Engine Controls - Tests W/codes - Eec-Iv: Other Ford Bronco V

SERVICE CODES

Bronco models use 3-digit codes. When CIRCUIT TEST procedures apply to both 2-digit codes and 3-digit codes, the applicable codes will be separated by a diagonal mark (example: Code 97/631).

During QUICK TEST, 3 types of service codes are retrieved: KOEO, KOER and Continuous Memory codes. See QUICK TEST for self-test procedures. Codes may be cleared from PCM memory after they have been recorded or repaired. See CLEARING CODES .

KOEO & KOER Codes (Hard Faults)

These codes indicate faults are present at time of testing. A hard fault may cause CHECK ENGINE or Malfunction Indicator Light (MIL) to go on and remain on until fault is repaired. If KOEO or KOER codes are retrieved during KOEO SELF-TEST or KOER SELF-TEST, refer to the SERVICE CODE REFERENCE CHARTS to find correct testing and repair procedures.

Continuous Memory Codes (Soft Faults)

These codes indicate a fault that may or may not be present at time of testing. These codes are used to diagnose intermittent problems. Continuous Memory Codes are retrieved after KOEO SELF-TEST. Some codes may turn on MIL/CHECK ENGINE light. Corresponding soft fault trouble code will be retained in PCM memory. If fault does not reoccur within 40 warm-up cycles (80 cycles on some models), PCM will automatically clear code or technician may clear service codes from memory. See CLEARING CODES. Intermittent faults may be caused by a sensor, connector or wiring-related problem. See INTERMITTENTS in TESTS W/O CODES article in this section.

RETRIEVING CODES

Service codes are retrieved from EEC-IV system through Data Link Connector (DLC). Various methods and test equipment may be used to access these codes

1. Analog Volt-Ohmmeter (VOM).
2. Scan tester.
3. In-Dash Malfunction Indicator Light (MIL)/CHECK ENGINE light.

DATA LINK CONNECTOR (DLC) LOCATIONS

Separator Code

Single 1/2-second separator pulse is issued 6-9 seconds after last KOEO code. Continuous Memory Codes (soft faults) are then displayed 6-9 seconds after 1/2-second separator code. Some digital test equipment may display separator code as "10" instead of "1".

Pass Codes

Code 11 or 111 indicates system passes that portion of test. If Code 11 or 111 is not retrieved in KOEO SELF-TEST, codes retrieved during KOER SELF-TEST may not be valid. Code 11-1-11 or 111-1-111, output during KOEO SELF-TEST, indicates no KOEO code or Continuous Memory Code was recorded.

Continuous Memory Codes

Continuous Memory Codes are displayed after separator pulse code in KOEO SELF-TEST. These codes result from information stored by PCM during continuous self-test monitoring. These codes indicate faults recorded within last 40 engine starts (80 engine starts on some models). Fault may or may not be currently present. Refer to the SERVICE CODE DEFINITION CHARTS . Use these codes for diagnosis only when KOEO SELF-TEST and KOER SELF-TEST result in Code 11 or 111.

Fast Codes

At start of KOEO SELF-TEST and after Wide Open Throttle (WOT) request in KOER SELF-TEST, PCM outputs short bursts of information, known as FAST CODES, which were used by manufacturer during assembly. With most equipment, these code bursts are not visible; an entire code sequence lasts less than 1/2 second. If this fluctuation is visible on test equipment, ignore it.

Scheme 66

CLEARING CODES

To clear codes from PCM memory, start KOEO SELF-TEST. When service codes appear on test equipment or CHECK ENGINE light, disconnect jumper wire from Self-Test Input (STI) connector. If using Star Series Tester, unlatch center button. This procedure erases Continuous Memory Codes from PCM memory. If problem has not been corrected or fault is still present, hard code will immediately be reset in PCM memory.

Note. To clear KAM, disconnect negative battery terminal for at least 5 minutes.

VISUAL CHECK & EQUIPMENT HOOKUP

Complete all steps in BASIC TESTING article in this section before proceeding to self-diagnostic tests. Ensure vacuum hoses and EEC-IV wiring harnesses are properly connected.

Apply parking brake, and place shift lever in Park (A/T) or Neutral (M/T). Block drive wheels. Turn off all electrical loads. Connect appropriate test equipment to vehicle as follows

Analog Volt-Ohmmeter (VOM)

1) Turn ignition switch to OFF position. Set VOM at 0-15V DC range. Connect positive lead of VOM to positive battery terminal.

