solenoid . 201- 4-A
Coolant Temperature Sensor (VIN F)
(VIN 8).
....................... Top LW front of engine. ..................... 201- 8-C
Coolant Temperature Sensor (VIN S) Top LH front of intake manifold.
............. 201- 0-A
Electronic Control Module (ECM)
... Behind RN side of IIP ...................... 201-12-B
Fan Pressure Switch (VIN F) (VIN 8) Lower RH side of engine, on
AIC line .......... 201- 5-A
Fan Pressure Switch (VIN S)
....... Lower RN front of engine compartment, on AIC
line .................................... 201- 1-A
Fuse Block.
..................... Behind LN side of IIP, below light switch. ...... 201-10-A
Fusible Link
N (VIN E) ........... RH front of engine compartment, at Junction
Block ................................... 201- 3-B
Fusible Link N (VIN F) (VIN 8).
.... LN front of engine compartment, behind battery 201- 5-C
Fusible Link
J (VIN S) ............ RN side of radiator support, at Junction Block .. 201- 1-A
Redundant Cooling Fan Switch.
.... Top RW rear of engine ...................... 201- 1-6
C102 (4 cavities) ................. Center front of dash. ....................... 201-14-A
6104 (6 cavities)
................. Front of engine compartment, RH side of
................................ radiator. 201- 5-A
C204 (4 cavities) ................. Above LH rear corner of engine .............. 201- 0-A
C207 (15 cavities)
................ Behind RH side of IIP, near ECM ............. ,201-13-A
C224 (6 cavities) ................. Center of IIP, behind AIC control ............. 201-14-B
6104
.......................... On radiator support, behind RN headlights. .... 201-16-A
6112 (VIN E)
................... Rear of LN cylinder head. ................... 201- 3-C
6112 (VIN S)
.................... Rear of LH cylinder head. ................... 201- 0-C
6118 (VIN F) (VIN 8)
............. Rear of RH cylinder head. ................... 201- 5-A
6118 (VIN S)
.................... Rear of RH cylinder head. ................... 201- 1-C
(Continued on next page)
With
the engine cold
and idling, turn the
AIC Selector to
NORM (if equipped
with Ale)
VIN E: Coolant Fan
turns on
VIN S, VIN
F &
VIN 8: Coolant Fan
(and Auxiliary
Coolant Fan-if
equipped) turns on
when
A/C Control
Head Pressure
exceeds 233 psi
(1600
kPa)
(Continued on next page)

COOLANT FAN rn
6: COOLANT FAN SHORT TEST
1. With the Ignition Switch in RUN, remove
the Redundant Cooling Fan Switch connec-
tor.
If the Coolant Fan does not turn off, go to
Step
2.
If the Coolant Fan turns off, replace the
Redundant Cooling Fan Switch.
2. Remove the CIR-FAN Fuse.
If the Coolant Fan turns off, check the DK
GRNIWHT
(335) wires for a short to ground.
Refer to Section 6E for ECM diagnosis if the
wires are OK.
a If the Coolant Fan does not turn off, replace
the Coolant Fan Relay.
SYSTEM DlAGNOSlS
V8 VIN F AND V8 VIN 8
Do the tests listed for your symptom in the
Symptom Table below.
Tests follow the Symptom Table.
SYMPTOM TABLE
I SYMPTOM I FORDIAGNOSIS I
I Do Test A I
I not run at aB I I
Coolant Fan runs at
all times with the
A/C off and engine
cool
(Continued in next column)
Do
Test
B
Auxiliary Coolant
Fan does not run at
all
:Continued from previous column)
Fan runs at
all times
with
AIC off and the
Do Test C (Continued
from previous column)
GRNIWNT
(335) wire for an open. If wire
is OK, go to Section 6E for ECM diag-
nosis.
1. Go to Table 3.
A: COOLANT FAN OPEN TEST
(TABLE
1)
At: ALDL CONNECTOR
Condition:
I B &Ground I I See l' I
Connect
Between
If the result is correct, go to Section 6E
for ECM diagnosis.
