1991 FORD FESTIVA service

Fig. 1: Testing Canister Purge Solenoid

Courtesy of FORD MOTOR CO.
Carbon Canister
1. Start and run engine until it is at operating temperature. Stop engine. Remove carbon canister. Carbon canister on 1.3L is located under
brake booster. Carbon canister is located in right side of engine compartment near cowl panel on 1.6L.
2. Inspect carbon canister for presence of liquid fuel, as evidenced by odor or weight. Blow into air vent and ensure air exits fro m fu el
vapor inlet. Replace carbon canister if it contains fuel, or if air does not pass freely through it.
POSITIVE CRANKCASE VENTILATION (PCV)
1. Remove PCV valve from valve cover and disconnect it from PCV h o se . S h a ke va l ve vigo r o u sl y t o e n su r e p l u n ge r is fr e e t o mo ve .
Replace PCV valve if plunger is not free.
2. Idle engine until it is warm. Remove fresh air hose at inlet end. Plug nipple immediately to prevent stalling. Verify presence of vacuum at
inlet end of hose. If vacuum is not present, replace PCV valve or service hoses or loose oil dipstick.
THROTTLE CONTROLS
Dashpot
Disconnect PCV valve. Remove resonance chamber. Push dashpot rod in and then release it. Replace dashpot if rod does not go in slowly and
return quickly.
MISCELLANEOUS CONTROLS
A/C CLUTCH
A/C Clutch Relay
Remove relay from its socket near left headlight, in front of battery. Connect ohmmeter to contact terminals (Blue/Red and Black/White wires
on mating connector). Ohmmeter should indicate continuity. Supply 12 volts to remaining terminals (Green/Yellow and Yellow wires on
mating connector). Ohmmeter should indicate no continuity.
COOLING FAN
Cooling Fan
Unplug connector from cooling fan. Apply 12 volts to one terminal of fan connector. Ground remaining fan connector terminal. Replace fan if
it does not run.
Cooling Fan Control Relay
Remove relay from its socket near left headlight. Connect ohmmeter to contact terminals. Wire colors are Yellow/Red and Black on mating
connector on Festiva; Yellow/Green and Black on Capri. Ohmmeter should indicate continuity. Supply 12 volts to remaining 2 relay
terminals. Ohmmeter should indicate no continuity.
NOTE:Although som e of the controlled devices listed here are not technically engine perform ance
com ponents, they can affect driveability if they m alfunction.
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memory. Intermittent failures may be caused by a sensor, connector, or wiring. See INTERMITTENTS in TESTS W/O CODES article in the
ENGINE PERFORMANCE Section.
VISUAL CHECK & VEHICLE PREPARATION
Before connecting any equipment to diagnose EEC system, perform following preparatory procedures:
Verify condition of air cleaner and air ducts.
Check all vacuum hoses for leaks, restrictions, or improper routing.
Check EEC system wiring harness electrical connections for corrosion, bent or broken pins, loose wires or terminals, or improper
routing.
Check ECA, sensors, and actuators for physical damage.
Check engine oil and coolant level.
Perform all necessary safety precautions to prevent personal injury or vehicle damage.
Set parking brake. Place shift lever in Park for automatic transmissions, or Neutral for manual transmissions. DO NOT move shift lever
during test unless specifically directed.
Turn off all lights and accessories. Ensure vehicle doors are closed when measuring voltage or resistance.
Start engine. Run at idle until upper radiator hose is hot and pressurized and engine is off fast idle. Check for leaks around exhaust
manifold, exhaust gas oxygen sensor, and vacuum hose connections.
Turn ignition off. Service items as required. Go to EQUIPMENT HOOK-UP .
EQUIPMENT HOOK-UP
VOM
1. Turn ignition off. Connect a jumper wire from STI connector to ground. Refer to SELF-TEST CONNECTOR LOCATION and
SELF
-TEST CONNECTOR WIRE COLORS tables. See Fig. 1 .
2. Connect VOM between STO terminal and engine ground. Set VOM to measure 0-20 volts DC.
CHECK ENGINE Light (MIL)
Connect a jumper wire between STI connector and ground.
SUPER STAR II Tester
Turn ignition off. Connect adapter cable leads to diagnostic tester. Connect service adapter cables to vehicle self-test connectors. Ground
adapter cable.
SELF-TEST CONNECTOR LOCATION
SELF-TEST CONNECTOR WIRE COLORS

