Engine Controls - System/component Tests - Eec-Iv Mercury Sable II

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC TESTING article in the ENGINE PERFORMANCE Section. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

Note. For wiring diagrams not shown in testing procedures, see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section.

Note. In the following tests, illustrations are courtesy of Ford Motor Co.

SUPERCHARGER

Note. Supercharger cannot be overhauled. If supercharger malfunctions, replace entire supercharger assembly.

Supercharger Noisy

1. Air or vacuum leaks. Check hoses, tubes and flange joints for leaks.
2. Exhaust leaks. Check rubber tube to EGR valve for looseness and damage.
3. By-pass actuator not opening. Check by-pass vacuum tube for damage, restriction and incorrect routing. Check valve and actuator rod for restriction. Ensure actuator rod rests against lever stop when vacuum is less than 3 in. Hg. Actuator rod should be fully open (horizontal) when vacuum is greater than 8 in. Hg.
4. Low supercharger oil level. Replace supercharger if no oil is present.
5. Contaminated supercharger. Remove outlet adapter. Inspect rotors for foreign objects. Replace supercharger if rotors are damaged.
6. Gear rattle is normal and does not affect performance. Excessive gear rattle can be caused by actuator valve not opening.
7. Chirping is normal and does not affect performance. Excessive chirping can be caused by actuator valve not opening.

Low Boost

1. Air or vacuum leaks. Check hoses, tubes and flange joints for leaks.
2. Restricted air inlet. Check air filter and air induction system.
3. Supercharger not rotating. Check drive belt. Remove outlet adapter. Inspect rotors for damage and seizure. Replace supercharger if rotors are damaged.
4. By-pass actuator not closing. Check valve and actuator rod for restriction. Ensure actuator rod rests against lever stop when vacuum is less than 3 in. Hg.
5. Insufficient flow from supercharger. Remove outlet adapter. Ensure rotors turn when pulleys are rotated. Replace supercharger if rotors do not turn.

High Boost

1. Check for plugged exhaust system.
2. Check for plugged intercooler tubes.
3. Check for correct supercharger pulleys.

Oil Leakage

1. Some oil seepage may occur with mileage. Ensure PCV system is not restricted. Ensure oil fill plug is tight. Check oil level, and top off as necessary. If oil loss is excessive, replace supercharger.

Intake Manifold Runner Control Valve (Taurus SHO & Mark VIII)

With engine off, disconnect vacuum lines from both intake air valves. Apply 10 in. Hg vacuum to each air valve. Replace air valves if linkage does not respond and/or vacuum is not held.

Intake Air Control Solenoid (Taurus SHO & Mark VIII)

With engine off, wait 10 seconds, and then disconnect Intake Air Control (IAC) solenoid. Solenoid is mounted on firewall side of intake plenum. Using an ohmmeter on 200-ohm scale, check resistance between IAC solenoid terminals. Resistance should be 50-100 ohms. If resistance is not as specified, replace solenoid.

Ground Circuits

1. Using a DVOM, check for continuity to ground on PCM terminals No. 40 and 60. (Scheme 165) Resistance should be zero ohms. If resistance is not zero ohms, repair open to ground.
2. Using a voltmeter, touch negative lead of voltmeter to a good ground. Touch positive lead of voltmeter to each ground terminal. With vehicle running, voltmeter should indicate less than 0.5 volt. If voltmeter reading is greater than 0.5 volt, check for open circuit, corrosion and loose connection on ground lead.

Power Circuits

Using a voltmeter, check for battery voltage between PCM terminal No. 1 (KAPWR) and ground. (Scheme 165) Check for battery voltage at terminals No. 37 and 57 (VPWR). If battery voltage is not present, EEC power relay is not supplying power. See CIRCUIT TEST B in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

PCM Connector Terminal Identification. Scheme 165

ENGINE SENSORS & SWITCHES (PCM INPUTS)

Note. For additional sensor testing specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section.

A/C CUTOUT

1. Faults in system or circuits should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, See CIRCUIT TEST KM in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for testing.

AIR CHARGE TEMPERATURE (ACT) SENSOR

ACT sensor requires a 5-volt reference signal during engine operation. With sensor disconnected, sensor may be checked by measuring resistance between sensor terminals. For specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section.. For additional testing information, see CIRCUIT TEST DA in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

BAROMETRIC PRESSURE (BARO) SENSOR

Faults in barometric pressure sensor or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If code has not been set, see CIRCUIT TEST DF in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for sensor specifications.

CYLINDER IDENTIFICATION (CID)

CID is integral with Camshaft Position (CMP) sensor or Crankshaft Position (CKP) sensor. Disconnect sensor connector. See CID SENSOR LOCATION table. Check connector for wear or corrosion. For additional circuit testing information, see CIRCUIT TEST DR in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section and PIN VOLTAGE CHART S article in the ENGINE PERFORMANCE Section.

CID SENSOR LOCATION (1)

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

ECT sensor requires a 5-volt reference signal during engine operation. With sensor disconnected, sensor may be checked by measuring resistance between sensor terminals. For specifications, see SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section.. For additional sensor circuit testing, see CIRCUIT TEST DA in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

EGR VALVE POSITION (EVP) SENSOR

Faults in sensor or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section, SENSOR RANGE CHARTS article in the ENGINE PERFORMANCE Section and PIN VOLTAGE CHART S article in the ENGINE PERFORMANCE Section.

EGR VACUUM REGULATOR (EVR) SOLENOID

Faults in sensor or circuit should set a service code. If service code has not been set, disconnect sensor. Measure resistance between sensor terminals. Replace sensor if resistance is not 20-70 ohms.

HEATED GAS OXYGEN SENSOR (HO2S)

Vehicle may be equipped with one or 2 HO2S sensors. They are located in exhaust pipe, upstream of catalytic converters. Faults in sensor or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, ensure none of these conditions exist

1. Moisture inside sensor/harness connector.
2. HO2S sensor coated with contaminants.
3. Sensor circuit open or shorted to ground.

If necessary, see CIRCUIT TEST H in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for additional specifications and circuit testing procedures.

INERTIA FUEL SHUTOFF (IFS) SWITCH

1. Turn ignition off. Locate IFS switch in rear of vehicle. Ensure IFS reset button is not in upper (tripped) position. Using a jumper lead, ground FP terminal at Diagnostic Link Connector (DLC). (Scheme 168)
2. Turn ignition on, leaving engine off. Leaving inertia switch connector attached, check voltage at connector. If 10.5 volts is not present, repair circuit. If 10.5 volts is present at one terminal only, replace inertia switch.
3. If 10.5 volts is present at both terminals, turn ignition off. Measure resistance between terminals on 2-wire switches. On 1.9L, measure resistance between GND and FP terminals. (Scheme 166)
4. With reset button pushed down, resistance should be 5 ohms or less. If resistance is greater than 5 ohms, replace switch. For additional circuit testing information, refer to CIRCUIT TEST J in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Identifying Inertia Switch Terminals (1.9L). Scheme 166

KNOCK SENSOR (KS)

KS is located on cylinder block. Sensor is tested by substitution or by manually generating a knock to ensure sensor will set a service code. Faults in sensor or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, see CIRCUIT TEST DG in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for additional sensor circuit testing procedures.

MASS AIRFLOW (MAF) SENSOR

1. Faults in MAF sensor or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, install Breakout Box (T83L-50-EEC-IV), leaving PCM connected. Start engine, and allow it to idle.
2. On 2.3L OHC, measure voltage between test pin No. 14 and negative battery terminal. On all other models, measure voltage between test pin No. 50 and negative battery terminal. On all models, if voltage is not .36-1.50 volts, replace MAF sensor. If voltage is .36-1.50 volts, MAF sensor is okay. See CIRCUIT TEST DC in «G - TESTS W/CODES - EEC-IV (1.9L)»(ref-22814) article in the ENGINE PERFORMANCE Section for circuit testing.

POWER STEERING PRESSURE SWITCH (PSPS)

Faulty PSPS or circuit should set a diagnostic trouble code. See QUICK TEST in G - TESTS W/CODES - EEC-IV (1.9L) article in the ENGINE PERFORMANCE section. If diagnostic trouble code has not been set, see CIRCUIT TEST FF in G - TESTS W/CODES - EEC-IV (1.9L) article in the ENGINE PERFORMANCE section for testing.

PRESSURE FEEDBACK ELEC. (PFE) EGR SENSOR/DELTA PFE SENSOR

1. Faults in sensor or circuit should set a service code. If service code has not been set, install Breakout Box (014-00322). Connect PCM to breakout box. Connect hand vacuum/pressure pump to sensor. Connect DVOM to SIG RTN test terminal and ground. Monitor DVOM while applying vacuum or pressure and compare to specifications. See DELTA PRESSURE FEEDBACK ELECTRONIC (DPFE) EGR SPECIFICATIONS or PRESSURE FEEDBACK ELECTRONIC (PFE) EGR SPECIFICATIONS table. Replace sensor if not within specification.
2. The resistance substrate can be checked using an analog ohmmeter connected between VREF terminal and PFE or DPFE terminal. Exercise sensor with hand vacuum/pressure pump and watch for jerks or jumps toward infinity. No specific resistance specifications are available.