A: COOLANT FAN OPEN TEST (TABLE
2)
Correct Result
I
Connect: FUSED JUMPER
At: COOLANT FAN RELAY CONNECTOR For
Diagnosis
(Connected)
Condition: lgnition Switch: RUN
Jumper
I Correct Result I For Diagnosis I Between
(DK GRN1 Coolant Fan
WHT) & See 1
1 Ground 1 runs 1 1
A: COOLANT FAN OPEN TEST (TABLE
3) I
Connect: TEST LAMP
At: COOLANT FAN RELAY CONNECTOR
(Disconnected)
Condition:
Connect I Correct Rewn I For Diagnosis I I Between
C (BRN) &
Ground
If the results are correct, go to Table
4.
1. Check CIH-FAN Fuse and BRN (250) wire
for opens.
2. Check Fusible Link H and ORN (440) wire
for opens.
E (ORN)
&
Ground
(Continued in next column)
(Continued on next page)
Test Lamp
lights See
1
Test
Lamp
lights See 2

VEHICLE SPEED SENSOR
TROUBLESHOOTING HINTS
0 Try the following checks before doing the
System Diagnosis
.
1
. Check the Gages Fuse by observing the Brake
Indicator when applying the Parking Brake
wrth the Ignition Switch in RUN (engine not
running)
.
2 . Check ground 6118 .
3 . If only the Speedometer or only the Odometer
does not work. replace the suspect item
.
Go to System Diagnosis for diagnostic tests .
SYSTEM DlAGNOSlS
Do the tests listed for your symptom in the
Symptom Table below
.
Tests follow the Syrnptom Table .
COMPONENT LOCATION Page-Figure
Cruise Control Module
............ Behind RN side of IlP ...................... 201-11-A
Electronic Control Module (ECM)
... Behind RN side of IIP ...................... 201-12-B
Fuse Block
...................... Behind LN side of IIP. below light switch ....... 201-10-A
Vehicle Speed Sensor
............. Lower LEI rear of transmission ............... 201- 8-D
Vehicle Speed Sensor Buffer
....... Behind RH side of IIP. near ECM ............. 201-13-A
ClOO (42 cavities) ................ LN front of dash. left of brake master cylinder .. 201- 0-A
C207 (15 cavities) ................ Behind RH side of IIP. near ECM ............. 201-13-A
C209 (2 cavities)
................. Behind RN side of IIP. left of Cruise Control
................................. Module 201-11-A
6118 (VIN E)
................... Rear of RH cylinder head .................... 201- 5-B
6118 (VIN F) (VIN 8) ............. Rear of RN cylinder head .................... 201- 5-A
6118 (VIN S)
.................... Rear of RN cylinder head .................... 201- 1-C
S143 (VINE)
.................... Engine harness. RH front of dash ............. 201- 2-A
S143 (VIN F) (VIN
8) ............. Engine harness. RN front of dash ............. 201- 6-A
S143 (VIN S)
.................... Engine harness. center front of dash ........... 201- 1-A
S202
........................... IIP harness. behind RH side of IIP ............ 201-13-A
S204
........................... IIP harness. behind instrument cluster ......... 201-10-A
S217 ........................... IIP harness. behind center of IIP .............. 201-10-A
SYMPTOM TABLE
I SYMPTOM I FOR DIAGNOSIS I
=liter does not operate properly. ECM I Do Test B
code 24 is not set
ECM Code
24 is set. Speedometer is good
e If your symptom is not listed in the Symptom Table. pedorm all the tests .
Do Test C
See Section 6E of Service Manual
Speedometer does not operate properly. and ECM
Code
24 is set
Cruise Control does not operate properly. ECM
Code
24 is not set Do
Test
A
Do Test D

CRUISE CONTROL
TROUBLESHOOTING HINTS
Try the following checks before doing the Sys-
tem Check
.
1 . Check vacuum hose for leaks. kinks. andlor
restrictions . Also check Cruise Control
Servo linkage
. Refer to Section 9 for vacuum
hose routing and servo linkage adjustments
.