2) Connect negative VOM lead to Self-Test Output (STO) terminal of self-test connector. (Scheme 67) Connect jumper wire from Self-Test Input (STI) pigtail to signal return terminal of self-test connector. KOEO SELF-TEST will activate when ignition is turned on.

Scan Tester

Follow manufacturer's instructions to hook up equipment and record service codes.

Star Series Tester

Turn ignition switch to OFF position. Connect color-coded adapter cable leads to diagnostic tester. Connect 2service connectors of adapter cable to vehicle self-test connector and STI pigtail connector. Connect timing light. Go to KOEO SELF-TEST.

Scheme 67

Scheme 68

COMPUTED TIMING CHECK

Connect timing light and check ignition timing. See IGNITION TIMING in ADJUSTMENTS article in this section. Perform the following procedure as applicable

1. If ignition timing is not correct, go to CIRCUIT TEST PA. (distributor ignition systems).
2. If engine starts and then stalls, go to CIRCUIT TEST S.
3. If engine will not start, go to CIRCUIT TEST AA.

ADDITIONAL SYSTEM FUNCTIONS

Additional diagnostic system features are available to help diagnose driveability problems and service EEC-IV system.

CHECK ENGINE Light & Malfunction Indicator Light (MIL)

CHECK ENGINE light and MIL are intended to alert driver of certain malfunctions in EEC-IV system.

Light may also be used to retrieve service codes stored in PCM. When hooked up for KOEO SELF-TEST or KOER SELF-TEST, light will display all codes which turn on light during vehicle operation.

If light comes on during vehicle operation, vehicle should be inspected as soon as possible. Immediately turning off engine is not necessary; vehicle can be driven with light on.

If light comes on and then goes off during vehicle operation, a code will be stored in PCM memory as a Continuous Memory Code.

Light should come on when ignition is turned on and go out when engine is started. If hard fault codes are not present, PCM turns out light when it receives a Profile Ignition Pick-Up (PIP) signal. If light does not come on, see CIRCUIT TEST ML.

Output State Check

Output state check is used as an aid for servicing EEC-IV system output actuators. It allows technicians to operate most output actuators on command. This mode is entered from KOEO SELF-TEST after all codes have been retrieved. Leave SELF-TEST activated, and depress throttle to initiate test sequence. Each time throttle is depressed and released, output actuators will change from on to off or off to on.

Failure Mode Effects Management (FMEM), Code 98 Or 998

FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to monitor sensor. If faulty sensor's signals return to normal operating range, PCM will use those signals. A Code 98 or 998 will be displayed when FMEM mode is in effect.

SERVICE CODE DEFINITION CHARTS

2-DIGIT SERVICE CODE DEFINITION CHART

3-DIGIT SERVICE CODE DEFINITION CHART

CIRCUIT TESTS

Note. A breakout box, connected to vehicle harness at PCM, is necessary to perform most circuit tests. References to Test Pin No. found in CIRCUIT TEST steps refer to test terminals on manufacturer breakout box overlay. Circuit diagrams at beginning of each test identify circuit and wire colors.

HOW TO USE CIRCUIT TESTS

1) Ensure all non-EEC-IV related faults found while performing steps in BASIC TESTING article in this section have been corrected. Follow each test step in order until fault is found. When more than one code is retrieved, start with first code displayed.

2) CIRCUIT TESTS ensure electrical circuits are okay before sensors or other components are replaced. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, opens or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with ignition on unless otherwise specified in CIRCUIT TESTS.

3) DO NOT measure voltage or resistance at PCM. DO NOT connect any test light unless specified in testing procedure. All measurements are made by probing rear of connector. Isolate both ends of a circuit and turn ignition off when checking continuity.

4) Disconnect solenoids and switches from harness before measuring continuity and resistance or applying voltage. After each repair, reconnect all component connections and repeat QUICK TEST .

5) An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too high for some items in EEC-IV system. If resistance approaches 5 ohms, always clean suspect connector and coat it with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10,000 ohms to ground, unless stated otherwise in CIRCUIT TEST.

Note. In following tests, circuit diagrams and illustrations are courtesy of Ford Motor Co.

CIRCUIT TESTS are grouped as follows.

