PONTIAC FIERO 1988 Service Repair Manual

6E2-6 5.OL (VIN E) DRIVEABILITY AND EMISSIONS
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DRIVEABILITY AND EMISSIONS S.OL (VIN E) 6EZ-A-1
5.OL ENGINE
DIAGNOS"FC CIRCUIT CHECK 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
.
SECTION A
ENGINE COMPONENTS
/ WlRlNG DIAGRAMS 1 DIAGNOSTIC CHARTS
Component Locations ........................................................ Page A-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" Light. Chart A-1 ......................................... Page 14-10
No ALDL Data or Won't Flash Code 12. "Service Engine Soon" Light "ON" Steady. Chart A-2 ... Page A-I 2
Engine Cranks But Will Not Run . Chart A-3 (1 of 2) .................................. Page A-1 4
. Fuel System Diagnosis Chart A-7 (1 of 2) .......................................... Page A-1 8
Code 13 Oxygen Sensor Circuit (Open C~rcu~t) ...................................... Page A-22
Code 14 Coolant Temperature Sensor Circu~t (HighTemperature Indicated) ............... Page A-24
Code 15 Coolant Temperature Sensor Circu~t (LowTemperature Indicated) ............... Page A-26
Code 21 Throttle Position Sensor (TPS) Circu~t (S~gnal Voltage High) ...................... Page A-28
Code 22 Throttle Position Sensor (TPS) Circuit (Signal voltage Low) ..................... Page A-30
Code 23 Manifold Air Temperature (MAT) Sensor Circuit (Low Temp . Indicated) ............ Page A-32
Code 24 Vehicle Speed Sensor (VSS) Circuit ........................................ Page A-34
Code 25 Manifold Air Temperature (MAT) Sensor Circuit (High Temp . Indicated) ............ Page A-36
Code 32 Exhaust Gas Recirculation (EGR) Circuit .................................... Page A-38
Code 33 Manifold Absolute Pressure (MAP) Sensor Circuit (Signal Voltage High-Low Vacuum) . . Page A-40
Code 34 Manifold Absolute Pressure (MAP) Sensor Circuit (Signal Voltage Low-High Vacuum) . . Page A-42
Code 42 Electronic Spark Timing (EST) Circuit ...................................... Page A-44
Code 43 Electronic Spark Control (ESC) Circuit ...................................... Page A-46
Code 44 Oxygen Sensor Circuit (Lean Exhaust Indicated) .............................. Page A-48
Code 45 Oxygen Sensor Circuit (Rich Exhaust Indicated) .............................. Page A-50
Code 53 Vehicle Anti-Theft System (VATS) Circuit ................................... Page A-52
Code 54 Fuel Pump Circuit (Low Voltage) ......................................... Page A-54
Code 51 Code 51 PROM Error .................................................. Page A-56
Code 52 Calpak Error (Faulty or Incorrect Calpak) ................................... Page A-56
.......................................................... Code55ECMError PageA-56

6E2-A-2 5.OL (VIN E) DRIVEABILIW AND EMISSIONS
IFf SERIES VIN CODE: E
OCOMPUTER HARNESS
C1 Electronic Control Module
C2 ALDL diagnostic connector
C3 "SERVICE ENGINE SOON" light
C5 ECM harness grounds
C6 Fuse panel
C8 Fuel pump test connector
C9 Fuel pump fuse & ECM power
C10 Set timing connector
....,
: . ... 'NOT ECM CONNECTED
N1 Crankcase vent valve (PCV)
N4 PIS Switch
N8 Oil pressure switch
[7 CONTROLLED DEVICES 0 INFORMATION SENSORS
1 Fuel injectors A Manifold Absolute Pressure
2 Idle air control motor B Exhaust oxygen
3 Fuel pump relay
C Throttle position
5 Trans. Conv. Clutch connector
D Coolant temperature
6 EST distributor
F Vehicle speed
6a Remote ignition coil
J ESCknock
7 Electronic Spark Control module MAT (on air cleaner)
9 Air injection port solenoid
10 Air injection converter solenoid
12 Exh. Gas Recirc. vacuum solenoid
15 Fuel vapor canister solenoid
Exhaust Gas Recirculation valve
6-1
0-87
Figure A-I - Component Locations 5.OL (VIN E)

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6E2-A-4 5.OL (VIN E) DRIVEABILITY AND EMISSIONS
SERVICE ENGINE
24PIN A-B CONNECTOR
SHIFTLITE __
* 8s 4455-6E - ~igure A-3 - ECM Wiring Diagram 5.OL (VIN E) (2 of 3)