2 . If the system works except for the Tap-Up
and
TapDown functions. replace the Cruise
Control Module
.
Go to System Check for a guide to normal
operation
.
Go to System Diagnosis for diagnostic tests .
SYSTEM CHECK (ROAD TEST)
Use the System Check Table as a guide to
normal operation
.
COMPONENT LOCATION Page-Figure
Brake Switch
.................... Above brake pedal. on brake pedal support ..... 201- 9-A
Check Valve
..................... Behind engine. to right of master brake cylinder . 201-15-A
Clutch Switch
................... Above clutch pedal. on clutch pedal support .... 201-10-B
Cruise Control Module
............ Behind RH side of IIP ...................... 201-11-A
Cruise Control Servo .............. LH front of engine compartment ............. 201-15-A
Fuse Block
...................... Behind LH side of IIP. below light switch ....... 201-10-A
Vacuum Release Valve
............ Above brake pedal. on brake pedal support ..... 201-10-B
Vacuum Tank ................... Lower LH front corner of engine compartment .. 201-15-A
Vehicle Speed Sensor Buffer
....... Behind RH side of IIP. near ECM ............. 201-13-A
C203 (6 cavities) ................. Behind LH side of IIP. at base of steering column 201-11-A
C207 (15 cavities) ................ Behind RH side of IIP. near ECM ............. 201-13-A
C209 (2 cavities) ................. Behind RH side of IIP. left of Cruise Control
................................. Module 201-11-A
C223 (4 cavities) ................. Behind LH side of IIP. at base of steering column 201-11-A
6102 .......................... LN rear corner of engine compartment ......... 201-15-A
6118 (VIN E)
................... Rear of RH cylinder head .................... 201- 5-B
6118 (VIN F) (VIN 8)
............. Rear of RN cylinder head .................... 201- 5-A
6118 (VIN S)
.................... Rear of RN cylinder head .................... 201- 1-C
S143 (VIN E) .................... Engine harness. RH front of dash ............. 201- 2-A
S143 (VIN
F) (VIN 8) ............. Engine harness. RN front of dash ............. 201- 6-A
S143 (VIN S)
.................... Engine harness. center front of dash ........... 201- 1-A
S204
........................... IIP harness. behind instrument cluster ......... 201-10-A
S217
........................... IIP harness. behind center of IIP .............. 201-10-A
S238
........................... Cruise control harness. near Brake Switch ...... 201-11-A
SYSTEM CHECK TABLE
Car should maintain speed
(Continued on facing page)

CRUISE CONTROL 2
I Slide Cruise Control Switch momentaril~ to RIA I Car should accelerate to former set s~eed I
(Continued from facing page)
--
While cruising, accelerate, then remove foot I car should coast back to set speed
from accelerator
Release Cruise Switch
back to ON
Tap brake pedal
I While cruising, tap Cruise Switch to RIA I Car should increase 1 mph for each tap, up to I
Car should hold new faster speed
Car should coast slower (Cruise disengages)
tap
until 25 mph is reached when cruise
Control will not o~erate I
While cruising, tap Set button
1 Slide Cruise Switch to OFF ten
taps, then system must be reset to a new
speed
Car speed should decrease by
1 mph for each
I Cruise Control turns off 1
0 Refer to System Diagnosis when a result is not normal.
SYSTEM DIAGNOSIS
@ Use the isolation Test below to choose the
proper diagnostic tests.
@ Tests follow the Isolation Test.
