5.0l/5.8l Feedback Carburetor Tests W/codes Ford Cab & Chassis Ranger

DIAGNOSIS & TESTING

Note. The 5.0L FBC models are for California vehicles that are under 8500 GVW. The 5.8L FBC models are for vehicles that under 8500 GVW High Alt.

DIAGNOSTIC PROCEDURE

The checks, codes and test charts for each engine are in separate sections of this article. Use the directory at the front of the article to locate the correct page. The headings at the top of the pages will also help you find the tests for your engine. Follow this sequence when testing

1. Make sure all NON-EEC problems are solved first. Loose wires, low compression, fouled plugs, etc. can cause problems that waste valuable time.
2. Connect test equipment (as described later in this article) to the engine.
3. Perform «Key On/Engine Off (KOEO) Self-Test»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-onengine-off-koeo-self-test) under READING SELF-TEST CODES for your engine. This checks input and output circuits. If any codes appear, refer to the proper test shown in the reference table for that engine. Start with the first code displayed. If the tests refer you to other checks, perform them as instructed.
4. Perform the Computed Timing Check. This checks the system's spark timing ability.
5. Do the Engine Running Self-Test. This is a system check with sensors and output devices. If any codes appear, refer to the proper test shown in the reference table.
6. To check for intermittent problems, perform the Continuous Self-Test. This monitors the inputs for shorts and open circuits as you wiggle wires and connectors.

PREPARATION FOR TESTING

Correct test results for this system are dependent on the correct operation of several related non-EEC components and systems. All non-EEC problems should be corrected before attempting to diagnose the EEC system.

Before hooking up any equipment to diagnose the EEC system, make the following checks

1. Verify the condition of the air cleaner and air ducting.
2. Check all vacuum hoses for leaks, restrictions and proper routing.
3. Check the EEC system wiring harness electrical connections for loose or detached connectors, wires or terminals, and proper routing.
4. Check the ECA, sensors and actuators for physical damage.
5. Perform all necessary safety precautions to prevent personal injury or vehicle damage.
6. Set parking brake and place shift lever in "Park" (Neutral for manual transmission). DO NOT move shift lever during testing unless specifically directed to do so.
7. Turn off all lights and accessories, and make sure that vehicle doors are closed when making readings.
8. Check coolant level and correct as necessary.
9. Start engine and idle until upper radiator hose is hot and pressurized and throttle is off fast idle. Check for leaks around exhaust manifold, oxygen sensor and vacuum connections
10. Turn ignition off.

Note. If vehicle is towed in or is suspected of having intermittent problems, do not turn the ignition key off. Diagnostic codes may be stored in the continuous testing memory.

READING SELF-TEST CODES

Service codes are transmitted to the Self-Test Output connector. They are shown as voltage pulses on a Volt-Ohmmeter (VOM), or as numbers on the STAR tester.

Key On/Engine Off (KOEO) Self-Test

The first code shown is the On Demand code, the second code is a Separator code and the third code is the Continuous code. The On Demand first digit is indicated by a pulse, then the needle drops to zero for 2 seconds, then the second digit of the code is displayed. After 6-9 seconds, the Separator code (single digit) will be displayed for 1/2 second. After 6-9 seconds, the first digit of the Continuous code will be displayed, the needle will drop to zero for 2 seconds, then the second digit of the Continuous code will display. (Scheme 145)

Engine Running Self-Test

The codes shown are an Engine ID code, a Dynamic Response Code and an On Demand code. On Demand codes are the same as Continuous codes in KEY ON-ENGINE OFF (KOEO) SELF-TEST. Dynamic Response code is the same as a Separator code in KEY ON-ENGINE OFF (KOEO) SELF-TEST. The Engine ID code has no application in the field, and is for factory use only. The codes will be displayed in the same manner as Key On-Engine Off Self Test codes. (Scheme 146)

EQUIPMENT HOOK-UP

With ignition off, connect a timing light to engine. Connect a jumper wire from the Self-Test input to ground. Connect a DC voltmeter (0-20V range) to battery positive terminal and Self-Test output terminal No. 4. (Scheme 144)

Meter Hook-Up for Reading Codes. Scheme 144

TEST EQUIPMENT

The following equipment is recommended to diagnose and test EEC-IV systems. Some equipment is REQUIRED to perform tests. DO NOT attempt to test this system without proper equipment. Damage to vehicle components will result if improper equipment is used.