DPFE SENSOR SPECIFICATIONS

PFE SENSOR SPECIFICATIONS

THROTTLE POSITION (TP) SENSOR

Faults in TP sensor or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, see THROTTLE POSITION SENSOR (TPS) ADJUSTMENT in BASIC TESTING article in the ENGINE PERFORMANCE Section for specifications.

VEHICLE SPEED SENSOR (VSS)

1. Faults in VSS or circuit should set service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. Disconnect VSS electrical connector if service code has not been set.
2. Using DVOM, measure resistance across sensor terminals. Resistance should be 190-250 ohms. Replace sensor if not within specification. If sensor is within specification, see CIRCUIT TEST DP in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for additional circuit testing.

Constant Control Relay Module (CCRM)

Faults in CCRM or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, see CIRCUIT TEST X in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for CCRM testing.

Variable Control Relay Module (VCRM)

Faults in VCRM or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, see CIRCUIT TEST XB in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for testing.

RELAYS

Note. Fuel pump relay is located inside Integrated Relay Control Module (CCRM) on 2.3L, 3.0L & 3.8L. For CCRM test procedures, see CIRCUIT TEST X in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Fuel Pump Relay

Remove relay from vehicle. Connect battery voltage to terminal "C". (Scheme 167) Ground terminal "D". Measure resistance between terminals "A" and "B". Resistance should be less than one ohm with power applied and greater than 10 k/ohms with power removed.

Identifying Fuel Pump Relay Terminals (1.9L, 4.6L & 5.0L). Scheme 167

Air Management Solenoid

Faults in secondary air management solenoids or circuits should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, disconnect both solenoid harness connectors. Measure resistance across terminals. Resistance should be 50-100 ohms. If resistance is not as specified, replace solenoid. If resistance is as specified, see CIRCUIT TEST KC in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for additional circuit testing.

Canister Purge (CANP) Solenoid

1. Faults in CANP solenoid or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, disconnect CANP solenoid harness connector.
2. Measure resistance across CANP solenoid terminals. Resistance should be 40-90 ohms. If resistance is not as specified, replace CANP solenoid. If resistance is as specified, disconnect vacuum hose at CANP solenoid on manifold vacuum side.
3. Apply 16 in. Hg vacuum to manifold vacuum side of solenoid. CANP solenoid should hold vacuum for 20 seconds. If CANP solenoid does not hold vacuum for 20 seconds, replace CANP solenoid. If CANP solenoid holds vacuum for 20 seconds, see CIRCUIT TEST KD in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for circuit testing.

EGR Solenoid

See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS.

Idle Air Control Solenoid

See AIR INDUCTION SYSTEMS in this article. If additional testing is required, see CIRCUIT TEST KE in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for circuit testing.

FUEL SYSTEM

Note. In following test procedures, KOEO refers to Key On Engine Off and KOER refers to Key On Engine Running.

Except 1.9L

1. Remove fuel cap to release fuel tank pressure. Remove relief valve cap. Relief valve is located on fuel supply manifold. Using EFI Pressure Gauge (T80L-9974-B), release fuel pressure from relief valve (Schrader valve).
2. If fuel pressure gauge is not available, disconnect electrical connector to inertia switch located on left side of luggage compartment. Crank engine for 15 seconds to reduce system pressure.

1.9L

Depress retaining clips and remove rear seat cushion. Disconnect fuel pump connections. Start engine, and operate it until it stalls. Turn ignition off. Reconnect fuel pump. Install rear seat cushion.

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING article in the ENGINE PERFORMANCE Section. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

See RELAYS under MODULES, RELAYS & SOLENOIDS.

See MODULES under MODULES, RELAYS & SOLENOIDS.

See MODULES under MODULES, RELAYS & SOLENOIDS.

Scheme 168

1. Visually inspect fuel delivery system for leaks and damaged lines. Ensure battery is fully charged and fuses are okay. Check fuel tank contents and fuel gauge accuracy.
2. Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE. Install fuel pressure gauge. Turn ignition on to activate pump. Check and record fuel pressure. For fuel pressure specifications, see «FUEL PRESSURE SPECIFICATIONS»(/mercury/sable/ii-1991-1995/remont/specifications/#fuel-pressure-specifications) article. Proceed to appropriate step as indicated: If fuel pressure is within specification, go to step 3). If fuel pressure is zero, go to step 5). If fuel pressure is low, go to step 6). If fuel pressure is high, go to FUEL PRESSURE REGULATOR. CAUTION: Inspect fuel system for leaks and damage before testing fuel pump.
3. Check fuel injectors. See FUEL CONTROL. Start or crank engine. Using a mechanic's stethoscope, listen for regularly spaced operating clicks at each injector. If clicks are present, check fuel injectors for flow and leakage.
4. If clicks are not present, check fuel injector resistance. See FUEL CONTROL. Replace injectors not within specification. If injectors are within specification, check for 12 volts at each injector lead. If voltage is present, circuit is okay. Clean or replace injectors as necessary. If voltage is not present at injectors, see CIRCUIT TEST H in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for circuit diagnosis.
5. If fuel pressure is zero, ensure battery is fully charged. Ensure connection is okay at pump/sending unit. Turn ignition off. Using a jumper lead, ground FP terminal at Diagnostic Link Connector (DLC). (Scheme 168) Turn ignition on, leaving engine off. Listen for sound of fuel pump. If pump is running, go to next step. If pump is not running, go to step 7). (Scheme 168): Identifying Fuel Pump Connector Terminals & Circuits
6. Check condition of fuel filter. Replace filter if necessary, and repeat step 1). If filter is okay, check fuel pressure regulator. See FUEL PRESSURE REGULATOR.
7. Turn ignition off. Disconnect fuel pump/sending unit connector. Measure resistance between pump ground at connector and chassis ground. If resistance is greater than one ohm, repair open circuit to ground. If resistance is not greater than one ohm, go to next step.
8. Ensure ignition is off and battery is fully charged. Disconnect harness connector from pump/sending unit. Ground FP terminal at DLC. Turn ignition on. Measure voltage at pump power terminal of pump/sending unit connector. If voltage is greater than 10.5 volts, replace pump/sending unit assembly. If voltage is not greater than 10.5 volts, go to next step.
9. Check inertia switch. See ENGINE SENSORS & SWITCHES (PCM INPUTS). Check fuel pump relay (if equipped). See RELAYS under MODULES, RELAYS & SOLENOIDS. Check Constant Control Relay Module (CCRM) (if equipped). See MODULES under MODULES, RELAYS & SOLENOIDS. Check engine compartment for leaks and ensure engine produces normal engine vacuum. See FUEL PRESSURE REGULATOR.

Fuel Pressure Regulator

1. Turn ignition off. Ensure vacuum hose is connected to fuel pressure regulator. Start and run engine for 10 seconds. Stop engine, and wait 10 seconds. Start and run engine for 10 seconds. Stop engine. Remove vacuum hose from pressure regulator. If fuel is present in vacuum port, replace fuel pressure regulator. If fuel is not present, go to step 2). CAUTION: Inspect fuel system for leaks and damage before testing fuel pump.
2. Connect fuel pressure gauge to Schrader valve on fuel rail. Ground FP terminal at DLC. (Scheme 168) Turn ignition on. Operate fuel pump for 30 seconds. Stop fuel pump, and check fuel pressure gauge. Ensure fuel pressure is within specification. For fuel pressure specifications, see «FUEL PRESSURE SPECIFICATIONS»(/mercury/sable/ii-1991-1995/remont/specifications/#fuel-pressure-specifications) article.Ensure pressure does not drop greater than 2 psi (.2 kg/cm 2 ) in 3 minutes.
3. If fuel pressure is within specification, fuel pressure regulator is okay and test is compete. If fuel pressure is not within specification, check fuel filter, and service as necessary. If fuel pressure is still not within specification, install vacuum gauge to intake manifold. Start engine, and observe vacuum and fuel pressure gauge while accelerating and decelerating engine.
4. When engine is accelerating, vacuum reading should decrease and fuel system pressure should increase. When engine is decelerating, vacuum reading should increase and fuel system pressure should decrease. If readings are as indicated, fuel system is okay and test is compete.
5. If gauge readings are not as indicated, turn ignition off. Disconnect and plug fuel pressure regulator hose. Attach vacuum pump to fuel pressure regulator. Start engine. Apply vacuum to pressure regulator while observing fuel pressure gauge. If fuel pressure changes as vacuum changes, repair restriction in vacuum supply hose. If fuel pressure does not change as vacuum changes, go to step 6).
6. Ensure ignition is off. Relieve fuel pressure. Remove fuel pressure regulator. Check "O" ring, gasket and mounting surfaces for cracks, cuts and other damage. (Scheme 169) Connect vacuum pump to fuel return tube. Apply 20 in. Hg. If maximum vacuum loss exceeds 10 in. Hg in 10 seconds, replace regulator. If maximum vacuum loss does not exceed 10 in. Hg in 10 seconds, recheck entire fuel delivery system for cause of fuel pressure loss.

