1988 PONTIAC FIERO fuel pump

INDEX
SECTION PACE
....................... Detonation... B-4
.................. Diagnostic Procedure 2-5
................ Diagnostic Circuit Check A-8
..................... Dieseling. Run On B-6
Distributor Reference Signal
................. General Description C1-4
......................... Diagnosis C1-5
E
.................... ECM Terminals ... A-6
.................. ECM Wiring Diagram A3-A6
..................... EGR Control Valve C7-1
................. Valve Identification C7-2
................... Diagnosis. Service C7-2
EGR Control Solenoid
.................. C7-3
Parts Information
................... C7-3
......................... EGR Check C7-4
Electronic Control Module
................. General Description C1-I
......................... Diagnosis C1-5
............................ Service C1-6
..................... Function Check C1-6
Electronic Spark Control (ESC) System
................. General Description C5-1
................... Diagnosis. Service C5-I
Engine Coolant Temperature Sensor
................. General Description C1-2
......................... Diagnosis C1-5
Engine Cranks But Won't Run
............ A-14
........................ Engine Knock C5-4
.......................... ESC Module C5-1
.......................... ESC Sensor C5-1
..................... ESC System Check C5-4
ESTIlgnition System ................... C4-1
Evaporative Emission
Conirol System
General Description
................. C3-1
.......................... Diagnosis C3-2
Exhaust Emissions Excessive (Odors)
....... B-7
Exhaust Gas Recirculation (EGR) System
..... C7-1
Exhaust System Check Restricted
......... B-8
Fuel Control System
General Description
................. C2-1
Diagnosis. Parts Information
........... C2-6
Fuel Cutoff Mode
.................... C2-2
Fuel Meter Body Assembly
.............. C2- 1 I
Fuel Injectors ........................ C2-3
Fuel Meter Cover Assembly
.............. C2-8
Fuel Pressure Connection Assy
............ C2- 10
SECTION PAGE
........... Fuel Pressure Relief Procedure C2-6
.............. Fuel Pump Electrical Circuit C2-5
...................... Fuel Pump Relay C2-15
.................. Fuel System Diagnosis A- 18
............... Fuel System Pressure Test C2-7
......... Fuel Tank Pressure Control Valve C3-3
................... Fuel
Vapor Canister C3-3
G
.................. General Information 2-5
H
.......................... Hard Start B-2
.......... HE1 High Energy Ignition System C4-1
.......................... Hesitation
B-4
............ ldle Air Control System Check
.................. ldle Air Control Valve
......................... Diagnosis
....................... Service (EST)
Ignition System
................. General Descr~ption
......................... Diagnosis
Check
............................
........................ Incorrect ldle
.................. lnformation Sensors
................... Injector Balance Test
........................ Intermittents
......................... Introduction
Knock Sensor
................. General Description C1-4
......................... Diagnosis C1-6
....................... Lack Of Power B-3
Light. Manual Transmission Shift
......... C8-8
Light. Service Engine Soon
.............. A-10
Manual Transmission Electrical Diagnosis
... C8-10
Manual Transmission Overdrive Relay ..... C8-3
MAP Sensor
General Description
................. C1-2

DRIVEABILITY AND EMISSIONS 2.8L (VIN 5). 5.OL (VIN F) & 5.7L (VIN 8) 6E3-1
SECTION 6E3
TY AND EM
THIS SEC"T0N APPLIES TO:
2.8L LB8 (VlN S) "F" SERIES
5.OL LB9 (VIN F ) "F'" SERIES
5.7L L98 (VIN 8) ""F3"lES
CONTENTS
INTRODUCTION
2.8L (VIN 5). 5.OL (VIN F) & 5.7L (WIN 8)
General Description ................... 8
Diagnosis Procedure ................... 8
SECTION A . DIAGNOSTIC CHARTS
2.8L (VIN S)
Table of Contents .................... A-1
