Page 1089 of 1640
(From page 11 -44)
Inspect the IG COIL (30 A) fuse
in the engine compartment
fuse/relay box.
Is the fuse OK?
Turn the ignition switch ON.
Disconnect the 3P connector of
each sensor one at a time: MAP sensor
EGR
valve
lift
sensor
Accelerator pedal angle sensor
Does the MIL remain ON?
Connect the service check con-
nector terminals with a jumper
wire.
Disconnect the 3P connector of
each sensor one at a time:
TP sensor
Ignition timing adjuster
Does the MIL indicate
code 7 or 18?
Turn the ignition switch OFF.
Remove the jumper wire from the
service check connector.
Connect the test harness.
Disconnect the "D" connector
from the ECM only, not the engine
wire harness (see page 11-37).
Check for continuity between
body ground and the following
terminals: D19, D20.
(To page 11-46) Replace the fuse.
Substitute a known-good ECM
and recheck. If symptom/indica-
tion goes away, replace the origi-
nal
ECM.
Replace the sensor that caused
the light to go out upon its discon- nection.
Replace the TP sensor or ignition
timing adjuster. (From page 11-44)
Turn the ignition switch
OFF.
Disconnect "A" con-
nector from the ECM.
Turn the ignition switch
ON.
Is the MIL on?
Repair short to body
ground in BLU wire be-
tween the ECM (A13)
and
MIL.
Continuity?
(cont'd)ProCarManuals.com
Page 1090 of 1640
PGM-FI System
Troubleshooting Flowchart Engine Control Module (ECM) (cont'd)
(From page 11-45)
Is there continuity?
Reconnect all the connectors. Reconnect the "D" connector to
the
ECM.
Turn the ignition switch ON.
Measure voltage between body
ground and the following termi-
nals individually:
A26,
B2.
Is there less than 1.0 V?
Measure voltage between A26
(-) and the following: C1 (+) and
A25 ( + ).
Is there battery voltage?
Substitute a known-good ECM
and recheck. If symptom/indica-
tion goes away, replace the origi-
nal
ECM. Repair short to body ground in
YEL/WHT wire between ECM
(D19) and MAP sensor.
Repair short to body ground in
YEL/WHT wire between ECM
(O20) and TP sensor. EGR
valve life sensor, ignition tim-
ing adjuster or accelerator pe-
dal angle sensor.
Repair open in BRN/BLK (A26) or
BRN/WHT (B2) and G101 (locat-
ed at right middle of engine).
Repair open in YEL/BLK wire
between ECM (A25. CD and
PGM-FI main relay.
Check PGM-FI main relay and
wiring connectors at PGM-FI
main relay.ProCarManuals.com
Page 1092 of 1640
System Description
The idle speed of the engine is controlled by the Idle Air Control (IAC) valve.
The valve changes the amount of air bypassing into the intake manifold in response to electric current controlled by the
ECM.
When the IAC valve is activated, the valve opens to maintain the proper idle speed.
(cont'd)
IDLE
ADJUSTING
SCREW
FAST
IDLE
THERMO
VALVE
IAC VALVE
TO PGM-FI MAIN
RELAY
YEL/BLK
BLU/REDProCarManuals.com
Page 1095 of 1640
Idle Control System
Troubleshooting Flowchart
Air Conditioning Signal
This signals the ECM when there is a demand for cooling from the air conditioning system.
Inspection of Air Condition-
ing Signal.
Connect the test harness be-
tween the ECM and connector. Disconnect "C" connector from
the engine wire harness only, not
the ECM (see page 11-37).
Turn the ignition switch ON.
Measure voltage between C3 (+)
terminal and A26 (-) terminal.
Is there approx. 10 V?
Turn the ignition switch OFF.
Reconnect "C" connector to the
engine wire harness.
Turn the ignition switch ON.
Momentarily connect A15 ter-
minal to A26 terminal several
times.
Is there a clicking noise from the
A/C compressor clutch?
Start the engine.
Blower switch ON.
(To page 11-91) Repair open in RED/BLU wire be-
tween ECM (A15) and A/C
clutch relay. Is there a clicking noise from the
A/C compressor clutch?