Identifying Fuel Pressure Regulator Components. Scheme 169

Fuel Injector Check

1. Connect tachometer to engine. Run engine at idle. Disconnect and reconnect injectors individually. When disconnected, each injector should cause a momentary drop in engine speed of at least 100 RPM. Engine RPM drop should only be momentary as PCM will attempt to reestablish correct idle RPM.
2. Replace any injectors which do not cause sufficient drop in engine speed. When test is complete, check idle speed. Refer to emission control specifications on decal in engine compartment or see IDLE SPEED in the appropriate ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

Fuel Injector Circuit

Disconnect injector harness connectors. Using digital ohmmeter, check connector terminal resistance of each injector. Individual injector resistance should be 13-16 ohms on all models. On non-sequential PFI engines, disconnect injector bank harness connector. Check resistance of injector bank. See INJECTOR BANK RESISTANCE table. Repair wiring or any injector not within specification.

INJECTOR BANK RESISTANCE (1)

IDLE CONTROL SYSTEM

Note. See AIR INDUCTION SYSTEMS in this article. If additional testing is required, see CIRCUIT TEST KE in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for circuit testing.

IGNITION SYSTEM

Note. For additional information and descriptions, see IGNITION SYSTEM in THEORY/OPERATION article in the ENGINE PERFORMANCE Section. Perform appropriate SPARK OUTPUT CHECK under IGNITION CHECKS in BASIC TESTING article in the ENGINE PERFORMANCE Section before entering these tests.

IGNITION SYSTEM ACRONYMS

IGNITION SYSTEM IDENTIFICATION

Preliminary Check

Perform following preliminary checks

1. Visually inspect engine compartment to verify vacuum hoses and spark plug wires are properly routed and securely connected.
2. Examine all wiring harnesses and connectors for damage.
3. Ensure ICM is securely fastened to distributor base or cowl.
4. Ensure battery is fully charged.
5. All accessories should be off during diagnosis.

Test Equipment

Following test equipment should be used in DI system tests.

1. Spark Tester (D81P-6666-A Or D89P-6666-A)
2. Digital Volt-Ohmmeter (DVOM)
3. 12-Volt Test Light
4. Remote Starter Switch
5. EEC-IV Diagnostic Cable (007-00097)
6. EEC-IV Breakout Box (T83L-50-EEC-IV)
7. Inductive Timing Light

Diagnostic Aids

Major difference between Computer Controlled Dwell (CCD) and non-CCD systems is CCD system does not receive a start signal from ignition switch at ICM (terminal No. 4) during engine cranking. CCD systems send an additional coil negative (-)/tach circuit signal to PCM from ignition module (terminal No. 4) labeled Filtered Tach Output (FTO). Following information should be noted during testing

1. All voltage readings given in test procedures are based on values obtained using a standard DVOM such as Rotunda (007-00001) or Fluke (20 or 70 Series). DO NOT use RMS type meter.
2. When instructed to inspect a wiring harness, perform both a visual inspection and a continuity test.
3. When making voltage checks, ground connections should be made at negative battery terminal or cast iron surface of engine.
4. When making measurements on a wiring harness or connector, perform a wiggle test while measuring.
5. When making voltage checks, ground readings are defined as a value of less than 1.0 volt. Battery voltage is defined as a value of 10-14 volts.
6. Test procedures are intended to identify faulty components or wiring while fault is present. If complaint is an intermittent condition, refer to appropriate H - EEC-IV TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Scheme 170

Scheme 171

1. Ensure that SPARK OUTPUT CHECK has been performed. See IGNITION CHECKS in BASIC TESTING article in the ENGINE PERFORMANCE Section article. Turn ignition off. Connect EEC-IV Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. (Scheme 170) Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position. Apply DI overlay on breakout box. DO NOT connect EEC-IV Diagnostic Cable and PCM to EEC-IV Breakout Box simultaneously. (Scheme 170): EEC-IV Diagnostic Cable (007-00097) Installation (DI)
2. Turn ignition on. Put DVOM on DC voltage scale. Measure voltage between J5 (TFI PWR) and J7 (B -). If voltage is less than 10 volts DC, repair open in TFI PWR circuit to ICM. If voltage is greater than 10 volts DC, put DVOM on AC voltage scale.
3. Measure voltage between J7 (B -) and J15 (PIP) while cranking engine. If voltage is not 3.0-8.5 volts AC, go to step 5). If voltage is 3.0-8.5 volts AC, measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If voltage is not 3.0-8.5 volts AC, go to step 9). If voltage is 3.0-8.5 volts AC, turn ignition off. Connect diagnostic cable to ignition coil wiring harness. Leave ignition coil disconnected.
4. Set DVOM on DC voltage scale. Turn ignition on. Measure voltage between J2 (COIL PWR) and J7 (B -). If voltage is not greater than 10 volts DC, repair open circuit in ignition coil circuit. If voltage is greater than 10 volts DC, turn ignition off. Connect B + lead of diagnostic cable to positive battery terminal. Connect test light to J1 (B +) and J3 (COIL-). Crank engine. If test light does not flash brightly, go to step 16). If test light flashes brightly, replace coil, and perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.
5. If voltage is not 3.0-8.5 volts AC in step 3), turn diagnostic cable switch to PIP OPEN position. Measure voltage between J7 (B -) and J15 (PIP) while cranking engine. If voltage is not 3.0-8.5 volts AC, go to step 8). If voltage is 3.0-8.5 volts AC, turn ignition off.
6. Turn diagnostic cable switch to NORMAL position. Put DVOM on DC voltage scale. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness. Turn ignition on. Measure voltage between J7 (B -) and J15 (PIP). If voltage is greater than 0.5 volt, repair short in PIP circuit between PCM and ICM.
7. If voltage is less than 0.5 volt, turn ignition off. Measure resistance between J7 (B -) and J15 (PIP). If resistance is greater than 10,000 ohms, replace PCM. If resistance is 10,000 ohms or less, repair short in PIP circuit between PCM and ICM.
8. If voltage is not 3.0-8.5 volts AC in step 5), turn ignition off. Remove ICM from distributor. Measure resistance of ICM circuits. See ICM RESISTANCE table. (Scheme 171) If resistance is not as specified, replace ICM. If resistance is as specified, check stator and wiring inside distributor. Repair as necessary. If stator and wiring are okay, replace Camshaft Position (CMP) sensor. ICM RESISTANCE Between Terminals Ohms PIP (In) & PIP (Out) Less Than 150 PIP PWR & TFI PWR Less Than 150 GND & PIP (In) Greater Than 500 GND & IGN GND Less Than 5 PIP (In) & PIP PWR 900-1500 (Scheme 171): Identifying Distributor Mounted ICM & Connector Terminals
9. If voltage is not 3.0-8.5 volts AC in step 3), turn diagnostic cable switch to SPOUT OPEN position. Measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If voltage is 3.0-8.5 volts AC, replace ICM.
10. If voltage is not 3.0-8.5 volts AC, turn ignition off. Turn diagnostic cable switch to NORMAL position. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT).
11. If voltage is less than 0.5 volt DC, go to step 12). If voltage is greater than 0.5 volt DC, turn ignition off. Disconnect PCM. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If voltage is less than 0.5 volt DC, go to step 13). If voltage is greater than 0.5 volt DC, repair short to power in SPOUT circuit between PCM and ICM.
12. Turn ignition off. Measure resistance between test pin J7 (B -) and J10 (SPOUT). If resistance is less than 10,000 ohms, disconnect PCM. Measure resistance between J7 (B -) and J10 (SPOUT). If resistance is still less than 10,000 ohms, repair short to ground in SPOUT circuit between PCM and ICM. If resistance is greater than 10,000 ohms, go to step 13).
13. Measure resistance between breakout box test pin J15 (PIP) and PCM wiring harness connector terminal No. 56 (PIP). If resistance is greater than 5 ohms, repair open in PIP circuit between PCM and ICM. If resistance is less than 5 ohms, go to next step.
14. Connect diagnostic cable to ICM. Measure resistance between breakout box test pin J7 (B -) and PCM wiring harness connector terminal No. 16 (IGN GND). If resistance is less than 5 ohms, replace PCM. If resistance is greater than 5 ohms, disconnect diagnostic cable from ICM.
15. Measure resistance between breakout box test pin J9 (IGN GND) and PCM wiring harness connector terminal No. 16 (IGN GND). If resistance is less than 5 ohms, replace ICM. If resistance is greater than 5 ohms, repair open in IGN GND circuit between PCM and ICM.
16. If test light does not flash brightly in step 4), disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness. Disconnect diagnostic cable from positive battery cable. Measure resistance between J3 (COIL-) and J4 (COIL-).
17. If resistance is greater than 5 ohms, repair open in COIL- circuit between ignition coil and ICM. If resistance is less than 5 ohms, put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J3 (COIL-) and J7 (B -). If voltage is greater than 5.5 volts DC, repair short to power in COIL- circuit between ignition coil and ICM. If voltage is less than 5.5 volts DC, go to next step.
18. Turn ignition off. Measure resistance between J3 (COIL-) and J7 (B -). If resistance is less than 10,000 ohms, repair short in COIL- circuit between ignition coil and ICM. If resistance is greater than 10,000 ohms, replace ICM.