1. A-C - No Start & Voltage Tests
2. DA-DS - Input Sensor Tests
3. FD-FF - Additional Input Component Tests
4. G-J - Fuel Control System Tests
5. KA-TG - PCM Output Tests

CIRCUIT TEST INDEX

Preliminary Instructions (A/T)

Record and clear continuous memory codes. Warm engine to normal operating temperature. Place gear selector in Drive. Accelerate hard to 35 MPH and coast down to a stop. Shut off engine. Perform KOEO SELF-TEST. Go to step 1).

Preliminary Instructions (M/T)

Record and clear continuous memory codes. Warm engine to normal operating temperature. Accelerate moderately to 40 MPH. Start in first gear, shifting no higher than second gear. Coast down to idle, and stop. Shut off engine. Perform KOEO SELF-TEST, and record continuous memory codes. Go to step 1).

1) Continuous Memory Code 452 Code 452 indicates PCM detected incorrect output from VSS sometime during vehicle operation. Possible causes for this code are

1. Faulty VSS.
2. Open or shorted circuit.
3. Faulty PCM.

Perform appropriate drive cycle procedure. See PRELIMINARY INSTRUCTIONS (A/T) or PRELIMINARY INSTRUCTIONS (M/T) headings above. Ensure driveability complaint can be verified. If Code 452 is still present or driveability complaint can be verified, go to next step. If code is not present or complaint cannot be verified, the fault cannot be duplicated at this time. Clear codes, and refer to SYMPTOMS in the TESTS W/O CODES article in this section.

2) Check VSS Circuit Continuity Turn ignition off. Disconnect VSS sensor. Remove PCM 60-pin connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Measure resistance between VSS (+) terminal at VSS wiring harness connector and test pin No. 3 at breakout box. Measure resistance between VSS (-) terminal at VSS wiring harness connector and test pin No. 6 at breakout box. If any resistance reading is more than 5 ohms, service open circuit in VSS wiring harness and repeat step 1). If both resistance readings are 5 ohms or less, go to next step.

3) Check VSS Circuits For Shorts To Power Or Ground Turn ignition off. Ensure PCM and VSS are disconnected. Measure resistance between test pin No. 3 and test pins No. 6, 37 and 40 at breakout box. If all readings are more than 500 ohms, go to next step. If any reading is less than 500 ohms, repair short in VSS wiring harness and repeat step 1).

4) Check VSS Resistance Leave ignition off. Disconnect VSS wiring harness connector. Measure resistance across VSS terminals. If reading is not 190-250 ohms, replace VSS and repeat step 1). If resistance is 190-250 ohms, replace PCM and repeat step 1).

Continuous Memory Codes 179, 182, 188 & 191

These codes identify a rich fuel condition resulting in adaptive fuel strategy leaning fuel system to compensate.

1. Code 179 Indicates right or rear HO2S detected a problem and adaptive fuel lean limit has been reached at idle.
2. Code 182 Indicates right or rear HO2S detected a problem and adaptive fuel lean limit has been reached at idle.
3. Code 188 Indicates left or front HO2S detected a problem and adaptive fuel lean limit has been reached.
4. Code 191 Indicates left or front HO2S detected a problem and adaptive fuel lean limit has been reached.

Possible causes for these codes are

1. Incorrect fuel pressure.
2. Faulty fuel injector or circuit.
3. Leaking or restricted air intake.
4. Faulty MAP sensor.
5. Restricted air or fuel filter.

If other codes are present, repair as necessary. If no other codes are present, go to next step.

2) Check Fuel Pressure Release fuel system pressure. With ignition off, install fuel pressure gauge. Ensure manifold vacuum is connected to fuel pressure regulator. Start engine and allow to idle. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel system pressure is not within specification, repair as necessary. See FUEL SYSTEM in SYSTEM/COMPONENT TESTS article in this section. If fuel system pressure is within specification, go to next step.

3) Check System Ability To Hold Fuel Pressure With fuel pressure gauge installed, cycle ignition switch from OFF to ON position 3-4 times to pressurize fuel system ( DO NOT start engine). If fuel pressure remains at specification for 60 seconds, go to next step (MAP/BARO equipped vehicles) or step 6) (all other vehicles). If fuel pressure does not remain at specification for 60 seconds, repair fuel system as necessary. See FUEL SYSTEM in SYSTEM/COMPONENT TESTS article in this section.