DRIVEABILITY AND EMISSIONS 5.OL (VIN E) 6E2-A-5
IGN CONNECTOR - PN WBLK 39

6E2-A-6 5.8% (VIN E) DRIVEABILITY AND EMISSIONS
FUEL INJECTION ECM CONNECTOR IDENTIFICA"F0N
This ECM voltage chart is for use with a digital voltmeter to further aid in diagnosis. The voltages
you get may vary due to low battery charge
or other reasons, but they should be very close.
THE FOLLOWING CONDITIONS MUST
BE MET BEFORE TESTING:
@ Engine at operating temperature e Engine idling in closed loop (for "Engine Run" column)
r Test terminal not grounded e ALDL tool not installed
VOLTAGE
I
B + 1 B + I EGRCONTROLSOLI A4 I GRY
I I "SERVICE ENGINE I
1 1 1 A.I.R. DIVERT I I BLW I
o 10 1 4 TH GEAR I c7 ILT BLU
4.75 1.1 MAP SIGNAL C11 LT GRN
24 PIN A-B CONNECTOR
32 PIN C-D CONNECTOR
( 012 I NOT USED I I
BLW WHT Dl SYSTEMGROUND 0
PPL I D2 I MAPGROUND 10 10 I
BLK I D5 I BYPASS
D9 NOT USED I I I I Dl0 I NOT USED I I I
I Dl1 I NOT USED I I
LT GRN I DI~ I INJECTOR B l e+ IB+
Dl5 NOTUSED
LT BLU Dl6 INJECTORA B+ B+
1 Var~es from 60 to battery voltage, 6 Reads battery voltage in gear
depending
on positlon of drive wheels 7 12 volts, when englne IS crank~ng
2 12 V for f~rst two seconds.
3 Varies
4 12V when fuel pump is running
5 Var~es with temperature
ENGINE 5.0 L
Figure A-5 - ECM Connector Terminal End View 5.OL (VIN E)

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6E2-A-8 S.OL (VIN E) DRIVEABILITY AND EMISSIONS
DIAGNOSmIC CIRCUIT CHECK
The Diagnostic Circuit Check is an organized approach to identifying a problem created by an electronic
engine control system malfunction. It must be the starting point for any driveability complaint diagnosis,
because it directs the service technician to the next logical step in diagnosing the complaint.
The "Scan Data" listed in the table may be used for comparison, after completing the diagnostic circuit check
and finding the on-board diagnostics functioning properly and no trouble codes displayed. The "Typical Values"
are an average of display values recorded from normally operating vehicles and are intended to represent what a
normally functioning system would typically display.
A "SCAN" TOOL THAT DISPLAYS FAULTY DATA SHOULD NOT BE USED, AND THE PROBLEM
SHOULD BE REPORTED TO THE MANUFACTURER. THE USE OF A FAULTY "SCAN" CAN RESULT
IN MISDIAGNOSIS AND UNNECESSARY PARTS REPLACEMENT.
Only the parameters listed below are used in this manual for diagnosis. If
a "Scan" tool reads other
parameters, the values are not recommended by General Motors for use in diagnosis. For more description on the
values and use of the "Scan" to diagnosis ECM inputs, refer to the applicable diagnosis section in Section
"C". If
all values are within the range illustrated, refer to "Symptoms" in Section
"B".
""SCAN" DATA
Idle / Upper Radiator Hose Hot / Closed Throttle / Park or Neutral /Closed Loop / Acc. off
"SCAN" Position Units Displayed Typical
Data Value
Coolant Temp. CO 85" - 105"
TPS Volts .4 - 1.25
MAP Volts
1 - 2 (depends on Vac. & Baro pressure)
INT (Integrator) Counts Varies
BLM (Block Learn) Counts 118- 138
IAC Counts (steps) 1-50
RPM RPM 1000
k 75 RPM (depends on temperature)
0 2 Volts .001 - 999 and varies
OpenIClosed Loop OpenICIosed Closed Loop (may go open with extended idle)
A/C Request YesINo No (yes, with A/C requested)
PIN Switch PIN and RDL
ParkINeutral (PIN)
TCC
On/Off Off1 (on, with TCC commanded)
VSS MPH 0
Battery Volts 13.5- 14.5
Air Switch NormalIDivert Normal
Air Divert ConverterIPort Converter
Knock Signal
YesINo N o
4th Gear
YesINo No (Yes, if in 4th Gear)
MAT Temp.
CO 10" - 90" ( Depends on Under Hood Temp.).
Power Steering Pressure Switch
NormalIHi Pressure Normal

DRIVEABILITY AND EMISSIONS 5.OL (VIN E) 6EZ-A-9
I SEE CHART A-2 4- ---------- 2