Distributor Mounted ICM System Diagram (2.3L HSC & 3.0L). Scheme 172

Distributor Mounted ICM System Diagram (Mustang 5.0L). Scheme 173

Scheme 174

1. Ensure that SPARK OUTPUT CHECK has been performed. See IGNITION CHECKS in BASIC TESTING article in the ENGINE PERFORMANCE Section. Turn ignition off. Connect EEC-IV Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. (Scheme 170) Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position. Apply DI overlay on breakout box. DO NOT connect EEC-IV Diagnostic Cable and PCM to EEC-IV Breakout Box simultaneously.
2. Turn ignition on. Put DVOM on DC voltage scale. Measure voltage between J5 (TFI PWR) and J7 (B -). If voltage is less than 10 volts DC, repair open in TFI PWR circuit to ICM. (Scheme 175) If voltage is greater than 10 volts DC, put DVOM on AC voltage scale.
3. Measure voltage between J7 (B -) and J15 (PIP) while cranking engine. If voltage is not 3.0-8.5 volts AC, go to step 6). If voltage is 3.0-8.5 volts AC, measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If voltage is not 3.0-8.5 volts AC, go to step 13). (Scheme 174): Identifying Remote Mounted ICM & Connector Terminals
4. If voltage is 3.0-8.5 volts AC, turn ignition off. Connect diagnostic cable to ignition coil wiring harness. Leave ignition coil disconnected. Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J2 (COIL PWR) and J7 (B -). If voltage is not greater than 10 volts DC, repair open in ignition coil circuit.
5. If voltage is greater than 10 volts DC, turn ignition off. Connect B + lead of diagnostic cable to positive battery terminal. Connect test light to J1 (B +) and J3 (COIL-). Crank engine. If test light does not flash brightly, go to step 19). If test light flashes brightly, replace ignition coil.
6. If voltage between J7 and J15 is not 3.0-8.5 volts AC in step 3), connect diagnostic cable CMP (PIP) sensor tee. Put DVOM on DC voltage scale. Measure voltage between J7 (B -) and J22 (PIP PWR) on 8-pin connector type or J7 (B -) and J27 (CMP PWR) on 4-pin connector type. If voltage is not greater than 10 volts DC, repair open in PIP PWR circuit.
7. If voltage is greater than 10 volts DC, turn diagnostic cable switch to PIP OPEN position. Put DVOM on AC voltage scale. While cranking engine, measure voltage between J7 (B -) and J34 (PIP A) on 8-pin connector type or J7 (B -) and J13 (PIP) on 4-pin connector type. If voltage is not 3.0-8.5 volts AC, check PIP wiring and connector. If wiring and connector are okay, replace Camshaft Position (CMP) sensor.
8. If voltage is 3.0-8.5 volts AC, turn ignition off. Turn diagnostic cable switch to NORMAL position. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness. While cranking engine, measure voltage between J7 (B -) and J34 (PIP A) on 8-pin connector type or J7 (B -) and J13 (PIP) on 4-pin connector type.
9. If voltage is 3.0-8.5 volts AC, replace ICM. If voltage is not 3.0-8.5 volts AC, disconnect PCM. While cranking engine, measure voltage between J7 (B -) and J34 (PIP A) on 8-pin connector type or J7 (B -) and J13 (PIP) on 4-pin connector type. If voltage is 3.0-8.5 volts AC, replace PCM.
10. If voltage is not 3.0-8.5 volts AC, turn ignition off. Disconnect diagnostic cable from CMP sensor. Leave diagnostic cable attached to CMP sensor wiring harness. Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J7 (B -) and J34 (PIP A) on 8-pin connector type or J7 (B -) and J13 (PIP) on 4-pin connector type.
11. If voltage is greater than 0.5 volt, repair PIP A circuit short to power between CMP sensor and PCM. If voltage is less than 0.5 volt, measure voltage between J7 (B -) and J41 (PIP B). If voltage is greater than 0.5 volt, repair PIP B circuit short to power between CMP sensor and PCM. If voltage is less than 0.5 volt, turn ignition off.
12. Measure resistance between J7 (B -) and J41 (PIP B). If resistance is greater than 10,000 ohms, repair short to ground in PIP A circuit between PCM and CMP sensor. If resistance is less than 10,000 ohms, repair short to ground in PIP B circuit between CMP sensor and ICM. NOTE: If engine starts in step 13), continue testing.
13. If voltage between J7 and J10 is not 3.0-8.5 volts AC in step 3), turn diagnostic cable switch to SPOUT OPEN position. Measure voltage between J7 (B -) and J10 (SPOUT) while cranking engine. If voltage is 3.0-8.5 volts AC, replace ICM. If voltage is not 3.0-8.5 volts AC, turn ignition off. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness.
14. Turn diagnostic cable switch to NORMAL position. Put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If voltage is 0.5 volt DC or more, go to step 15). If voltage is less than 0.5 volt DC, disconnect PCM. Turn ignition on. Measure voltage between J7 (B -) and J10 (SPOUT). If voltage is less than 0.5 volt DC, go to step 16). If voltage is greater than 0.5 volt, repair short in SPOUT circuit between PCM and ICM.
15. If voltage is less than 0.5 volt DC in step 14), turn ignition off. Measure resistance between J7 (B -) and J10 (SPOUT). If resistance is greater than 10,000 ohms, go to step 16). If resistance is less than 10,000 ohms, disconnect PCM. Measure resistance between J7 (B -) and J10 (SPOUT). If resistance is still less than 10,000 ohms, repair short in SPOUT circuit between PCM and ICM.
16. Turn ignition off. Disconnect PCM. Measure voltage between J7(B -) and J56 (SPOUT). Go to step 18) if voltage is not 3.0-8.5 volts AC. If voltage is 3.0-8.5 volts AC, turn ignition off. Connect diagnostic cable to ICM. Measure resistance between breakout box test pin J7 (B -) and PCM wiring harness connector terminal No. 16 (IGN GND).
17. If resistance is less than 5 ohms, replace PCM. If resistance is greater than 5 ohms, connect diagnostic cable to CMP sensor. Measure resistance between J7 (B -) and J35 (IGN GND) on 8-pin connector type or J7 (B -) and J19 (IGN GND) on 4-pin connector type. If resistance is 5 ohms or less, repair open in IGN GND circuit between PCM and CMP sensor. If resistance is greater than 5 ohms, replace CMP sensor.
18. If voltage is 3.0-8.5 volts AC in step 16), turn diagnostic cable switch to PIP OPEN position. Connect diagnostic cable between CMP sensor and sensor wiring harness connector. Crank engine while measuring voltage between J7 (B -) and J34 (PIP A) on 8-pin connector type or J7 (B -) and J13 (PIP) on 4-pin connector type. If voltage is 3.0-8.5 volts AC, repair PIP circuit between CMP sensor and PCM. If voltage is not 3.0-8.5 volts AC, replace CMP sensor.
19. If test light does not flash brightly in step 5), turn ignition off. Disconnect diagnostic cable from ICM. Leave diagnostic cable attached to ICM wiring harness. Disconnect diagnostic cable from positive battery cable. Measure resistance between J3 (COIL-) and J4 (COIL-).
20. If resistance is greater than 5 ohms, repair open in COIL- circuit between ignition coil and ICM. Repeat QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If resistance is less than 5 ohms, measure resistance between J3 (COIL-) and J7 (B -).
21. If resistance is less than 10,000 ohms, put DVOM on DC voltage scale. Turn ignition on. Measure voltage between J3 (COIL-) and J7 (B -). If voltage is greater than 5.5 volts DC, repair short to power in COIL- circuit between ignition coil and ICM. If voltage is less than 5.5 volts DC, go to next step.
22. Turn ignition off. Measure resistance between J3 (COIL-) and J7 (B-). If resistance is less than 10,000 ohms, repair COIL- circuit short to ground between ignition coil and ICM. If resistance is greater than 10,000 ohms, go to next step.
23. Leave ignition off. Measure resistance between J7 (B -) and J9 (GND). If resistance is less than 5 ohms, replace ICM. If resistance is greater than 5 ohms, connect diagnostic cable between CMP sensor and sensor wiring harness connector.
24. Measure resistance between J7 (B -) and J28 (GND) on 8-pin connector type or J7 (B -) and J26 (GND) on 4-pin connector type. If resistance is 5 ohms or less, repair open in GND circuit between CMP sensor and ICM. If resistance is greater than 5 ohms, check ground circuit. If ground circuit is okay, replace CMP sensor. Perform QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