Fig. 1: Self
-Test Connector Terminal ID
Courtesy of FORD MOTOR CO.
RETRIEVING CODES
Reading Service Codes
ApplicationLocation
1.3LLeft Rear Corner Of Engine Compartment
1.6LRight Rear Corner Of Engine Compartment
CircuitWire Color
1.3L
SMLBlue/Green
STIYellow/Green
STOYellow/White
1.6L
SMLBlack/Blue
STIYellow
STOGreen/Black
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Engine control system communicates malfunctions to technician through service codes. These service codes are 2-digit numbers representing a
particular defect. Service codes are transmitted through STO connector.
Service codes are displayed as timed pulses, and may be read with a VOM or Super Star II tester. VOM displays codes by needle sweeps. See
Fig. 2
.
Turn ignition off. Ensure all procedures of EQUIPMENT HOOK
-UP have been followed. Engine should be at normal operating
temperature.

Fig. 2: Reading Service Codes With VOM

Courtesy of FORD MOTOR CO.
VOM
Disconnect and reconnect jumper wire from STI terminal to ground. Turn ignition on. Record displayed codes. Erase codes, and repeat test
procedure to verify all codes are currently valid. See ERASING CODES & RETESTING . Service only those codes which appear during
retest. Refer to TROUBLE CODE DEFINITION
table to find appropriate pinpoint test.
MIL
Turn ignition on. Connect a jumper wire between STI connector and ground. Observe MIL, and record pulses to determine codes stored.
SUPER STAR II Tester
Set center button to TEST position. Turn ignition on. Turn tester on. When activated, tester should display 888 for 2 seconds. Release and
reset center TEST button. After all codes are displayed, release center button. All codes in tester memory may now be reviewed.
ERASING CODES & RETESTING
Erasing codes and retesting will give an indication of whether codes are hard or intermittent defects. Hard codes reset immediately and will be
displayed during retest.
Disconnect negative battery cable. Press brake pedal for 5-10 seconds. Turn off VOM or Super Star II tester. Reconnect battery. Perform tests
under RETRIEVING CODES
to again display and record codes.
TROUBLE CODE DEFINITION
TROUBLE CODE DEFINITION
NOTE:If MIL flashes continuously prior to connecting test equipm ent, go to PINPOINT T EST ST I .
Service CodeFaultCircuit & Pinpoint Test
01Ignition Diagnostic MonitorIDM
02 (1) Crankshaft Position SensorCPS
03 (2) Cylinder Identification SensorCID
06 (2) Vehicle Speed SensorVSS
08Vane Airflow MeterVAF
09Engine Coolant Temperature SensorECT
10Vane Air Temperature SensorVAT
12 (2) Throttle Position SensorTP
14Barometric Pressure SensorBP
15Exhaust Gas Oxygen SensorEGO
17Exhaust Gas Oxygen SensorEGO
25 (2) Fuel Pressure Regulator Control SolenoidPRC
26Canister Purge Control SolenoidCANP
34Idle Speed ControlISC
Codes Not ListedPower & Ground ConnectionsPGC
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CLEARING CODES
Clearing Codes Procedure
Disconnect negative battery cable. Press brake pedal for 5-10 seconds. Turn off VOM or Super Star II tester. Reconnect battery.
ECA LOCATION
ECA is located on center console behind kick panel on Capri, and under instrument panel on driver side of Festiva.
QUICK TESTS
KEY ON, ENGINE OFF (KOEO) SELF-TEST
KOEO
1. This is a test of electronic engine control system, conducted with power (voltage) applied and engine not running. Activate self-test, and
record all codes displayed.
2. Erase codes, and repeat self-test. Diagnose only codes occurring during repeat self-test. See TROUBLE CODE DEFINITION
table. If
no codes are present, proceed to KEY ON, ENGINE RUNNING (KOER) SELF
-TEST .
KEY ON, ENGINE RUNNING (KOER) SELF-TEST
KOER
1. Deactivate self-test. Start and run engine at 2000 RPM for 2 minutes to warm up EGO sensor. Turn off engine and wait 10 seconds.
2. Restart engine, and activate self-test. Record all service codes displayed. See TROUBLE CODE DEFINITION
table. If no codes are
present, proceed to SWITCH MONITOR TEST
.
SWITCH MONITOR TEST
This test procedure checks input signals received by ECA from individual switches. Use following procedure to perform switch monitor test:
Turn engine off and allow it to cool.
Ensure all accessories are turned off.
Deactivate self-test.
Ensure transmission is in Neutral or Park.
Turn ignition on.
SUPER STAR II Tester
Connect Super Star II tester adapter cable. Turn on tester. Latch center button. Operate each switch listed in SWITCH MONITOR TEST
table. Note output of LED on adapter cable as each switch operates. Record test results.
VOM
1. Ground STI connector. Connect VOM positive lead to SML terminal on self-test connector. Connect negative lead to ground. See Fig.
1 .
2. Operate each switch listed in SWITCH MONITOR TEST
table. Note output on VOM as each switch is operated. Go to specified
PINPOINT TEST if any switch does not meet specification.
SWITCH MONITOR TEST
(1)Festiva only.
(2)Capri only.
NOTE:DO NOT m ove throttle during KOEO self-test.
NOTE:It is necessary to clear codes in m em ory before perform ing this test. DO NOT m ove throttle during test.
NOTE:All switches m ust be tested individually. Allowing a switch to rem ain on while testing another will lead
to false test results.
NOTE:DO NOT m ove throttle, clutch, or transm ission lever unless so directed.
SwitchVOM Indication/Condition(1) Pinpoint Test
A/C SwitchLess Than 1.5 Volts; A/C & Blower Switch OnSTG
Blower Motor SwitchLess Than 1.5 Volts; Switch Set To "2" Or HigherSTG
Brake On/Off SwitchLess Than 1.5 Volts; Brake Pedal Partially
PressedSTP
Clutch Engage/Neutral Gear Switch (2) Less Than 1.5 Volts; In Gear, Clutch ReleasedSTG
Coolant Temperature SwitchLess Than 1.5 Volts; Cooling Fan OnSTP
Defrost SwitchLess Than 1.5 Volts; Defrost Switch OnSTP
Headlight SwitchLess Than 1.5 Volts; Headlight Switch OnSTP
Id l e Swit chLess Than 1.5 Volts; Accelerator Pedal PressedSTG
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WIGGLE TEST
Checking Circuitry
1. Visually inspect suspected sensor, switch, or solenoid. Enter WIGGLE TEST if using Super Star II tester. If using VOM, connect it to
STO terminal on self-test connector, and ground STI self-test connector terminal. Lightly tap sensor, switch, or solenoid.
2. Push and pull on suspected sensor, switch, or solenoid connector, but DO NOT unplug it. Test and wiggle harness vigorously, working
in small sections, from suspected device toward dash panel, and from dash panel to ECA.
3. If VOM or Super Star II tester does not display a positive indication of an intermittent defect, carefully disconnect suspected device.
Remove terminals from connector.
4. Inspect terminals at both ends for corrosion, bad crimps, or improperly seated terminals. Reconnect after inspection. Unplug harness
fro m E CA.
5. Inspect ECA and harness connector terminals for corrosion, bad crimps, or improperly seated terminals. If VOM does not indicate any
intermittent defect, reconnect wiring and erase codes.
PINPOINT TESTS
HOW TO USE PINPOINT TESTS
1. DO NOT perform any PINPOINT TEST unless directed by a QUICK TESTS procedure. Ensure all non-EEC related defects are
corrected. Follow each test step in order until defect is found. DO NOT replace any part unless so directed. When more than one service
code exists, start with first code displayed.
2. PINPOINT TESTS require ensuring electrical circuits are okay before replacing sensors or any other components. Always test circuits
for continuity between sensor and ECA. Test all circuits for shorts to power, opens, or shorts to ground. VREF and VPWR circuits
should be tested with KOEO or as specified in PINPOINT TESTS.
3. DO NOT measure voltage or resistance at ECA, or connect any test light unless specified in testing procedure. DO NOT pierce wiring.
Isolate both ends of a circuit and turn key off whenever checking for shorts or continuity, unless otherwise specified.
4. Disconnect solenoids and switches before checking circuit continuity or energizing solenoids.
5. An open is defined as any resistance greater than 10,000 ohms, unless otherwise specified.
6. To help diagnose circuits to ECA, turn ignition off and disconnect ECA harness. Connect BOB between ECA and ECA harness to
perform circuit and pinpoint tests.
PINPOINT TEST IDM - IGNITION DIAGNOSTIC MONITOR