Engine Components and Wiring
Component Locations
............... A-2
Wiring Diagrams (1 of 3) ............. A.3.4. 5
ECM Terminal End View .............. A-6
Diagnostic Circuit Check ................ A-8
No "Service Engine Soon" Light
Chart A-I
......................... A-10
No ALDL Data . "Service Engine Soon"
Light "ON" Steady (Won't Flash Code 12)
Chart A-2
......................... A-12
Engine Cranks But Won't
.... Chart A-3 (1 of 2)
Fuel System Diagnosis Run ................ A-14
. ChartA-7(1 of
2) ................... A-18
Cold Start Valve
Chart A-9
......................... 8-22
. .... Code 13 Oxygen Sensor Circuit (Open) A-24
Code 14 . Coolant Temperature Sensor Circuit
. (High Temp Indicated) .............. A-26
Code 15 . Coolant Temperature Sensor Circuit
(Low Temp
. Indicated) .............. A-28
Code 2 1 . Throttle Position Sensor (TPS) Circuit
(Signal Voltage High)
........ , ...... A-30
Code 22 . Throttle Position Sensor (TPS) Circuit
(Signal Voltage Low)
......... , ...... A-32
Code 23 . Manifold Air Temperature (MAT) Sensor
. Circuit (Low Temp Indicated) .......... A-34
Code 24 . Vehicle Speed Sensor
(VSS) Circuit ....................... A-36
Code 25 . Manifold Air Temperature (MAT)
Sensor Circuit (High Temp
. Indicated) .... A-38
Code 32 . EGRSystem Failure ............ A-40
Code 33 . Mass Air Flow (MAF) Sensor Circuit
(GMISEC High) .................... A-42
Code 34 . Mass Air Flow (MAF) Sensor Circuit
(GMISEC Low) .................... A-44
Code 41 . Cylinder Select Error ........... A-46
Code 42 . Electronic Spark Timing Fault .... A-48
Code 44 . Oxygen Sensor Circuit
(Lean Exhaust Indicated)
............. A-50
Code 45 . Oxygen Sensor Circuit
(Rich Exhaust Indicated)
.............. A-52
Code 54 . Fuel Pump Circuit (Lowvoltage) . . A-54
Code 5 1 . PROM Error
(Faulty or Incorrect PROM)
............ A-56
Code 52 . CALPAK Error
(Faulty or Incorrect CALPAK)
.......... A-56
Code 53 . System Over Voltage ........... A-56
Code 55 . ECM Error ................... A-56
SECTION B . SYMPTOMS
2.8L (WIN 5)
Table of Contents .................... B-1
Before Starting ...................... B-1
Intermittents ........................ B-2
Hard Start .......................... 8-2
Hesitation. Sag. Stumble ............... 8-3
Surges and/or Chuggle ................. 8-3
Lack of Power. Sluggish. or Spongy ........ B-4
DetonationJSpark Knock ............... 6-4
Cuts Out. Misses ...................... 8-5
Backfire ............................ 8-5
Poor Fuel Economy .................... B-6
Dieseling. Run.On ..................... 8-6
Rough. Unstable. or lncorrect Idle. Stalling . . €3-6
Excess~ve Exhaust Emissions or Odors ...... 8-7
Restr~cted Exhaust System Check
Chart
B-I ......................... 8-63

DRlVEABlLlTVAND EMISSIONS 2.8L (VIN S). 5.OL (VIN F) & 5.7L (VIN 8) 6E3-3
.................... FUEL PUMP ELECTRICAL CIRCUIT ....... C2-4 CANISTER HOSES C3-3
................ DIAGNOSIS ......................... C2-5 PARTS INFORMATION C3-3
FUEL CONTROL SYSTEM .............. C2-5 Canister Purge Valve Check
......................... IDLE AIR CONTROL VALVE ............ C2-5 Chart C-3 C3-4
ON-CAR SERVICE
..................... C2-5
.... PORT FUEL INJECTION COMPONENTS C2-5
FUEL PRESSURE RELIEF PROCEDURE ..... C2-5
Plenum ........................ C2-5
Fuel Rail & Pressure Regulator Assembly . C2-5
FUEL RAIL SERVICE ................. C2-6
UNIT SERVICE PROCEDURES ........... C2-6
COLD START TUBE & VALVE ASSEMBLY ... C2-7
FUEL PRESSURE CONNECTION ASSEMBLY . C2-7
FUEL BLOCK AND SEAL ............... C2-9
FUEL INJECTORS .................... C2-9
Port Injectors wl Injector Retaining Clips C2-9
Fuel Pressure Regulator ............ C2-10
PORT INJECTORS ................... C2-10
PRESSURE REGULATOR ............... C2-10
COLD START FUEL INJECTION SWITCH ...