ICM System Diagram (3.8L Ex. SC, Cougar/Thunderbird 5.0L). Scheme 175

No Start With Spout Conn. Disconnected (Remote Mounted ICM)

1. Ensure that SPARK OUTPUT CHECK has been performed. See IGNITION CHECKS in BASIC TESTING article in the ENGINE PERFORMANCE Section. Turn ignition on. Ensure battery has 12 volts.
2. Turn ignition off. Connect DI Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. (Scheme 170) Leave B+ lead disconnected. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position. Apply DI overlay on breakout box. WARNING: DO NOT connect EEC-IV Diagnostic Cable and PCM to EEC-IV Breakout Box simultaneously.
3. Disconnect SPOUT connector. Set DVOM on A/C scale. Crank engine while measuring voltage between J7 (B --) and J15 (PIP). If voltage is 3.0-8.5 volts AC, replace ICM. If voltage is not 3.0-8.5 volts AC, connect diagnostic cable to CMP sensor and sensor connector.
4. Turn switch to PIP OPEN position. Crank engine while measuring voltage between J7 (B --) and J41 (PIP B). If voltage is 3.0-8.5 volts AC, repair open in PIP circuit between ICM and CMP sensor. If voltage is not 3.0-8.5 volts AC, check CMP wiring harness connector. If connector is okay, replace CMP sensor.

Continuous Memory Code 18 Or 212 (IDM Missing)

1. Ensure that SPARK OUTPUT CHECK has been performed. See IGNITION CHECKS in theF - BASIC TESTING article in the ENGINE PERFORMANCE Section. Turn ignition on.
2. Turn ignition off. Connect DI Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. (Scheme 170) Leave B+ lead disconnected. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in NORMAL position.
3. Apply DI overlay on breakout box. Disconnect PCM. For CCD (Black module) equipped systems, go to step 6). For non-CCD (Gray module) equipped systems, set DVOM on DC scale. Disconnect ignition coil wiring harness connector. Turn ignition on.
4. Measure voltage between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If voltage is greater than 5.0 volts DC, repair IDM circuit short to power between PCM and IDM 22K resistor. If voltage is less than 5.0 volts DC, turn ignition off.
5. Measure resistance between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If resistance is less than 10,000 ohms, repair IDM circuit short to ground between PCM and IDM 22K resistor. If resistance is 10,000 ohms or more, measure resistance between J4 (COIL-) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If resistance is not 20,000-24,000 ohms, repair open or shorted IDM circuit.
6. Turn ignition off. Set DVOM on AC scale. Crank engine while measuring voltage between J7 (B -) at breakout box and terminal No. 4 (IDM) at PCM wiring harness connector. If voltage is greater than 1.0 volt AC, replace PCM. If voltage is not greater than 1.0 volt AC, turn ignition off.
7. Disconnect diagnostic connector from ICM. Leave ICM wiring harness connector connected to diagnostic cable. Set DVOM on DC scale. Turn ignition on. Measure voltage between J7 (B-) and J23 (IDM). If voltage is less than 0.5 volt, repair short to power in IDM circuit between PCM and ICM wiring harness connector.
8. If voltage is 0.5 volt or more, turn ignition off. Measure resistance between J7 (B-) and J23 (IDM). If resistance is less than 10,000 ohms, repair short to ground in IDM circuit between PCM and ICM wiring harness connector. If resistance is greater than 10,000 ohms, measure resistance between and J23 (IDM) and terminal No. 4 of PCM wiring harness connector. If resistance is 5 ohms or less, replace ICM. If resistance is greater than 5 ohms, repair open in IDM circuit between PCM and ICM wiring harness connector.

KOER Code 18 Or 213 (Incorrect Ignition Timing)

1. Check ignition timing. See IGNITION TIMING in BASIC TESTING article in the ENGINE PERFORMANCE Section. If ignition timing is correct, testing is complete. If ignition timing is not correct, turn ignition off.
2. Connect DI Diagnostic Cable (007-00097) to EEC-IV Breakout Box (T83L-50-EECIV), negative battery terminal and ICM. (Scheme 170) Leave B+ lead disconnected. Ensure PIP OPEN/NORMAL/SPOUT OPEN switch is in SPOUT OPEN position. Apply DI overlay on breakout box.
3. Set DVOM on DC scale. Start engine and allow to idle. Measure voltage between J7 (B-) and J10 (SPOUT). If voltage is 3.0-8.5 volts, replace ICM. If voltage is not 3.0-8.5 volts, turn ignition off. Disconnect PCM wiring harness connector.
4. Disconnect diagnostic connector from ICM, Leave ICM wiring harness connector connected to diagnostic cable. Measure resistance between J10 (SPOUT) at breakout box and terminal No. 36 (SPOUT) at PCM wiring harness connector. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in SPOUT circuit between PCM and ICM wiring harness connector.

EI SYSTEM (LOW DATA RATE) (MUSTANG 2.3L)

Note. Start all diagnostics with QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. These tests are dependent on results and service codes received during QUICK TEST. DO NOT connect PCM to EI diagnostic cable. If PCM is connected to EI diagnostic cable, PCM may be damaged. PCM 60-pin harness connector may be connected to an additional breakout box only.

Note. Refer to Figs. (Scheme 176) -17 when using pinpoint test procedures.

Perform following checks

1. Inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly routed and securely attached.
2. Check all wiring harness connectors for damaged pins and loose or broken conditions.
3. Ensure ICM mounting screws are tight.
4. Ensure battery is fully charged.
5. Ensure all accessories are off during diagnosis.

Following test equipment is necessary to complete ICM ignition system tests.

1. EI (Low Data Rate) Diagnostic Cable (007-00044)
2. Spark Tester (D81P-6666-A & D89P-6666-A)
3. Digital Volt-Ohmmeter (DVOM)
4. Remote Starter Switch
5. 2 EEC-IV Breakout Boxes (T83L-50-EEC-IV)
6. EEC-IV Breakout Box 2.3L Overlay
7. ICM Adapter Tachometer (007-00061)
8. Inductive Type Timing Light (DO NOT use advance knob, if equipped, as it will not work correctly with EI ignition systems.)
9. 12-Volt Test Light (Incandescent Type)
10. Test Light (LED Type) Or Logic Probe (LED Type)
11. ICM Tester (007-00071)
12. ICM Coil/Sensor Tester (007-00072)

Note. A 12-volt incandescent test light should not be used to test CID, IDM, PIP or SPOUT circuit signals. It will load circuit and may cause incorrect measurements or faulty ICM/PCM operation.

PINPOINT TEST A is intended to diagnose no-start conditions. PINPOINT TESTS B through F are intended to diagnose hard faults. Intermittent failures may be difficult to diagnose using these procedures.

EEC-IV Breakout Box (T83L-50-EEC-IV) connected to EI (Low Data Rate) Diagnostic Cable (007-00044) is referred to as breakout box. If a second breakout box is connected to PCM wiring harness connector, it will be referred to as second breakout box. This setup allows testing of ignition components and wiring harness circuits.

Circuits are identified in all capitals, for example: PIP. Manufacturer's breakout box overlay test terminals are identified by a "J" prefix, for example: J31 (PIP). This indicates test terminal number and circuit identification.

When the letter "I" follows the circuit identification, it implies circuit at ICM for example: J31 (PIP I). When the letter "S" follows the circuit identification, it implies circuit at Crankshaft Position (CKP) sensor for example: J33 (PIP S).

Note. All ignition voltage and resistance tests are performed at breakout box connected to diagnostic cable unless otherwise specified.

2.3L EI PINPOINT TEST INDEX

EI (Low Data Rate) Component Locations (Mustang 2.3L). Scheme 176

Low Data Rate - Diagnostic Cable (Mustang 2.3L). Scheme 177

Ignition System Pin Voltage Chart (Mustang 2.3L). Scheme 178

Ignition System Connector Terminal (Mustang 2.3L). Scheme 179

Ignition System Wiring Diagram (Mustang 2.3L). Scheme 180

ICM Signal Diagram (Mustang 2.3L). Scheme 181

PINPOINT TEST A

PINPOINT TEST B: CODE 222

PINPOINT TEST C: CODE 218

PINPOINT TEST D: CODE 224

PINPOINT TEST E: CODE 213 SPOUT CIRCUIT SHORTED OR OPEN

PINPOINT TEST F: CODE 213/412 OR NO CODES & LACK OF POWER

EI SYSTEM (LOW DATA RATE) (3.0L SHO, 3.2L & 3.8L SC)

Note. Start all diagnostics with QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. These tests are dependent on results and service codes received during QUICK TEST.