Fig. 3: Identifying IDM Circuit & Connector

IDM CIRCUIT PIN IDENTIFICATION
Manual Lever Position SwitchLess Than 1.5 Volts; Transaxle In Park Or NeutralSTP
Wide Open Throttle SwitchLess Than 1.5 Volts; Accelerator Pedal Fully
PressedSTG
(1)Proceed to PINPOINT TEST indicated if Super Star II tester/VOM indication is incorrect.
(2)Not applicable to vehicles with A/T.
NOTE:Following tests and illustrations are courtesy of Ford Motor Co. Com plete EEC system wiring diagram s
m ay be found in WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section.
NOTE:Check all wiring, harnesses, connectors, and com ponents for dam age, overheating, shorting, or
looseness. If any defect is found, repair as necessary before proceeding to any PINPOINT T EST .
NOTE:Enter this test only when Code 01 is displayed during QUICK T EST S procedure or when directed here
from another PINPOINT TEST.
CircuitECA PinBOB PinWire Color
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Fig. 6: Identifying KC Circuit & Connectors

1. Disconnect and plug vacuum hose at distributor. Connect timing light. Start engine. Unplug knock control service connector, located
near ECA. If timing retards, service knock sensor and/or knock sensor wiring. If timing does not retard, go to next step.
2. Determine and record ignition timing setting. Tap intake plenum with plastic mallet. If timing does not retard, go to step 4). If t imin g
retards, go to next step.
3. Reconnect knock control service connector, located near ECA. Determine and record ignition timing setting. Tap intake plenum with
plastic mallet. If timing does not retard, knock control unit is okay; go to next step. If timing retards, replace knock control unit.
4. Turn ignition off. Unplug knock control service connector, located near ECA. Install a known good knock sensor. Start engine. Tap
intake plenum with plastic mallet. If timing retards, replace knock sensor. If timing does not retard, go to next step.
5. Check VPWR and GND (Yellow/Green and Black/Yellow wires respectively) to knock control unit for shorts or open circuits. Service
wires as necessary. If wires are okay, replace knock control unit.
PINPOINT TEST VSS - VEHICLE SPEED SENSOR

Fig. 7: Identifying VSS Circuit & Connectors

VSS CIRCUIT PIN IDENTIFICATION
1.Install 4EAT Tester Leave 4EAT module disconnected. Disconnect speedometer cable at transaxle. Measure resistance between BOB
VSS and GND test pins. Rotate speedometer cable. If resistance drops to less than 5 ohms 4 times for each revolution of speedometer
cable, VSS is okay. Return to QUICK TESTS if sent here from there; otherwise, replace 4EAT module. If resistance does not drop as
NOTE:Enter this test only when Code 06 is displayed during QUICK T EST S procedure or when directed here
from another PINPOINT TEST.
Circuit4EAT PinWire Color
GND1JBLK
VSS1PGRN/RED
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connector to corresponding terminals on TP sensor connector. Turn ignition on. Measure voltage between TP and SIGRTN terminals on
TP sensor while opening throttle. Compare voltage to specification in TP SENSOR OUTPUT VOLTAGE
table. If voltage is within
specification, repair TP wire to ECA. Go to next step if voltage is not within specification.
3. Turn ignition off. Unplug TP harness connector. Turn ignition on. Measure voltage between VREF and SIGRTN wires on TP harness
connect-or. If voltage is 4-5 volts, replace TP sensor. If voltage is not 4.5-5.5 volts, go to next step.
4. Measure voltage between VREF wire on TP harness connector and ground. If voltage is 4-5 volts, adjust or replace throttle position
sensor. If voltage is not 4-5 volts, go to PINPOINT TEST VREF
.
PINPOINT TEST BP - BAROMETRIC PRESSURE SENSOR