1. Self-Test Automatic Read-Out (STAR) Tester. This tool is recommended, but not required. It is specially built for the EEC-IV system and is used to display the 2-digit service codes that are programmed into the control module.
2. Analog Volt-Ohmmeter with 0-20V DC range. This can be used as an alternate to the STAR tester.
3. Breakout Box. This is a jumper wire assembly which connects between the vehicle harness and the ECA. The Breakout Box is REQUIRED to perform certain tests on the system. Ford Motor Co. DOES NOT recommend using a DVOM to probe the ECA pins as permanent damage to the pins will result.
4. Digital Volt-Ohmmeter (DVOM) with 10 megohms minimum input impedance.
5. Vacuum Gauge with 0-30 in. Hg range, and resolution in the 1 Hg. range.
6. Tachometer with 0-6000 RPM range, accuracy F 40 RPM and resolution within 20 RPM.
7. Vacuum Pump with 0-25 in. Hg range.
8. Timing light.
9. Spark tester. A modified spark plug with side electrode removed and alligator clip attached may be used.
10. Non-powered test light.
11. Jumper wire about 15" long.

Note. A small, portable tester for 1983-85 models is available from Hickok Electrical Instrument Co., 10514 Dupont Ave., Cleveland, OH 44106. This tester (STAR; Self Test Automatic Readout) provides a built-in capability to locate intermittents within the EEC-IV system.

KEY ON-ENGINE OFF (KOEO) SELF-TEST

Connect voltmeter and insert jumper wire to self-test input terminal and output terminal No. 2. This activates the self-test. Turn ignition switch to "Run" position. DO NOT depress throttle during test. Observe and record On Demand and Continuous codes. When more than 1 code is displayed, always repair problems in the order that codes were displayed. Repair codes as follows

CODE/TEST MENUS (KOEO)

KEY ON-ENGINE OFF (KOEO) SELF-TEST RESULTS

ON DEMAND CODES

Key On-Engine Off (KOEO) Code Format. Scheme 145

TIMING CHECK

Disconnect grounded jumper wire from self-test input. Start engine and reconnect grounded jumper wire to self-test input. Check timing within 2 minutes after display of last code. If timing is 27 33° BTDC, proceed to Engine Running Self-Test. If timing is not 27-33° BTDC, proceed to TEST T - SPARK TIMING CHECK .

Note. If engine stalls while testing, proceed to TEST D - NO/WRONG CODES , step 10).

KEY ON/ENGINE RUNNING (KOER) SELF-TEST

This test checks sensors under actual operating conditions and at normal operating temperature. Any faults must be present at time of test to be detected.

Note. If engine will not start, perform TEST A - NO START .

Connect jumper wire or STAR tester to activate test. This test will display and Engine ID code, a Dynamic Response code, and an On Demand Service code. After a Dynamic Response code (single digit) is received, quickly press and release accelerator once only.

Deactivate the self-test. Start and run engine at more than 2000 RPM for 2 minutes. Turn engine off and wait 10 seconds. Activate self-test. Start engine. Test will proceed with Engine ID code, Dynamic Response code, and Engine Running On Demand Service codes. If a 10 or 1 pulse occurs during Dynamic Response code, open throttle wide open momentarily. Record codes and proceed as follows

Key On-Engine Running (KOER) Code Format. Scheme 146

CODE/TEST MENU (KOER)

KEY ON-ENGINE RUNNING (KOER) SELF-TEST RESULTS

Note. If engine stalls while testing, proceed to TEST D - NO/WRONG CODES , step 10).