4) Check MAP/BARO Frequency Turn ignition off. Connect MAP/BARO tester to MAP/BARO sensor. see scheme 16in CIRCUIT TEST DF. Turn ignition on. If MAP/BARO voltage is within specification, go tostep 5) for MFI equipped vehicles or step 6) for SFI equipped vehicles. See MAP SENSOR VOLTAGE OUTPUT table. If voltage is not within specification, check wiring to MAP/BARO sensor for corrosion and other damage. Repair as necessary. Clear KAM, and repeat QUICK TEST. If wiring is okay, replace MAP/BARO sensor. Clear KAM, and repeat QUICK TEST.

5) Cylinder Balance Test (MFI) Connect a tachometer to engine. Start engine, and run at idle. Disconnect and reconnect injectors individually, noting RPM drop as each injector is disconnected. IAC motor will attempt to re-establish RPM. If each injector produces a momentary drop in RPM, original fault is in ignition system. If each injector does not produce a momentary drop in RPM, go to step 7).

6) Cylinder Balance Test (SFI) Perform KOER SELF-TEST. After last code is displayed, wait 5-10 seconds. Enter CYLINDER BALANCE TEST by lightly goosing throttle (not WOT). Test time is about 2-3 minutes. To interpret codes retrieved from test, refer to CYLINDER BALANCE TEST SERVICE CODES table. If Code 90 is present, original fault is in ignition system. If Code 90 is not present, go to step 8).

CYLINDER BALANCE TEST SERVICE CODES

7) Check Injector & Circuit Resistance (MFI) Turn ignition off. Wait 10 seconds. Disconnect PCM 60-pin connector. Inspect pins for damage. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance of injector bank No. 1 between test pins No. 37 and 58 at breakout box. Measure resistance of injector bank No. 2 between test pins No. 37 and 59 at breakout box. Record resistances. See MFI INJECTOR BANK RESISTANCE table in this circuit test. If each resistance is within specification, go to step 12). If resistance is not as specified, go to step 9).

8) Check Injector & Circuit Resistance (SFI) Turn ignition off and wait 10 seconds. Disconnect PCM 60-pin connector. Inspect pins for damage. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure and record resistance between suspected injector circuit test pin and test pin No. 37. See INDIVIDUAL INJECTOR RESISTANCE table below in this circuit test. If each resistance is within specification, go to step 12). If resistance is not as specified, go to next step.

INDIVIDUAL INJECTOR RESISTANCE (1)

INJECTOR BANK RESISTANCE

9) Check Continuity Of Fuel Injector Circuit Turn ignition off. Disconnect suspect injector wiring harness connector at injector. Measure resistance between test pins No. 37 and 57 at breakout box and each injector VPWR terminal at wiring harness connector. see scheme 27and see scheme 28. Measure resistance between injector test pin(s) at breakout box and same injector circuit terminal at each injector wiring harness connector. If each resistance is less than 5 ohms, go to next step. If each resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST.

10) Check Injector Circuit For Short To Power Or Ground Turn ignition off. With breakout box installed and PCM disconnected, disconnect suspect fuel injector wiring harness connector. Measure resistance between injector test pin(s) and test pins No. 37, 40, 46, 57 and 60. Measure resistance between injector test pin(s) at breakout box and chassis ground. If each resistance is 10,000 ohms or more, replace injector per cylinder balance test service code and repeat QUICK TEST (SFI) or go to next step (MFI). If each resistance is less than 10,000 ohms, repair short. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST .

11) Isolate Faulty Injector Circuit Turn ignition off. With PCM disconnected, disconnect all injectors on suspect bank. Connect one injector and measure resistance between test pin No. 37 and 58 (injector bank No. 1) or between test pin No. 37 and 59 (injector bank No. 2). Disconnect injector, and repeat process for all other injectors. See INDIVIDUAL INJECTOR RESISTANCE table above. If all injectors are within specification, go to next step. If injectors are not as specified, replace injector. Remove breakout box, and reconnect components. Drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST.

12) Check Injector Drive Signal With ignition off, connect PCM to breakout box. Use a non-powered, 12-volt test light, and connect as follows

1. MFI Connect test light between test pins No. 37 and 58 at breakout box. Connect test light between test pins No. 37 and 59 at breakout box.
2. SFI Connect test light between test pin No. 37 and suspect injector test pin at breakout box.

Crank or start engine. If test light glows dimly, system is operating correctly. Clean injectors, and drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST and CYLINDER BALANCE TEST. If test light does not glow dimly (no light/bright light), replace PCM. Reconnect all components, and drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST.