Connect the RED/BLU terminal of
the 4P connector on the A/C
clutch relay to body ground. View from relay side
(sub relay box A)
RED/BLU
See air conditioner in-
spection (see section
22).
Substitute a known-
good ECM and re-
check. If prescribed
voltage is now avail-
able, replace the ori-
ginal ECM.ProCarManuals.com
Page 1107 of 1640
6. Turn the ignition switch OFF.
7. Reconnect the 2P connector on the IAC valve, then
remove CLOCK fuse in the under-hood fuse/relay
box for 10 seconds to reset ECM.
8. Restart and idle the engine with no-load conditions
in which the headlights, blower fan, rear defogger,
cooling fan, and air conditioner are not operating
for one minute, then check the idle speed.
Idle speed should be:
M/T
A/T
800
50 rpm
750
50 rpm
(in or range)ProCarManuals.com
Page 1108 of 1640
Fuel Supply System
System Troubleshooting Guide
NOTE: Across each row in the chart, the sub-systems that could be sources of a symptom are ranked in the order they should be inspected starting with . Find the symptom in the left column, read across to the most likely source, then
refer to the page listed at the top of that column. If inspection shows the system is OK, try the next most likely system
,
etc.
PAGE
SUB-SYSTEM
FUEL
INJECTOR FUEL
INJECTOR
RESISTOR
FUEL
PRESSURE
REGULATOR
FUEL
FILTER
FUEL
PUMP PGM-FI
MAIN
RELAY
FUEL PUMP
RELAY
FUEL PUMP
RESISTOR
CONTAMI-
NATED FUEL
SYMPTOM
ENGINE WON'T START
DIFFICULT TO START ENGINE
WHEN COLD OR HOT ROUGH IDLE
107
112
113
114
115
120
116,
124
POOR
PERFORMANCE
MISFIRE OR
ROUGH
RUNNING
FAILS
EMISSION
TEST
LOSS OF
POWERProCarManuals.com
Page 1109 of 1640
System Description
The fuel supply system consists of a fuel tank, in-tank high pressure fuel pump, fuel pump relay, fuel pump
resistor, PGM-FI main relay, fuel filter, fuel pressureregulator, fuel injectors and fuel injector resistor.
This system delivers pressure-regulated fuel to the fuel injectors and cuts the fuel delivery when the engine is
not running. Fuel Pressure
Relieving
Do not smoke while working on the fuel system.
Keep open flames or sparks away from your work
area.
Be sure to relieve fuel pressure while the engine is
off.
NOTE: Before disconnecting fuel pipes or hoses,
release pressure from the system by loosening the 6
mm service bolt at top of the fuel filter. 1. Disconnect the battery negative cable from the battery negative terminal.
2.
Remove
fuel
fill
cap.
3. Use a box end wrench on the 6 mm service bolt at the fuel filter, while holding the special banjo boltwith another wrench.
4. Place a rag or shop towel over the 6 mm service bolt.
5. Slowly loosen the 6 mm service bolt one complete turn.
SERVICE BOLT
12 N .
m (1.2 kg-m, 9lb-ft)
SHOP
TOWEL
FUEL FILTER
NOTE:
A fuel pressure gauge can be attached at the 6 mm
service bolt hole.
Always replace the washer between the service bolt
and the special banjo bolt, whenever the service
bolt is loosened to relieve fuel pressure.
Replace all washers whenever the bolts are
removed to disassemble parts.
(cont'd)ProCarManuals.com
Page 1113 of 1640
Fuel Supply System
Fuel Injector Resistor
Description
The fuel injector resistor lowers the current supplied to
the fuel injectors to prevent damage to the fuel injector
coils. This allows a faster response time of the fuel
injectors.
ECM
PGM-FI
MAIN
RELAY
Testing
1. Disconnect the fuel injector resistor connector.
2. Check for resistance between each of the fuel in-
jector resistor terminals (B, C, D, F, G and H) and
the power terminal (E).
Resistance should be: 5—7
FUEL
INJECTOR
RESISTOR
B
C
D
F
G
H
E
Replace the fuel injector resistor with a new one
if any of the resistances are outside of the
specification.
FUEL
INJECTOR RESISTOR
FUEL
INJECTORSProCarManuals.com