Note. Refer to Figs. (Scheme 182) -25 when using pinpoint test procedures.

Perform following checks

1. Inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly routed and securely attached.
2. Check all wiring harness connectors for damaged pins and loose or broken conditions.
3. Ensure ICM mounting screws are tight.
4. Ensure battery is fully charged.
5. Ensure all accessories are off during diagnosis.

Following test equipment is necessary to complete EI system tests.

1. EI Diagnostic Cable (Rotunda 007-00044)
2. Spark Tester (D89P-6666-A)
3. Digital Volt-Ohmmeter (DVOM)
4. Remote Starter Switch
5. 2 Breakout Boxes (T83L-50-EEC-IV)
6. High Voltage Spark Tester (A spark plug with a broken side electrode is not sufficient to check for spark and may lead to incorrect results.)
7. Tachometer
8. Tachometer Adapter (Rotunda 007-00061)
9. Incandescent 12-Volt Test Light
10. Inductive Type Timing Light
11. EI Module Tester (007-00071, If Available)
12. EI Sensor/Coil Tester (007-00072, If Available)

Note. A 12-volt incandescent (high voltage) test light should not be used to test CID, IDM, PIP or SPOUT circuit signals.

PINPOINT TEST A is designed for a no-start condition. PINPOINT TESTS B through E are designed to identify hard faults. PINPOINT TESTS F and G are used to search for intermittent failures. Following information should be noted during testing

1. All voltage readings given in test procedures are based on values obtained using a standard DVOM such as Rotunda (007-00001) or Fluke (20 series, 70 series or 88). DO NOT use RMS type meter.
2. When instructed to inspect a wiring harness, perform both a visual inspection and a continuity test.
3. When making voltage checks, ground connections should be made at negative battery terminal or cast iron surface of engine.
4. When making voltage checks, ground readings are defined as a value of less than 1.0 volt. Battery voltage is defined as a value of 10-14 volts.
5. Circuits are identified in all capitals, for example: PIP. Manufacturer's breakout box overlay test terminals are identified by a J prefix, for example: J31 (PIP). This indicates test terminal number and circuit identification. When the letter "I" follows the circuit identification, it implies PIP circuit at ICM for example: J31 (PIP I). When the letter "S" follows the circuit identification, it implies PIP circuit at ICM for example: J33 (PIP S).
6. Test procedures are intended to identify faulty components or wiring while fault is present. If complaint is an intermittent condition, refer to H - EEC-IV TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

3.0L SHO & 3.8L SC EI PINPOINT TEST INDEX

EI Diagnostic Cable (3.0L SHO, 3.2L & 3.8L SC). Scheme 182

ICM Terminals (3.0L SHO, 3.2L & 3.8L SC). Scheme 183

EI System Pin Voltage Chart (3.0L SHO, 3.2L & 3.8L SC). Scheme 184

EI System Connector Terminal (3.0L SHO & 3.2L). Scheme 185

EI System Connector Terminal (3.8L SC). Scheme 186

EI Signal Diagram (3.0L SHO, 3.2L & 3.8L SC). Scheme 187

EI Circuits (3.0L SHO, 3.2L & 3.8L SC). Scheme 188

PINPOINT TEST B: CODE 212

PINPOINT TEST C: CODE 214

PINPOINT TEST D: CODE 215, 216 OR 217

PINPOINT TEST E: CODE 49 OR 213

Viewing Ignition System Secondary Display

Connect engine analyzer to view parade display of ignition system secondary. While slowly increasing engine speed from idle to 2000 RPM, compare engine analyzer display to illustrations. (Scheme 188) Illustrations shown are for a 4-cylinder engine but are typical for all EI engines.

1. An engine analyzer is used to diagnose problems in secondary side of ignition system.
2. Visually inspect engine compartment to ensure vacuum hoses and spark plug wires are properly routed and securely connected.
3. Examine all wiring harnesses and connectors for insulation damage and burned, overheated, loose and broken conditions.
4. Ensure battery is fully charged and all accessories are turned off during testing.
5. Use an engine analyzer or lab scope and EI Adapter (Rotunda 007-00044) in these testing procedures.

Note. To provide accurate results, maintaining engine analyzer calibration is essential. Refer to equipment manual. If manual is not available, an estimate of calibration can be made by connecting Spark Tester (D81P-6666-A) to a properly operating ignition system and measuring firing voltage of spark tester. Spark tester firing voltage should be approximately 28 k/volts. DO NOT include firing voltage of rotor-to-cap gap.

Identifying EI Secondary Voltage Scope Patterns. Scheme 189

PINPOINT TEST G

EI SYSTEM (HIGH DATA RATE) - (ESCORT 1.9L & TRACER 1.9L)

Note. Start all diagnostics with QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section before entering this test. These tests are dependent on results and service codes received during QUICK TEST.

Note. EI Diagnostic Cable (Rotunda 007-00059) should be used to diagnose this system. This cable is equipped with additional circuits and components used to enhance and modify signals for testing purposes. If an aftermarket test cable is used or diagnosis is being performed using only a DVOM, become familiar with system wiring diagram and system operation.

Note. Refer to Figs. (Scheme 190) -31 when using pinpoint test procedures.

Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly connected. Examine all wiring harnesses and connectors for damaged insulation, burned, overheated or damaged pins, and loose or broken conditions. Check sensor shield connector. Ensure ICM mounting screw is tight. Ensure battery is fully charged and all accessories are off during diagnosis.

Following equipment should be used in these test procedures.

1. EI Diagnostic Cable (Rotunda 007-00059)
2. Spark Tester (Neon Bulb Type)
3. Volt-Ohmmeter (Rotunda 007-00001)
4. Remote Starter Switch
5. 2 Breakout Boxes (T83L-50-EEC-IV)
6. Spark Tester (D81P-6666-A)
7. Inductive Timing Light
8. Test Light (Led Type) Or Logic Probe (Led Type)

Following information should be noted during testing

1. When making measurements on a wiring harness, perform both a visual inspection and a continuity test. Inspect terminal connector pins for damage and corrosion when directed to remove a connector.
2. When checking voltage drop to GROUND, circuit must have a voltage drop of less than 1.0 volt.
3. Battery voltage, COIL PWR or VPWR is any voltage reading within 2 volts of actual battery voltage.
4. Spark timing will vary at idle due to feedback spark strategy used to control idle speed.
5. DO NOT connect positive lead of diagnostic cable or CKP-CKP sensor tee until directed to do so.
6. DO NOT connect use incandescent light to test CKP+, CKP-, IDM, PIP or SPOUT circuits.
7. EEC-IV Breakout Box (T83L-50-EEC-IV) connected to EI diagnostic cable is referred to as breakout box. If a second breakout box is connected to PCM wiring harness connector, it will be referred to as second breakout box. This setup allows testing of ignition components and wiring harness circuits. Circuits are identified in all capitals, for example: PIP. Manufacturer's breakout box overlay test terminals are identified by a "J" prefix, for example: J31 (PIP). This indicates test terminal number and circuit identification. When the letter "I" follows the circuit identification, it implies circuit at ICM for example: J31 (PIP I). When the letter "S" follows the circuit identification, it implies circuit at Crankshaft Position (CKP) sensor for example: J33 (PIP S).

1.9L EI PINPOINT TEST INDEX

EI Diagnostic Cable Diagram (1.9L). Scheme 190

Identifying EI Circuits (1.9L). Scheme 191

EI System Connector Terminal & Component ID (1.9L). Scheme 192

ICM Pin Voltage Chart (1.9L). Scheme 193

EI Signal Diagram (1.9L). Scheme 194

Note. Steps in pinpoint tests are designed to correct one ignition failure at a time. When a component is replaced or service is completed, remove all test equipment. Reconnect all components, and perform QUICK TEST. See G - EEC-IV TESTS W/ CODES article in the ENGINE PERFORMANCE Section.

PINPOINT TEST C: CODE 213, LACK OF POWER OR POOR FUEL ECONOMY

PINPOINT TEST D: CODE 215 OR 216

EI SYSTEM (HIGH DATA RATE) (3.0L FLEXIBLE FUEL)

Note. Start all diagnostics with QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. These tests are dependent on results and service codes received during QUICK TEST.