Engine Starts

1. Fuel pump secondary circuit shorted to power.
2. Fuel pump relay contacts always closed.
3. Open FPM circuit between PCM and junction to POWER-TO-PUMP circuit.
4. Left/front HO2S short to power (dual HO2S applications).
5. Faulty PCM.

No Start

1. IFS switch circuit open or not reset.
2. Open circuit in or between PCM and fuel pump.
3. Faulty ground connection at fuel pump.
4. Faulty fuel pump.

If engine starts, go to next step. If engine does not start, go to step 15).

11) Check Fuel Pump Operation Turn ignition on. Wait 5 seconds. Listen for fuel pump operation. If fuel pump is off, go to step 13). If fuel pump is on, go to next step.

12) Check For Fuel Pump Relay Always Closed Turn ignition off. Disconnect fuel pump relay. Turn ignition on. If fuel pump is off with relay disconnected, replace fuel pump relay and repeat QUICK TEST . If fuel pump is on with relay disconnected, repair short to power in POWER-TO-PUMP or FPM circuit. (For models with relay block, also check fuel pump prime plug circuit). Repeat QUICK TEST.

13) Check Continuity Of Fuel Pump Monitor (FPM) Circuit Turn ignition off. Disconnect PCM 60-pin connector. Inspect and repair any damaged terminals. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect fuel pump relay. Measure resistance between test pin No. 8 at breakout box and POWER-TO-PUMP circuit at fuel pump relay wiring harness connector. If resistance is less than 5 ohms, go to step 25) (dual HO2S) or replace PCM and repeat QUICK TEST (single HO2S). If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST.

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 13) to step 15). No test procedures have been omitted.

15) Check Inertia Fuel Shutoff (IFS) Switch Turn ignition off. Disconnect IFS switch. Ensure switch is reset. Measure resistance between IFS switch terminals. If resistance is less than 5 ohms, check for open in POWER-TO-PUMP circuit, poor fuel pump ground or faulty fuel pump. If resistance is 5 ohms or more, reset or replace IFS switch. Repeat QUICK TEST .

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 20). No test procedures have been omitted.

20) Code 543 Code 543 indicates fuel pump secondary circuit failure between B+ circuit and FPM connection to POWER-TO-PUMP circuit. Following are possible causes

1. Open circuit between B+ and FPM connection to POWER-TO-PUMP circuit.
2. Fuel pump relay contacts are always open.

1. HO2S short to power (dual HO2S models).
2. Faulty PCM.

If engine starts, go to step 25) (dual HO2S) or replace PCM and repeat QUICK TEST (single HO2S). If engine does not start, go to next step.

21) Check For B+ To Fuel Pump Relay Turn ignition off. Disconnect fuel pump relay. Measure voltage between B+ terminal at fuel pump relay wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, check fuse/fusible link. If fuse/fusible link is okay, repair open circuit in B+ circuit. Repeat QUICK TEST .

22) Check POWER-TO-PUMP Circuit Continuity Turn ignition off. Leave fuel pump relay disconnected. Measure resistance between POWER-TO-PUMP terminal at fuel pump relay wiring harness connector and negative battery terminal. If resistance is less than 10 ohms, replace fuel pump relay and repeat QUICK TEST. If resistance is 10 ohms or more, repair open circuit in POWER-TO-PUMP circuit between FPM junction and fuel pump relay. Repeat QUICK TEST.

Note. A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 25). No test procedures have been omitted.

SUMMARY

If no service code, Code 11 or 111 (pass code) displays, but driveability problem still exists, go to EEC-IV DIAGNOSIS BY SYMPTOM table. If driveability problem still cannot be located, proceed to the TESTS W/O CODES article for diagnosis by symptoms or intermittent diagnostic procedures.

Wiring Diagram (5.0L Without E40D Or 4R70W - 1 Of 2). Scheme 69

Wiring Diagram (5.0L Without E40D Or 4R70W - 2 Of 2). Scheme 70

Wiring Diagram (5.0L With E40D - 1 Of 2). Scheme 71

Wiring Diagram (5.0L With E40D - 2 Of 2). Scheme 72

Wiring Diagram (5.0L With 4R70W - 1 Of 2). Scheme 73

Wiring Diagram (5.0L With 4R70W - 2 Of 2). Scheme 74

Wiring Diagram (5.8L - 1 Of 2). Scheme 75

Wiring Diagram (5.8L - 2 Of 2). Scheme 76