THROTTLE BODY ...................
THROTTLE BODY SERVICE IDENTIFICATION
MINIMUM IDLE SPEED ADJUSTMENT
....
UNIT REPAIR PROCEDURES ............
IDLE AIR CONTROL VALVE
ASSEMBLY
& GASKET ................
IDLE AIR I VACUUM SIGNAL
HOUSING ASSEMBLY
................
COOLANT CAVITY COVER & O-RING .....
IDLE AIR CONTROL I COOLANT
COVER ASSEMBLY
..................
FUEL PUMP RELAY ..................
OIL PRESSURE SWITCH ...............
PARTS INFORMATION .................
Injector Balance Test
Chart C-2A
........................
Idle Air Control
Chart C-2C
........................
SECTION C3 . 2.8L (WIN S)
EVAPORATIVE EMISSION CONTROL (EECS) SYSTEM
GENERAL
DESCRIPTION ............... C3-1
PURPOSE ........................ C3-1
VAPOR CANISTER ................... C3-1
EVAPORATIVE EMISSION SYSTEM ...... C3-1
TANK PRESSURE CONTROL VALVE ...... C3-2
.... RESULTS OF INCORRECT OPERATION C3-2
DIAGNOSIS
........................ C3-2
VISUAL CHECK OF CANISTER .......... C3-2
FUNCTIONAL TEST
Vapor Canister Purge Valve
........ C3-2
..... Fuel Tank Pressure Control Valve C3-2
ON-CAR SERVICE
................. C3-3
FUEL VAPOR CANISTER WR ............ C3-3
FUEL VAPOR CANISTER SOLENOID WR .... C3-3
SECTION C4 . 2.8L (VIN S)
IGNITION
SQSTEMIEST
................ GENERAL DESCRIPTION C4-1
......................... PURPOSE C4-1
OPERATION ....................... C4-1
RESULTS OF INCORRECT OPERATION .... C4-2
DIAGNOSIS
......................... C4-2
CODE 12 .......................... C4-2
ON-CAR SERVICE ..................... C4-2
SETTING TIMING .................... C4-2
HOW CODE 42 IS DETERMINED ......... C4-2
PARTS INFORMATION ................. C4-2
Ignition System Check
Chart C-4A
........................ C4-4
SECTION C6 . 2.8L (VIN S)
AIR INJECTION REACTION (A.I.R.) SYSTEM
MANUAL TRANSMISSION ONLY
............... GENERAL DESCRIPTION C6-1
........................ PURPOSE C6-1
............. A.I.R. PUMP OPERATION C6-I
..................... AIR CONTROL C6-1
.......... Electric Air Control Valve C6-1
............... Deceleration Valve C6-2
... RESULTS OF INCORRECT OPERATION C6-2
........................ DIAGNOSIS C6-2
............. OPERATIONAL CHECKS C6-2
.................... A.I.R. Pump C6-2
................. Hoses and Pipes C6-2
............... Deceleration Valve C6-3
.................... Check Valve C6-3
.................... ON-CAR SERVICE C6-3
...................... DRIVEBELT C6-3
....................... A.I.R. PUMP C6-3
............... AIR CONTROL VALVE C6-3
.................... CHECKVALVE C6-4
DECELERATION VALVE .............. C6-4
................ PARTS INFORMATION C6-5
Electric Control (Divert)
(Manual Transmission)
........................ Chart C-6 C6-6
SECTION C7
. 2.8L (VIN S)
EXHAUST GAS RECIRCULATION (EGR) SYSTEM
GENERAL DESCRIPTION
................ C7-1
......................... PURPOSE C7-1
....................... OPERATION C7-I
ELECTRONIC VACUUM REGULATOR
........................... VALVE C7-1
................... PORT EGR VALVE C7-2
........... EGR VALVE IDENTIFICATION C7-2
... RESULTS OF INCORRECT OPERATION C7-2
......................... DIAGNOSIS C7-3

6E3-4 2.8L (VIN S) . 5.OL (VIN F) & 5.7L (VIN 8) DRIVEABILITY AND EMISSIONS
ON-CAR SERVICE ..................... C7-3
EGRVALVE