Note: Do not press both the SET and RIA
Switches at the same time while the
engine is running. If the Quick Checker
displays
a short light, release the
switches immediately. Shorts can
damage the Quick Checker.
lSOLATlON TEST
Connect: QUICK CHECKER (J-34185, SPECMO QC-3 OR EQUIVALENT) or VOLT-OHMMETER
At: CRUISE CONTROL MODULE CONNECTOR (Disconnected)
Conditions:
@ Ignition Switch: RUN
Test with Quick Checker
(J-34185 or equivalent) or Digital Meter
Test Condition
Cruise Switch OFF
(ISOLATION TEST continued on next page)
All Lights Off
With Quick
Checker,
Correct Response
-
20 VDC
20 VDC
For
Different
Response, Do
Test:
B
Without Quick Checker,
Using a Digital Meter
A&J
M&J
Meter
Range
200 ohms
0 volts
0 volts
Connector
Terminals
J & Ground
A
Correct
Response
0 ohms

CRUISE CONTROL
(ISOLATION
Test
2 3
4
5
6
7
If all
TEST continued from previous page)
Condition
Cruise Switch ON
Cruise Switch ON, Set Switch
pressed
Cruise Switch
in RIA
Cruise Switch ON, drive wheels
turned by hand
Run engine for one minute, then
turn it off. With Ignition Switch in
RUN, and holding Cruise Switch
in
RIA, press Set Switch, wait for
Servo to pull
in and release Set
Switch
Quick Checker not connected
the responses were correct, replace Cruise
With Quick
Checker,
Correct Response
ONIOFF Light On
BRK Light On
VENT Light On
VAC Light On
SPS Light On
RA Light Off
SC Light Off
SC Light On
VAC
& SNORT Lights Off
ONIOFF Light On
RA Light On
VENT & SNORT Lights
Off
VSS Light flashes On and
Off
Vacuum holds the servo
all theway in
-
Control Module and check
Without Quick Checker, For
Using
a Digital Meter Different
Meter
Range
20 VDG
20 VDC
200 ohms
200 ohms
200 ohms
20 VDC
20 VDC
20 VDC
200 ohms
20 VDC
20 VDC
200 ohms
20VDC
Connector Terminals
A&J
G&J
C&J
K&J
F&N
M&J
L&J
L&J
K&J
A&J
M&J
C&J
A&D
Response,
Correct Do
Response Test
Battery voltage B
Battery voltage C
30 to 55 ohms D
30 to 55 ohms E
15 to 25 ohms F
0 volts A
0 volts
A
Battery voltage G
30 to 55 ohms N
Battery voltage A
Battery voltage
I
30 to 55 ohms J
Pulses between
approximately battery
voltage and less than
7 K, L
volts
Connect fused jumper from
CtoMandfromKtoL
before operating switches
200ohms 1 F&J
for proper operation.
Vacuum holds the servo
all the way in M
Over range N

BRAKE VVARNlNG SYSTEM
TROUBLESHOOTING HINTS
0 Try the following checks before doing the
System Diagnosis.
Check the GAGES Fuse and PNKIBLK
(39) wire by observing the VOLTS or
SERVICE ENGINE SOON Indicator with
the Ignition Switch in RUN and the engine
OFF.
0 Go to System Check for a guide to normal
operation.
0 Go to System Diagnosis for diagnostic tests.
SYSTEM CHECK
Use the System Check Table as a guide to
normal operation.
e Refer to System Diagnosis for a list of symp-
toms and diagnostic steps.
SYSTEM CHECK TABLE
RUN position to
BULB TEST
COMPONENT LOCATION Page-Figure
.................. Brake Fluid Level Switch. ......... Below brake fluid reservoir 201-16-A
..................... Fuse Block. Behind
LH side of IIP, below light switch. ...... 201-10-A
................. Ignition Switch. Behind IIP, on
top side of steering column ...... 201- 9-A
Parking Brake Switch.
............ In console, at base of parking brake ........... 201-12-D
................... Release Relay Taped
to IIP harness, behind RH side of IIP. .... 201-13-A
................ (2100 (42 cavities) LR
front of dash, left of brake master cylinder .. 201- 0-A
........................... S204. IIP harness, behind instrument cluster. ........ 201-10-A
.......................... ............... S228. IIP harness, above Fuse Block. 201-10-A
SYSTEM DIAGNOSIS
0 Diagnostic steps for the symptorns listed'in
the following table are listed after the table.