Note. EI Diagnostic Cable (Rotunda 007-00059) should be used to diagnose this system. This cable is equipped with additional circuits and components used to enhance and modify signals for testing purposes. If an aftermarket test cable is used or diagnosis is being performed using only a DVOM, become familiar with system wiring diagram and system operation.

Note. Refer to Figs. (Scheme 195) -36 when using pinpoint test procedures.

Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly connected. Examine all wiring harnesses and connectors for damaged insulation, burned, overheated or damaged pins and loose or broken conditions. Check sensor shield connector. Ensure Ignition Control Module (ICM) mounting screws are tight and battery is fully charged. All accessories should be off during diagnosis.

Following equipment should be used in these test procedures.

1. EI Diagnostic Cable (Rotunda 007-00059)
2. Spark Tester (Neon Bulb Type)
3. Volt-Ohmmeter (Rotunda 007-00001)
4. Remote Starter Switch
5. 2 Breakout Boxes (T83L-50-EEC-IV)
6. Spark Tester (D81P-6666-A)
7. Inductive Timing Light (EI Compatible)
8. Test Light (LED Type) Or Logic Probe (LED Type)

Circuits are identified in all capital letters (acronyms). For example, Profile Ignition Pickup is identified as PIP. Manufacturer's breakout box overlay test terminals are identified by a "J" prefix. For example, J31 (PIP). The J31 indicates that the measurement is to be taken at terminal No. 31 at the breakout box. The (PIP) indicates that the Profile Ignition Pickup circuit is being checked.

When the letter "I" follows the circuit identification, it implies that the measurement is being taken at the ICM. For example, J31 (PIP I). The (PIP I) implies that the measurement is of the PIP circuit at the ICM. When the letter "S" follows the circuit identification, it implies that the measurement is being taken at the CKP sensor. For example, J32 (CKP+ S). The (CKP+ S) implies that the measurement is of the CKP sensor positive circuit at the CKP sensor.

When the letter "C" follows the circuit identification, it implies that the measurement is being taken at the coil. For example, J10 (C3C). The (C3C) implies that the measurement is of the C3 circuit at the coil pack.

The following information should also be noted during testing

1. When checking a wiring harness, perform both a visual inspection and a continuity test. Inspect terminal connector pins for damage, bending, spreading and corrosion when directed to remove a connector.
2. Spark timing adjustments are not possible. Timing is controlled by ICM with input from PCM.
3. When checking voltage drop to GROUND, circuit must have a voltage drop of less than one volt.
4. Battery voltage (VBAT) is any voltage reading within 2 volts of actual battery voltage.
5. EEC-IV Breakout Box (T83L-50-EEC-IV) connected to EI diagnostic cable is referred to as breakout box or EI breakout box. If a second breakout box is connected to PCM wiring harness connector, it will be referred to as second or PCM breakout box. This setup allows testing of EI components and wiring harness circuits.

Note. A 12-volt incandescent (high voltage) test light should not be used to test circuit signals. It will load circuit and may cause incorrect measurements or faulty EI/PCM operation (engine stall).

3.0L FLEXIBLE FUEL EI PINPOINT TEST INDEX

EI Diagnostic Cable Diagram (3.0L Flexible Fuel). Scheme 195

EI Wiring Diagram (3.0L Flexible Fuel). Scheme 196

EI System Pin Voltage Chart (3.0L Flexible Fuel). Scheme 197

EI Signal Diagram (3.0L Flexible Fuel). Scheme 198

EI Block Diagram (3.0L Flexible Fuel). Scheme 199

PINPOINT TEST B: CODE 212 OR 226

Check Base Timing

PINPOINT TEST D: CODE 215, 216, 217 OR 232

EI SYSTEM (HIGH DATA RATE - 4.6L)

Note. Start all diagnostics with QUICK TEST. See G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. These tests are dependent on results and service codes received during QUICK TEST.

Note. EI Diagnostic Cable (Rotunda 007-00059) should be used to diagnose this system. This cable is equipped with additional circuits and components used to enhance and modify signals for testing purposes. If an aftermarket test cable is used or diagnosis is being performed using only a DVOM, become familiar with system wiring diagram and system operation.

Note. Refer to Figs. (Scheme 200) -41 when using pinpoint test procedures.

Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly connected. Examine all wiring harnesses and connectors for damaged insulation, burned, overheated or damaged pins and loose or broken conditions. Check sensor shield connector. Ensure Ignition Control Module (ICM) mounting screws are tight and battery is fully charged. All accessories should be off during diagnosis.

Following equipment should be used in these test procedures.

1. EI Diagnostic Cable (Rotunda 007-00059)
2. Spark Tester (Neon Bulb Type)
3. Volt-Ohmmeter (Rotunda 007-00001)
4. Remote Starter Switch
5. 2 Breakout Boxes (T83L-50-EEC-IV)
6. Spark Tester (D81P-6666-A)
7. Inductive Timing Light
8. Test Light (LED Type) Or Logic Probe (LED Type)

Circuits are identified in all capital letters (acronyms). For example, Profile Ignition Pickup is identified as PIP. Manufacturer's breakout box overlay test terminals are identified by a "J" prefix. For example, J31 (PIP). The J31 indicates that the measurement is to be taken at terminal No. 31 at the breakout box. The (PIP) indicates that the Profile Ignition Pickup circuit is being checked.

When the letter "I" follows the circuit identification, it implies that the measurement is being taken at the ICM. For example, J31 (PIP I). The (PIP I) implies that the measurement is of the PIP circuit at the ICM.

When the letter "S" follows the circuit identification, it implies that the measurement is being taken at the CKP sensor. For example, J32 (CKP+ S). The (CKP+ S) implies that the measurement is of the CKP sensor positive circuit at the CKP sensor. When the letter "C" follows the circuit identification, it implies that the measurement is being taken at the coil. For example, J10 (LC3C). The (LC3C) implies that the measurement is of the C3 circuit at the left coil pack.

The following information should also be noted during testing

1. When checking a wiring harness, perform both a visual inspection and a continuity test. Inspect terminal connector pins for damage, bending, spreading and corrosion when directed to remove a connector.
2. Spark timing adjustments are not possible. Timing is controlled by ICM with input from PCM.
3. When checking voltage drop to GROUND, circuit must have a voltage drop of less than one volt.
4. Battery voltage (VBAT) is any voltage reading within 2 volts of actual battery voltage.
5. EEC-IV Breakout Box (T83L-50-EEC-IV) connected to EI diagnostic cable is referred to as breakout box or EI breakout box. If a second breakout box is connected to PCM wiring harness connector, it will be referred to as second or PCM breakout box. This setup allows testing of EI components and wiring harness circuits.

Note. A 12-volt incandescent (high voltage) test light should not be used to test circuit signals. It will load circuit and may cause incorrect measurements or faulty EI/PCM operation (engine stall).

4.6L EI PINPOINT TEST INDEX

EI Diagnostic Cable Diagram (4.6L). Scheme 200

EI Wiring Diagram (4.6L). Scheme 201

EI System Pin Voltage Chart (4.6L). Scheme 202

EI Signal Diagram (4.6L). Scheme 203

EI Block Diagram (4.6L). Scheme 204

PINPOINT TEST D: CODE 215, 216, 217 OR 238

Air Supply Pump

Check belt tension, and adjust if necessary. Disconnect air supply hose from by-pass control valve. Start engine. If airflow is felt at pump outlet and increases as engine speed is increased, pump is okay. If airflow is not felt at pump outlet and/or does not increase as engine speed is increased, replace air supply pump.

Air Silencer/Filter (Air Pump & Pulse Air Inlet)

Inspect hoses and air silencer for leaks. Disconnect hose from air silencer outlet. Remove silencer from vehicle, and visually inspect it for plugging. If no plugging or leaks are found, silencer is okay. If any plugging or leaks are found, repair or replace as necessary.

1. Disconnect air supply hose at valve outlet. see scheme 42 Remove vacuum line from vacuum nipple. Ensure vacuum exists at vacuum line before proceeding. see scheme 42: Identifying Normally Closed Air By-Pass Valve
2. Reconnect vacuum line to vacuum nipple. With engine speed at 1500 RPM, air pump supply air should be heard and felt at air by-pass valve outlet.
3. With engine speed still at 1500 RPM, disconnect vacuum line. Air at outlet should decrease significantly or shut off. Air pump supply air should now be heard or felt at silencer ports or at dump port.
4. If normally closed air by-pass valve does not perform as described in steps 2) and 3), check air pump for faults. If air pump is operating satisfactorily, replace air by-pass valve.

Air Check Valve

1. Visually inspect thermactor hoses, tubes, control valves and check valves for leaks which may be due to backflow of exhaust gases. If holes are found and/or traces of exhaust gas products are present, replace check valve.
2. Check valve should allow free flow of air in direction of arrow only. (Scheme 205) Valves should check or block free flow of exhaust gas air in opposite direction.
3. If air does not flow as indicated or if exhaust gas backflows opposite of direction of arrow in illustration, replace check valve.