........................ C7-3
EGR Manifold Passage
............... C7-3
EGR Manifold Passage
............... C7-4
ELECTRONIC VACUUM REGULATOR
VALVE
.......................... C7-4
EVRV FILTER REPLACEMENT
.......... C7-4
PARTS INFORMATION
................. C7-4
Exhaust Gas Recirculation Check
Chart C-7
......................... C7-6
SECTION
C8 . 2.8L (VIN S)
TRANSMISISON CONVERTER CLUTCH (TCC) SYSTEM
AND MANUAL TRANSMISSION SHIFT LIGHT
GENERAL DESCRIPTION
................ C8-1
PURPOSE ......................... C8-1
OPERATION ....................... C8-1
DIAGNOSIS
......................... C8-1
SHIFT LIGHT (M/T) DESCRIPTION ........ C8-1
DIAGNOSIS
......................... C8-1
ON-CAR SERVICE ..................... C8-1
Automatic Transmission
Converter Clutch (TCC)
. (1 of 2)
Chart C-8
......................... C8-2
Transmission Converter Clutch
(TCC) Electrical Diagnosis
. (2 of 2)
Chart C-8
......................... C8-4
SECTION C10 . 2.8L (WIN S)
ECM CONTROLLED AIR CONDITIONING
GENERAL DESCRIPTION
................ C10-1
OPERATION ....................... C10-1
DIAGNOSIS ......................... C10-1
ON-CARSERVICE ..................... C10-1
FJC Clutch Control
Chart C-
1 0 ........................ C10-2
SECTION C12 . 2.8L (VlN S)
COOLING FAN CONTROL
GENERAL DESCRIPTION
................ C12-1
OPERATION ....................... C12-1
DIAGNOSIS
......................... C12-1
PARTS INFORMATION ................. C12-1
Cooling Fan Control Circuit (1 of 2)
Chart
C- 12 ........................ C12-2
Cooling Fan Control Circuit (2 of 2)
Chart C-12
........................ C12-4
SECTION C13
. 2.8L (WIN S)
POSITIVE CRANKCASE VENTILATION (PCV)
GENERAL DESCRIPTION
................ C13-1
RESULTS OF INCORRECT OPERATION
.... C13-1
DIAGNOSIS
......................... C13-1
FUNCTIONALCHECK OF PCV VALVE .... C13-1
ON-CAR SERVICE
..................... C13-2
PARTS INFORMATION
................. C13-2
SEC"T0N A . DIAGNOSTIC CHARTS
5.OL (VIN F) & 5.7L (VIN 8)
.................... Table of Contents A-1
Engine Components and Wiring
............... Component Locations A-2
Wiring Diagrams
(1 of 4) ............. A-3
ECM Terminal End View
.............. A-7
Diagnostic Circuit Check
................ A-8
No "Service Engine Soon" Light
......................... Chart A-1 A-10
No ALDL Data
. "Service Engine Soon"
Light "ON" Steady (Won't Flash Code 12)
Chart A-2
......................... A-12
Eng~ne Cranks But Won't Run
Chart A-3
(1 of 2) ................... A-14
Fuel System
Diagnos~s
Chart A-7 (1 of 2) ................... A-18
Cold Start Valve
Chart A-9
......................... A-22
Code 13
. Oxygen Sensor Circuit (Open) .... A-24
Code 14
. Coolant Temperature Sensor Circuit
(High Temp
. Indicated) .............. A-26
Code
1 5 . Coolant Temperature Sensor C~rcuit
. .............. (Low Temp Ind~cated) A-28
Code 21
. Throttle Pos~tlon Sensor (TPS) Circuit
(Signal Voltage High)
............... A-30
Code 22
. Throttle Pos~t~on Sensor (TPS) Circuit
................ (Signal Voltage Low) A-32
Code 23
. Manifold Air Temperature (MAT) Sensor
C~rcuit (Low Temp . Indicated) .......... A-34
Code 24
. Vehicle Speed Sensor
....................... (VSS) Circuit A-36
Code 25
. Manifold Air Temperature (MAT)