A: BRAKE INDICATOR REMAINS ON
WITH THE
IGNITION SWITCH IN
RUN AND THE PARK BRAKE OFF
(TABLE
1)
SYMPTOM TABLE
A BRAKE Indicator remains on with the
Ignition Switch
in RUN and the park
brake off
B BRAKE Indicator lights with the park
brake applied, but does not light when
brake fluid level is low
C BRAKE Indicator does not light at all
D BRAKE Indicator lights with the Igni-
tion Switch in BULB TEST, but does not
light when the park brake is applied
E BRAKE Indicator lights with the park
brake applied, but does not light when
the Ignition Switch is in BULB TEST
Refer to System Diagnosis when a result is
not normal. Disconnect:
CONNECTOR
At: BRAKE FLUID LEVEL SWITCH
Conditions:
0 Ignition Switch: RUN
0 Park Brake: OFF
Pressure Warning
If the result is correct, refer to Section
5 to
test the Brake Hydraulic System.
Replace the Brake Fluid Level Switch if
the Brake Hydraulic System is OK.
1. Go to Table2.

AIR CONDITIONING: BLOWER CONTROLS
C60, MANUAL
TROUBLESHOOTING
HINTS
Try the following checks before doing the
System Check.
1. Check the HTR A/C Fuse by visual inspection.
2. Check that ground
6112 is clean and tight.
3. Check that Blower Motor connectors and
Blower Relay are mated correctly and firmly
seated.
Go to the A/C System Check in 8A-62 for a
guide to normal operation.
Q Go to System Diagnosis for diagnostic tests.
SYSTEM DIAGNOSIS
Do the tests listed for your symptom in the
Symptom Table below.
Q Tests follow the Symptom Table.
SYMPTOM TABLE
SYMPTOM
Blower runs all the
time (Ignition OFF)
Blower run
all the
time (Ignition OFF)
Blower will not run
in any mode
No Lo speed
operation
COMPONENT LOCATION Page-Figure
Blower High Speed Relay.
......... RH front of dash, near Blower Motor ..........
Blower Motor (With Ale) .......... RH front of dash. ..........................
Blower Resistors (With AIC) ....... RH front of dash, behind strut tower ..........
Fuse Block. ..................... Behind LH side of IIP, below light switch. ......
Fusible Link B (VIN E). ........... Lower RH side of engine, at Starter Solenoid. ...
Fusible Link B (VIN F) (VIN 8) ..... Lower RH side of engine, at Starter Solenoid. ...
Fusible Link B (VIN S). ........... Lower RH side of engine, at Starter Solenoid. ...
(2102 (4 cavities) ................. Center front of dash. .......................
6115 (1 cavity). .................. Center front of dash. .......................
(2202 (1 cavity) .................. Behind. center of IIP, near control head. ........
6112 (VIN E) ................... Rear of LN cylinder head. ...................
6112 (VIN F) (VIN 8) ............. Rear of LH cylinder head. ...................
6112 (VIN S). ................... Rear of LH cylinder head. ...................
Slll ........................... Engine harness, RH rear of engine compartment
S117 (VINE)
.................... Engine harness, RH front of dash. ............
S117 (VIN F) (VIN 8) ............. Engine harness, top center rear of engine. ......
S119. .......................... AIC harness, RH rear of engine compartment ...
DO TEST
B : Blower High
Speed Relay Test
E:
AIC Mode
Selector Test
A: Blower Motor Test
E: A!C Mode Selector
Test
C: Blower Resistors
Test (Continued
from previous column)
A: BLWER MOTOR TEST
Measure: VOLTAGE
At: BLOWER MOTOR CONNECTORS
(Disconnected)
Conditions:
Ignition Switch: RUN
Q NC Mode: VENT
Blower Switch:
HI
If your symptom does not appear in the SY~P- (A: BLOWER MOTOR TEST continued on fat- tom Table, perform all of the tests. ing page)
Hi speed only
Blower runs in Lo at
M1 or M2
No Hi speed
operation
B: Blower High
Speed Relay Test
D: Blower Switch
Test
D: Blower Switch
Test
B: Blower High
Speed Relay Test
D: Blower Switch
I Test 1
(Continued in next column)