Fig. 12: Identifying BP Sensor Circuits

1.3L
BP sensor is incorporated into ECA; it cannot be checked or serviced separately. If Code 14 is set and cannot be cleared, replace ECA.
1.6L
Turn ignition off. Connect BOB. Remove dust cover from BP sensor, located on passenger side cowl. Turn ignition on. Connect vacuum pump
to BP sensor. Measure voltage between pins BP and SIGRTN on BOB while applying vacuum to BP sensor. See BAROMETRIC
PRESSURE SENSOR OUTPUT VOLTAGE table. Replace BP sensor if voltage is not as specified.
BAROMETRIC PRESSURE SENSOR OUTPUT VOLTAGE
PINPOINT TEST EGO - EXHAUST GAS OXYGEN SENSOR
EGO CIRCUIT PIN IDENTIFICATION
1. Warm engine to operating temperature, and let idle. Unplug EGO sensor. Measure voltage between EGO sensor connector (sensor side) NOTE:Enter this procedure only when a Code 14 is displayed during QUICK T EST S procedure or when
directed here from another PINPOINT T EST . T o prevent unnecessary replacem ent of com ponents, note
following non-EEC item s m ay be at fault: unusually high or low atm ospheric pressure, blocked vacuum
lines, or basic m echanical engine com ponents.
Vacuum (In. Hg.)(1) Voltage
03.84
53.36
102.66
151.93
201.26
25.58
(1)Voltage may vary by 15 percent.
NOTE:Enter this test only when a Code 15 (lean) or Code 17 (rich) is displayed during QUICK TESTS
procedure.
CircuitECA PinBOB PinWire Color
EGO
1.3L2N29BLU
1.6L2D29BLK
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and ground. With engine at idle, voltage should fluctuate between 0.2-0.8 volt.
2. Increase and decrease engine speed while reading voltmeter. When engine speed is decreasing, voltage should decrease. When engin e
speed is increasing, voltage should increase. If voltage is within specification, go to next step. If voltage is not within specification,
replace EGO sensor.
3. With ignition off, install BOB. Leave ECA disconnected. Unplug EGO sensor connector. Measure continuity between EGO test pin and
EGO sensor connector wire. If continuity exists, EGO circuit is okay; return to QUICK TESTS if sent here from there. If not sent here
from QUICK TESTS, replace ECA. If voltage is not as specified, repair VMREF wire to VAF. If continuity does not exist, service EGO
sensor wire to ECA.
PINPOINT TEST PRC - FUEL PRESSURE REGULATOR CONTROL SOLENOID

Fig. 13: Identifying PRC Circuit & Connector

PRC CIRCUIT PIN IDENTIFICATION
1. Locate Fuel Pressure Control (PRC) solenoid on cowl panel, next to canister purge solenoid. Unplug PRC solenoid connector. Remo ve
both vacuum lines. Plug vacuum port from engine vacuum source. Apply vacuum to remaining port. Replace PRC solenoid if it does not
hold vacuum.
2. Turn ignition off. Connect BOB. Leave ECA disconnected. Reconnect wiring to PRC solenoid. Turn ignition on. Apply vacuum to PRC
solenoid. Connect jumper wire between PRC test pin on BOB and ground. If vacuum drops to zero, PRC solenoid function is okay.
Return to QUICK TESTS if sent here from there. If vacuum does not drop to zero, go to next step.
3. Turn ignition off. Unplug PRC solenoid connector. Turn ignition on. Measure voltage between VPWR wire on harness connector and
gr o u n d . If vo l t a ge is n o t h igh e r t h a n 1 0 vo l t s, r e p a ir VP WR wir e t o ma in r e l a y. If vo l t a ge is h igh e r t h a n 1 0 vo l t s, go t o n e xt step.
4. Turn ignition off. Unplug PRC solenoid connector. Turn ignition on. Measure voltage between solenoid connector VPWR wire and
solenoid connector SIG wire. Connect jumper wire between PRC test pin on BOB and ground. If voltage is higher than 10 volts only
when solenoid is activated, replace solenoid. If voltage is not higher than 10 volts only when solenoid is activated, go to next step.
5. Turn ignition off. Connect BOB. Leave ECA disconnected. Unplug solenoid connector. Measure resistance between SIG test pin and
solenoid connector SIG wire. If resistance is not less than 5 ohms, repair SIG wire to ECA. If resistance is less than 5 ohms, go t o n e xt
step.
6. Turn ignition off. Connect BOB. Leave ECA disconnected. Unplug solenoid connector. Measure resistance between SIG test pin and all
other test pins. If resistance between SIG PRC test pin and any other pin is less than 5 ohms, repair PRC wire to ECA. If resistance
between PRC test pin and any other pin is greater than 10,000 ohms, replace ECA.
PINPOINT TEST CANP - CANISTER PURGE CONTROL SOLENOID
NOTE:Enter this test only when a Code 25 is displayed during QUICK T EST S procedure or when directed here
from another PINPOINT TEST.
CircuitECA PinBOB PinWire Color
PRC (1.6L)2K31BRN
NOTE:Enter this test only when a Code 26 is displayed during QUICK T EST S procedure or when directed here
from another PINPOINT TEST.
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