CONTINUOUS TEST

1. Codes shown in this test are intermittent service codes. Unless instructed otherwise, do not disconnect any sensor with ignition on, or a service code may be stored.
2. Verify that previous self-tests indicated a pass (code 11). If an On Demand code is detected during this test, repair it first, as some hard failures will set a code in the continuous test.
3. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). When the first service code appears, exit self-test by removing jumper wire from self-test input. This clears ECA of all codes stored in continuous memory. (Scheme 147)
4. Check your list of Continuous codes that were recorded in «Key On/Engine Off (KOEO) Self-Test»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-onengine-off-koeo-self-test) under READING SELF-TEST CODES and Engine Running Self-Test. Disregard any codes you already repaired. To confirm remaining codes, perform Continuous Monitor Test.

Continuous Memory Service Codes STAR tester display is shown. Scheme 147

CONTINUOUS MONITOR (WIGGLE) TEST

Note. Make sure that Self-Test is deactivated. DO NOT activate Self-Test unless specifically instructed to do so.

1. This test monitors ECA inputs for shorts and opens. Self Test output will be activated when a fault is detected. A detected fault is indicated by a 10.5 volt or greater deflection on VOM. One or both of the following modes may be used to find intermittent fault: Key On/Engine Off (KOEO): Self-Test deactivated and ignition switch ON. Key On/Engine Running (KOER): Self-test activated. After service code output has finished, do not turn engine off or deactivate Self-Test. About 2 minutes after code 11 has been displayed, Continuous Monitor test mode will start. It will run until Self-Test is deactivated or engine is turned off. NOTE: An alternate method of entering this test with engine running is to enter Engine Running test, exit, and re-enter Engine Running test. DO NOT turn engine off.
2. Observe VOM while moving, wiggling, and tapping the system harness, connectors, and sensors. If an intermittent condition is created, the monitor will indicate this by storing a service code.
3. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) to retrieve codes. If any codes are indicated, go to proper test as shown in Continuous Test table. If no codes appear, the fault is not in a monitored EEC sensor circuit. EEC testing is complete. Refer to «TEST X - DIAGNOSIS BY SYMPTOM»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-x-diagnosis-by-symptom) for additional testing information.

Note. Continuous test can only be run once without turning ignition off. DO NOT miss any of the service codes.

CODE/TEST MENU (CONTINUOUS)

CONTINUOUS TEST RESULTS

Disconnect grounded jumper wire from self-test input. Start engine and reconnect grounded jumper wire to self-test input. Check timing within 2 minutes after display of last code. If timing is 27 33° BTDC, proceed to Engine Running Self-Test. If timing is not 27-33° BTDC, proceed to TEST T - SPARK TIMING CHECK .

Note. If engine stalls while testing, proceed to TEST D - NO/WRONG CODES , step 10).

HOW TO USE CIRCUIT TESTS

1. DO NOT run any test unless codes have been set. Make sure all non-EEC related faults are corrected. DO NOT replace any parts unless directed to do so. When more than one service code is received, start with lowest code first. NOTE: Procedures in the TESTING section of this article are not in absolute numerical order. Procedures not related to this engine have been removed to eliminate confusion.
2. DO NOT measure voltage or resistance at ECA or connect any test lamps to it, unless specified. All measurements are made by probing the REAR of the connector. Isolate both ends of a circuit and turn ignition off whenever checking for shorts or continuity, unless specified.
3. Disconnect solenoids and switches from harness before measuring continuity, resistance or applying 12 volts. Follow each step in order until fault is found. After any repairs, check all component connections and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .

Output State Test

1. These checks are specified in the testing charts. Output State Test is used to diagnose each actuator. Test is performed in the Key On-Engine Off Self-Test mode, after service codes have been sent. DO NOT disable self-test, but momentarily depress throttle and release. All auxiliary EEC outputs will be activated at this time. Another throttle depression will turn them off.
2. Connect DVOM to self-test output pin 4. Start the Key On Engine Off Self-Test. When Continuous codes are completed, DVOM will read 0 volts. Depress accelerator to turn on actuators.
3. Disconnect DVOM from pin 4 and connect to appropriate actuator. Measure voltage at actuator. Readings above 10.5 volts indicate actuators are on, readings below 2 volts indicate actuators are off. Each test will tell what action to take according to voltage shown on DVOM.

5.0L & 5.8L FBC EEC-IV System Inputs/Outputs and Component Locations. Scheme 148

TEST A - NO START

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuel quantity and quality, ignition system damage, cracks, moisture, etc., engine mechanical conditions such as valves, timing belt, etc. Also included are starter and battery circuit problems.

1. Try to start engine. If engine does not crank, check vehicle starting and charging systems. If engine cranks, but does not start or else stalls after starting, go to next step.
2. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position Sensor (TPS). Turn key on, leaving engine off. Measure voltage at TPS harness connector between voltage reference (VREF) and signal return. If reading is less than 4.0 volts or higher than 6.0 volts, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is between 4.0 and 6.0 volts, reconnect TPS and go to next step.
3. Disconnect any spark plug wire and connect spark tester between plug wire and engine ground. Crank engine and check for spark. If spark exists, connect spark plug wire and go to step 13 . If no spark, connect spark plug wire and go to next step.
4. Remove high tension coil wire from distributor and install spark tester. Check for spark while cranking engine. If spark exists, connect coil wire and service or repair TFI ignition system. If there is no spark, connect coil wire and go to next step.
5. Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale and disconnect TFI. Measure resistance between test pin 16 and TFI harness connector ignition ground. If reading is more than 5 ohms, repair harness and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is less than 5 ohms, go to next step.
6. With breakout box installed and box timing switch on "Distributor" position, connect TFI and ECA. Try to start vehicle. If vehicle starts, go to step 10 . If vehicle does not start, go to next step.
7. Move breakout box timing switch to "Computed" position. Set DVOM on 20-volt scale and measure voltage between test pin 36 and chassis ground while cranking engine. If reading is between 3.0 and 6.0 volts, EEC-IV system is NOT at fault. Diagnose TFI ignition system. If reading is less than 3.0 volts or more than 6.0 volts, go to next step.
8. Turn key off and wait 10 seconds. With breakout box installed, disconnect ECA and TFI. Set DVOM on 200,000-ohm scale and measure resistance between test pin 36 and test pins 16, 20, 26, 40, and 60 for short to ground. Measure resistance between test pin 36 and test pins 37 and 57 for short to power. Measure resistance between test pins 36 and 56 for short to PIP. If any reading is less than 10,000 ohms, repair short in harness and repeat «QUICK TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If engine still does not start, go to next step. If all readings are 10,000 ohms or higher, go to next step.
9. Turn key off and wait 10 seconds. With breakout box installed, connect ECA, but leave TFI disconnected. Set DVOM on 200 ohm scale. Measure resistance between test pin 36 and test pins 37 and 57 for short to power. Measure resistance between test pin 36 and test pins 40 and 60 for short to ground. If any reading is less than 5 ohms, replace ECA and repeat «QUICK TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If all readings are 5 ohms or higher, connect TFI and go to next step.
10. With breakout box installed and DVOM on 20-volt scale, measure voltage between test pin 56 and 16, while cranking engine. If reading is between 3.0 and 6.0 volts, remove breakout box. Replace ECA and repeat «QUICK TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is less than 3.0 volts or more than 6.0 volts, go to next step.
11. Install breakout box, turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect TFI and ECA. Measure resistance between test pin 56 and TFI connector PIP circuit. If reading is 5 ohms or more, repair open PIP circuit and repeat «QUICK TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If readings is less than 5 ohms, go to next step.
12. With breakout box installed and ECA disconnected, turn key off. Disconnect TFI connector and set DVOM on 200,000-ohm scale. Measure resistance between test pin 56 and test pins 16, 20, 26, 40, and 60 for short to ground. Measure resistance between test pin 56 and test pins 37 and 57 for short to power. Measure resistance between test pin 56 and test pin 36 for short to Spark Output (SPOUT). If any reading is less than 10,000 ohms, repair PIP circuit and repeat «QUICK TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If all readings are higher than 10,000 ohms, diagnose TFI ignition system.
13. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged, loose, or corroded pins or wires. Repair wiring as necessary. Install breakout box and connect ECA. Make sure that box timing switch is in "Computed" position. Set DVOM on 20 volt scale and measure voltage between test pin 36 and chassis ground while cranking engine. If reading is between 3.0 and 6.0 volts on fuel injected engines, go to next step. If reading is less than 3.0 volts or more than 6.0 volts, go to step 10 .
14. Disconnect all electrical connections at injectors. Connect pressure gauge to fuel diagnostic valve (if equipped) on fuel rail. Note initial pressure reading. Pressurize fuel system by turning key on for 1 second, turning key off, and then waiting 10 seconds. Repeat on, off, and wait sequence 5 times. Turn key off and wait 10 seconds. Connect all injectors. If pressure increased, go to «TEST II - WOT A/C CUTOFF (WAC) A/C DEMAND»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-ii-wot-ac-cutoff) , step 1) for EFI fuel injected engines. If pressure did not increase, go to next step.
15. With key off and fuel pressure gauge installed, locate fuel pump inertia switch and push button on switch to reset it. If switch will not reset to on, replace inertia switch and repeat step 14 . If switch button was already on, go to «TEST T - SPARK TIMING CHECK»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-t-spark-timing-check) , step 1). Observe pressure gauge as system is pressurized as in step 14 . If pressure reading increases, repeat «QUICK TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If pressure reading does not increase, go to «TEST T - SPARK TIMING CHECK»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-t-spark-timing-check) , step 1).