Testing Air Check Valve. Scheme 205

Air Control Solenoid Valve(s)

Remove connector, and check resistance at solenoid terminals. Resistance should be 50-100 ohms when checked at coil terminals. If resistance is not 50-100 ohms, solenoid should be replaced. For additional circuit test procedures, see CIRCUIT TEST KC in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Air Supply Control Valve

1. Disconnect air supply hose at inlet. Accelerate engine speed to 1500 RPM, and verify presence of airflow in hose. Reconnect air supply hose to valve inlet.
2. Disconnect air supply hoses at outlets "A" and "B". (Scheme 206) Remove vacuum line at vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "B" with little or no airflow at outlet "A".
3. Attach a hose from manifold vacuum fitting to air supply control valve vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "A" with little or no airflow at outlet "B".
4. If valve does not meet above conditions, replace valve. If airflow operates as described in steps 1)-3), valve is okay. Reinstall hoses and clamps.

Air Supply Control Valve. Scheme 206

Air Control Valve (Switch-Relief)

1. Disconnect air supply hose at inlet. Accelerate engine speed to 1500 RPM, and verify presence of airflow in hose. Reconnect air supply hose to valve inlet.
2. Carefully disconnect air supply hoses at outlets "A" and "B". (Scheme 207) Carefully remove vacuum line at vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "B" with little or no airflow at outlet "A".
3. Connect a vacuum line from manifold vacuum fitting to air control valve vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "A" with little or no airflow at outlet "B".
4. If conditions in steps 2) and 3) are not met, replace air control valve. If valve operates satisfactorily, air control valve is okay.

Identifying Air Control Valve (Switch-Relief). Scheme 207

Air Pump Resonator

Visually inspect for holes. Remove hoses, and check for restricted ports. Replace resonator if holes exist or ports are restricted. Reconnect hoses, and install clamps.

1. Disconnect hoses from outlets "A" and "B". see scheme 46 Disconnect and plug vacuum line to port "D". With engine operating at 1500 RPM, airflow should come out of by-pass vents. see scheme 46: Identifying Combination Air By-Pass/Air Control Valve
2. Reconnect vacuum line to port "D". Disconnect and plug vacuum line to port "S". Ensure vacuum is present in line to vacuum port "D". Accelerate engine speed to 1500 RPM. Airflow should come out of outlet "B". Airflow should not be detected at outlet "A".
3. Apply 8-10 in. Hg vacuum to port "S". With engine operating at 1500 RPM, airflow should come out of outlet "A". If valve is bleed-type, less air will flow from outlet "A" or "B" and main discharge will change when vacuum is applied to port "S".
4. If conditions in previous steps are not met, replace valve. If above conditions are met, valve is okay. Reconnect hoses and vacuum lines.

Thermactor Idle Vacuum (TIV) Valve

1. With engine at idle and transmission in Neutral, apply vacuum to small nipple and place fingers over TIV valve atmospheric vent holes. (Scheme 208) If vacuum is not sensed, TIV is damaged and must be replaced. If vacuum is sensed, go to next step.
2. With engine still at idle, use a vacuum pump to apply vacuum to TIV valve large nipple. See TIV VALVE (LARGE NIPPLE) VACUUM SPECIFICATIONS table. If vacuum is not held, TIV is damaged and must be replaced.

Identifying Thermactor Idle Vacuum (TIV) Valve. Scheme 208

TIV VALVE (LARGE NIPPLE) VACUUM SPECIFICATIONS

Vacuum Control Valve (VCV)

1. A 2-port valve may be in open or closed position when engine is cold, but should reverse when engine is warmed to operating temperature.
2. For 3-port valves, passage "A" to "B" should be closed and passage "A" to "C" should be open with a cold engine. (Scheme 209) With engine at normal operating temperature, VCV should be open between "A" and "B" and closed between "A" and "C".
3. For 4-port valve, check "A1" to "B1" and "A2" to "B2" separately. (Scheme 209) A 4-port valve may be in open or closed position when engine is cold, but should reverse when engine is warmed to operating temperature. If these conditions are not met, replace valve.

Identifying Vacuum Control Valves. Scheme 209

Electrical Vacuum Control Valve

1. Electrical vacuum control valve may be either open or closed at room temperature, but should reverse position when engine is at normal operating temperature. While engine is cold, check for continuity across switch terminals. (Scheme 210) Note if switch is open or closed.
2. Warm engine to normal operating temperature. Check for continuity across switch terminals again. Continuity should be opposite of cold condition. If continuity does not switch, replace valve. Check vacuum function of valve. See VACUUM CONTROL VALVE (VCV) test.

Identifying Electrical Vacuum Control Valve. Scheme 210

Vacuum Check Valve

Apply 16 in. Hg vacuum to check valve. If vacuum remains greater than 15 in. Hg for 10 seconds, valve operation is normal. If vacuum drops faster, replace valve.

Vacuum Reservoir

When charged with 15-20 in. Hg vacuum, vacuum loss should not exceed 0.5 in. Hg in 60 seconds. If vacuum loss is faster, replace reservoir.

Pulse Air Valve

With engine at normal operating temperature and at curb idle, remove inlet hose from valve. Suction should be felt at valve inlet. If suction is not felt, replace valve.

Electronic EGR (EEGR) Valve & Pressure Feedback Elec. (PFE)

1. Ensure all vacuum hoses are correctly routed and securely attached. Replace any crimped or broken hoses. Ensure less than one in. Hg vacuum to EGR valve exists at idle with engine at normal operating temperature. NOTE: EVR solenoid has a continuous internal leak which produces a vacuum signal of less than one in. Hg vacuum at idle.
2. Install tachometer. Disconnect idle air by-pass valve electrical connector (if equipped). Remove and plug vacuum hose at EGR valve. Start engine, and idle it in Neutral. Note idle speed. Using vacuum pump, apply 5-10 in. Hg vacuum to EGR valve. When vacuum is fully applied to EGR valve, one or more of following should occur: Engine should stall. Idle speed should drop more than 100 RPM. Idle speed should return to normal when vacuum is released.
3. Repair or replace EGR valve if engine does not respond as specified. Reconnect idle air by-pass valve electrical connector. Unplug and reconnect vacuum hose at EGR valve.

EGR Vacuum Regulator (EVR)

Faults in EVR or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DN in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for diagnostic procedures.

Remove EGR solenoid harness connector. Measure resistance across solenoid terminals. Resistance should be 65-110 ohms. Set DVOM to 200-k/ohm scale. Measure resistance between each solenoid terminal and ground or side of solenoid. Resistance should be greater than 10 k/ohms. If resistance is not as specified in either test, replace solenoid.

Delta Pressure Feedback Electronic (DPFE) EGR Transducer

Faults in DPFE transducer or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, see CIRCUIT TEST DL in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section diagnostic procedures.

Pressure Feedback Electronic (PFE) EGR Transducer

Faults in PFE transducer or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If no service code has been set, see CIRCUIT TEST DL in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for diagnostic procedures.

Apply 16 in. Hg vacuum to check side of valve, and trap. If vacuum remains greater than 15 in. Hg for 10 seconds, valve operation is normal. If vacuum does not remain greater than 15 in. Hg for 10 seconds, replace valve.

When charged with 15-20 in. Hg vacuum, vacuum loss should not exceed 0.5 in. Hg in 60 seconds. If vacuum loss exceeds 0.5 in. Hg in 60 seconds, replace reservoir.

Canister Purge Regulator (CPR) Valve

With CPR valve de-energized, apply 17 in. Hg vacuum to source port. Valve should not pass air. Apply 9-14 volts to one electrical terminal, and ground other. Valve should open and pass air. If valve does not operate as described, replace valve.

Faults in CANP solenoid or circuit should set a service code. See QUICK TEST in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section. If service code has not been set, see CIRCUIT TEST KD in G - EEC-IV TESTS W/CODES article in the ENGINE PERFORMANCE Section for diagnostic procedures.

EVAP Canister

Canister does not have any moving parts. Check for loose, missing, cracked or broken connections and parts. Repair or replace as necessary. Canister should not contain any liquid.

PCV Valve

1. Remove PCV valve from rocker cover grommet. Shake valve. Valve should rattle when shaken. If valve does not rattle, replace valve.
2. Start engine, and warm it to normal operating temperature. On 2.3L HSC, remove corrugated hose from oil separator nipple. Place stiff piece of paper over nipple end, and wait 60 seconds. Vacuum should hold paper in place. If vacuum does not hold paper in place, replace valve.
3. On all other models, disconnect hose from remote air cleaner or outlet tube. Place stiff piece of paper over hose end, and wait 60 seconds. Vacuum should hold paper in place. If vacuum does not hold paper in place, replace valve.

See also:
• FUEL PRESSURE SPECIFICATIONS