Sensor Circuit (High Temp
. Indicated) .... A-38
. ............ Code 32 EGR System Failure A-40
Code 33
. Mass Air Flow (MAF) Sensor Circuit
.................... (GMISECHlgh) A-42
Code 34
. Mass Air Flow (MAF) Sensor Circu~t
.................... (GMISEC Low) A-44
Code 36 Mass Air Flow
(MAF) Sensor
.. ..... ........... Burn-Off Circuit , , A-46
. ........... Code 41 Cyl~nder Select Error A-48
... . Code 42 Electronic Spark Timing Circuit A-50
Code 43 Electronic Spark Control
(ESC)
C~rcuit ....................... A-52
Code 44
. Oxygen Sensor Circu~t
(Lean Exhaust lnd~cated) ............. A-54
Code 45
. Oxygen Sensor Circuit
(Rich Exhaust Indicated)
.............. A-56
Code 54
. Fuel Pump C~rcuit (Lowvoltage) . . 14-58
. ................... Code 51 MEM-CAL A-60
Code 52
. CALPAK Error
.......... (Faulty or Incorrect CALPAK) A-60
. ........... Code 53 System Over Voltage A-60

6E3-6 2.8L (VIN S). 5.OL (&BIN F) & 5.7L (WIN 8) BRllVEABlhlPY AND EMISSIONS
......... Fuel Pump Electrical Circuit C2-5
DIAGNOSiS ......................... CZ-5
.............. FUEL CONTROL SYSTERA C2.5
............ IDLE AIR CONTROLVALVE CZ-5
......... FUEL SYSTEM PRESSURE TEST C2-5
ON-CAR SERVICE ..................... C2-5
PORT FUEL INJECTION COMPONENTS .... Cf-5
FUEL PRESSURE RELIEF PROCEDURE ..... C2-5
Plenum ......................... C2-5
................ FUEL RAILASSEMBLY CP-6
FUEL RAIL SERVICE ................... C2-7
................... IDENTIFICATION C2-7
........... UNIT SERVICE PROCEDURES C2-7
COLD START .TUBE & VALVE ASSEMBLY ... ~2-7
PARTS INFORMATION ............... CZ-9
.... FUEL PRE5Si.J RE COPdNECl'ION ASSY C2-10
FUEL INJECTORS (Rail Removed) ........ C2-10
PRESSURE REGULATOR (Ball Removed) ... C2-10
COLD START FUEL INJEClION SWITCH ... C2-1%
THROTTLE BODY ................... CZ-11
VWROTTLE BODY SERVICE IDENTIFICATION . C2-12
............ UNIT REPAIR PROCEDURES Cf-112
TPS Adjcistment .............. C2-12
MiNIRilUM IDLE SPEED CHECK ........... CE-'I2
................. PARTS INFORMATION C2-15
IDLE AIR C'NT' L VALVE ASSY (3r: GASKET . . C2-15
CLEAN AIR COVER & GASKET .......... C2-15
SECTION C4 . 5.0h (VIN F) & 5.7L (VIN 8)
lGNITlON SYSTEMIEST
................ GENERAL DESCRIPTION C4-1
......................... PURPOSE C4-1
OPERATION ....................... C4-1
RESULTS OF INCORRECT OPERATION .... C4-1
......................... DIAGNOSIS C4-1
CODE 12 .......................... C4-1
ON-CAR SERVICE ..................... C4-2
SETTING TIMING .................... C4-2
HOW CODE 42 IS DETERMINED ......... C4-2
................. PARTS INFORMATION C4-2
lgn~tion System Check
Chart C-4
......................... C4-4
SECTION C5 . 5.0L (VIM F) & 5.7L JVIN 8)
ELECTRONIC SPARK CONTROL (ESC) SYSTEM
................ GENERAL DESCRIPTION C5-1
......................... PURPOSE C5-1
.............. GENERAL DESCRIPTION C5-1
......................... DlAGNOSiS C5-1
..................... ON-CAR SERVICE C5-1
....................... ESCSENSOR 65-1
.......... E4C MODULE AiYD BRACKET 165-2
................. PARTS INFORMATXBM C5-2
Electronic Spark Control
Chiirt C-5 ......................... C5-4
IDLE AIR CBi\~TROVCOOLANl'CVR . AS57 0
Throlrle Body Reinovecl Froti.1 Engine . .
FUEL PUlVlP RELAY ..................