TFI Module Circuits. Scheme 149

Scheme 150

1. Turn ignition on, engine off. With DVOM on 20 volt scale, measure voltage across battery terminals. If more than 10.5 volts, go to next step. If less than 10.5 volts, service discharged battery.
2. Ignition on, engine off. With DVOM on 20 volt scale, measure voltage between battery negative post to signal return circuit in self-test connector. If less than.5 volts, go to next step. If more than.5 volts, go to step 4.
3. Connect breakout box, ECA connected. Turn ignition on, engine off. With DVOM on 20 volt scale, measure voltage from battery positive post to box pin 37 and pin 57. If both readings are less than.5 volts, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If either is more than.5 volts, go to step 7.
4. With breakout box and ECA connected, turn ignition on (engine off). With DVOM on 20 volt scale, measure voltage from battery negative post to box pin 40 and pin 60. If both readings are less than.5 volts, go to next step. If either is.5 volts or more, circuit has high resistance or open. Correct faulty ground circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
5. With breakout box and ECA connected, place DVOM on 200 ohm scale. Turn ignition off and wait 10 seconds. Measure resistance between box pins 40 and 46, and between box pins 46 and 60. If both readings are less than 5 ohms, go to next step. If either is 5 ohms or more, disconnect ECA connector and inspect for damaged pins and corrosion. Repair as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If fault is still present, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
6. With breakout box and ECA connected, place DVOM on 200 ohm scale. Turn ignition off and wait 10 seconds. Measure resistance between box pin 46 and signal return circuit in self-test connector. If less than 5 ohms, system okay, repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If 5 ohms or greater, excessive resistance in signal return circuit is indicated. Correct fault and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). (Scheme 150): Battery Test Circuits
7. Place DVOM on 20 volts scale. With ECA connected, turn ignition on. Connect DVOM negative lead to battery negative post and make the following voltage checks with DVOM positive lead. Ignition must remain on for these checks. Keep alive power circuit at EEC power relay. If 10.5 volts or greater, continue checks. If less than 10.5 volts, check keep alive power and vehicle power circuits for shorts to ground. Check keep alive power circuit from power relay to battery positive post for opens. Ignition circuit at EEC power relay. If 10.5 volts or greater, continue checks. If less than 10.5 volts, check 10 amp fuse in location 18. Check for opens in ignition switch circuits. Service as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). Ground circuit at EEC power relay. If less than.5 volt, go to next check. If.5 volt or more, correct open or ground in ground circuit. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). Vehicle power circuit at EEC power relay. If 10.5 volts or more, correct short to ground or open in vehicle power circuit from relay to ECA connector pins 37 and 57. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If less than 10.5 volts, replace power relay and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).