................ OIL PRESSURE 5WETCI-I
P/%RVS INFORMATION .................
Irilector Halarlce Test
Chart
C-2A ........................
Idle Air Control
Chart
C-%C ........................
C2-I 5 SECYlOM Ct; . 5.0L (VlN F) & 5.7L (VIN 8)
62-1 5 A8W INJECTION REACTION (A.I.R.) SYSTEM
C2-16 GENERAL DESCRbPTION ............... CG-I
C2-16 PURPOSE ....................... C6-1
C2-76 OPE RATION ...................... C6-1
AIR COPJTROL PEDES VALVE ......... C6-I
C2-'18 RESULTS OF INCORRECT OPERATION .... C6-2
DIAGNOSIS ........................ C6-2
............. Cf -20 OPERATIONAL CHECKS C6-2
SbCTIBN C3 . 5.0L (VIN F) h 5.7L (V1N 8)
I:itAPORAIIVE EMISSlON CONTROL (EECS) SYSTEM
LZNERA. L DESCRIP'rION ............... C3-'!
PURPOSE ........................ C3-1
VAPOR CANISTER
.............. $3-1
EVAF'OFt/?ITIVE EMISSION SYSTEM .me.e. C3-4
FUEL TANK PRESSURE CONTROL VALVE . . C3-2
IN-'TANK PRESSURE CONTROL VALVE . . 63-2
RESULTS OF IRiCORRECT OPERATIGN .... C3-2
DIAGNOSIS ........................ C3-2
VISUAL CHECK OF CANIS'rkR .......... C3-2
FUNCPIONAL TEST
Vapor
Can~saer Purge Valve ........ C3-9
Tank Pressure Control Valve ..... C3-2
ON-CAR SERVICE ................. C3-3
FUEL VAPOR CANISTER ............ C3-3
CANISTER HOSES.
................... C3-3
PARTS INFORiblAT%BN ................ C3-3
Canister Purge Valve Check
Chart
C-3 ......................... C3-4
...................... Air Pump C6-2
................. Hoses and Pipes C6-3
.................... Check \/alve C6-3
.................... ON-CAR SERVICE C6-3
...................... DRIVE BELT C6-3
AIR INJECTION PUMP ............... C6-3
AIR INJECTION CONTROL
.................. (PEDES) VALVE C6-3
AIR ~NJECTION CIIECK VALVE ......... ~6-4
................ PARTS INFORMATION C6-4
AIR Management Check (PEDES)
........................ Chart C-6 C6-6
SECTlON C7 . 5.OL (VlN F) & 5.7L (VIN 8)
EXHAUST GAS RECIRCULATION {EGR) SYSTEM
GENERAL DESCRIPI'ION ..............*. C7-1
......................... PURPOSE C7-I
OPERATION
....................... C7-1
EGR
CONTROL .................... C7-1
NEGATIVE BACKPRESSURE EGR VALVE . . C7-2
EGR \/ALVE IDEhITIFICATION ........... C7-2

DRIVEABILITY AND EMISSIONS f.8b (VIN S) 6E3-A-1
Cold Oxygen Sensor
The "Diagnostic Circuit Check" verifies the On some engines.
the oxygen sensor will cool off
system is functioning correctly . some special after only a short period of operation at idle . This will
considerations to keep in mind while making the put the system into "Open Loop" . To restore "Closed
"Diagnostic Circuit Check" are: Loop"
operation. run the engine
at part throttle
several minutes and accelerate from idle to part
Blocking Drive Wheels throttle a few times .
The vehicle drive wheels should always be blocked Basic Procedure
while checking the system . If you have not reviewed the basic information on
how to
use the diagnostic procedures. go to the
introduction of this section
.
ENGINE COMPONENTS /WIRING DIAGRAMS / DIAGNOSTIC CHARTS
ComponentLocations ........................................................ PageA-2
Wiring Diagrams (1 of 3) ...................................................... Page A.3.4. 5
ECM Connector Terminal End View
.............................................. Page A-6
Diagnostic Circuit Check
...................................................... Page A-8
No "Service Engine Soon" bight
. Chart A-1 ........................................ Page A-10
No
ALBL or Won't Flash Code 12 . "Serv~ce Engine Soon" Light On Steady . Chart A-2 ........ Page A-12
. Engine Cranks But Won't Run Chart A-3 (1 of 2) .................................... Page 8-14
. Fuel System Diagnosis Chart A-7 (1 of
2) .......................................... Page A-18
Cold Start Valve
. Chart A-9 .................................................... Page A-22
Code 13 Oxygen Sensor Circuit (Open Circuit)
...................................... Page A-24
Code 14 Coolant Temperature Sensor Circuit (High Temp
. Indicated) ..................... Page A-26
Code 15 Coolant Temperature Sensor Circuit (Low Temp
. Indicated) ..................... Page A-28
Code 21 Throttle Position Sensor (TPS) Circuit (Signal Voltage High)
...................... Page A-30
Code 22 Throttle Position Sensor (TPS) Circuit (Signal Voltage Low)
...................... Page A-32
Code 23 Manifold Air Temperature (MAT) Sensor Circuit (Low Temp
. Indicated) ............ Page A-34
Code 24 Vehicle Speed Sensor (VSS) Circuit
........................................ Page A-36
Code
25 Manifold Air Temperature (MAT) Sensor Circuit (High Temp . Indicated) ............ Page A-38
Code 32
EGR System Failure .................................................... Page A-40
Code 33 Mass Air Flow (MAF) Sensor Circuit
(GMISEC High) ............................. Page A-42
Code 34 Mass Air Flow (MAF) Sensor Circuit
(GMISEC bow) ............................. Page 8-44
Code
41 Cylinder Select Error .................................................. Page A-46
Code 42 Electronic Spark Timing Fault
................... .... .................... Page 8-48
Code 44 Oxygen Sensor Circuit (Lean Exhaust Indicated)
.............................. Page A-50
Code
45 Oxygen Sensor Circuit (Rich Exhaust Indicated) ............................... Page A-52
Code 54 Fuel Pump Circuit
(Lowvoltage) .......................................... Page A-54
Code
51 PROM Error (Faulty or Incorrect PROM) ..................................... Page A-56
Code 52 CALPAK Error (Faulty or Incorrect CALPAK)
................................. Page 44-56
Code 53 System Over Voltage .................................................. Page A-56
Code55ECMError ............................O.~o.~.~e.~e~e.~e....... .. PageA-56

6E3-A-2 2.88, (VIM S) DRIVEABILITY AND EMISSIONS
'Fa SERIES
COMPUTER HARNESS
C1 Electronic Control Module (ECM)
C2 ALDL diagnostic connector
C3 "SERVICE ENGINE
SOON" light
C4 ECM powerlfuel pump fuse
C5 ECM harness ground
C6 Fuse panel
C8 Fuel pump test connector
(ALDL"G")
C9 MAFfuse
CONTROLLED DEVICES
1 Fuel injector
2
Idle air control motor
3 Fuel pump relay
5 Trans. Conv. Clutch connector
6a Remote ignition coil
8 Engine coolant fan relay
9 Air control solenoid (M.T. only)
12 Exhaust Gas Recirculation solenoid
0 INFORMATION SENSORS
B Exhaust oxygen
C Throttle position D Coolant temperature
F Vehicle speed
K Mass Air Flow
S Power steering pressure switch
T Manifold Air Temperature
U AIC pressure fan switch
13 AIC compressor relay
,..,a :'"' NOT ECM 'ONNECTED 15 Fuel vapor canister solenoid N1 Crankcase vent valve (PCV) 17 bass air flow sensor relay N4 Engine temp. switch (telltale)
N5 Engine temp. sensor (gage) Exhaust Gas Recirculation valve
N6 Oil press. switch (telltale)
N7 Oil press, sensor (gage)
N8 Oil press. swich (fuel pump)
N10 Cold start fuel injection switch
N11 Cold start valve 7-29-87 N12 Deceleration Valve (MIT only)
N13 Fan Override Switch *5S 2127-6E
Figure Al-l - Component Locations 2.8L "F" Series

6E3-A-4 2.8L (VIN S) DRIVEABILITY AND EMISSIONS
ECMIIGN
I I
I
1
I
I
I I
I
PRIMARY COIL I
I
I
I
I
FUEL PUMP
CONNECTOR FUEL
FUEL PUMP SIGNAL