Scheme 151

1. Turn ignition off and connect breakout box (ECA connected). Turn ignition on. With DVOM on 20 volt scale, connect positive lead to box pin 37 and negative lead to signal return in self-test connector. If 10.5 volts or greater, go to next step. If less than 10.5 volts, go to «TEST B - VEHICLE BATTERY»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
2. With ignition still on, measure voltage between box pins 26 and 46. If 4-6 volts; reference voltage okay, repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If 4 volts or less, go to step 4. If 6 volts or more, go to next step.
3. Turn ignition off and wait 10 seconds. Disconnect ECA (breakout box connected). Place DVOM on 20 volt scale. Measure voltage from box pin 26, then box pin 46 to battery ground. If less than.5 volt, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If.5 volt or more, service short to battery power in EEC harness. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
4. Turn ignition off and wait 10 seconds. Reconnect ECA to breakout box. Disconnect throttle position sensor (TPS) from vehicle harness. Turn ignition on. With DVOM on 20 volt scale, measure voltage between box pins 26 and 46. If less than.4 volt, go to next step. If.4 volt or more, replace TPS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
5. Turn ignition off and wait 10 seconds. With breakout box and ECA connected, disconnect EGR valve position sensor from harness. Turn ignition on. With DVOM on 20 volt scale, measure voltage between box pins 26 and 46. If less than 4 volts, go to next step. If more than 4 volts, replace EGR valve position sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
6. Turn ignition off and wait 10 seconds. With breakout box and ECA connected, disconnect MAP (manifold absolute pressure) sensor from harness. Turn ignition on and place DVOM on 20 volt scale. Measure voltage between box pins 26 and 46. If less than 4 volts, go to next step. If 4 volts or more, replace MAP sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). (Scheme 151): Reference Voltage Test Circuits
7. With ignition off, disconnect ECA (breakout box connected). Turn ignition off and wait 10 seconds. Disconnect throttle position, barometric pressure and EGR valve position sensors from vehicle harness. With DVOM on 200 ohm scale, measure continuity from box pin 26 to box pins 20, 40, 46 and 60, in turn. If less than 5 ohms, service short to ground in voltage reference circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If 5 ohms or greater, go to next step.
8. With breakout box connected, leave ECA and sensors listed in step 7 disconnected. Turn ignition off. With DVOM on 200 ohm scale, measure continuity on sensors listed in step 7 from box pin 26 to voltage reference circuit on sensor harness connectors. If all readings are less than 5 ohms, reconnect sensors and replace ECA. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If any reading is 5 ohms or greater, repair open in voltage reference circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).

TEST D - NO/WRONG CODES

1. Turn ignition off and wait 10 seconds. Place DVOM on 20 volt scale. Disconnect throttle position sensor (TPS). Turn ignition on. Measure voltage at TPS harness connector between voltage reference signal circuit and signal return circuit. If 6 volts or more, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) , step 2). If less than 4 volts, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) , step 1). If between 4-6 volts, reconnect TPS and go to next step.
2. With ignition on, measure voltage between battery negative post and signal return circuit in Self-Test connector. If less than .5 volt, go to next step. If .5 volt or more, go to «TEST B - VEHICLE BATTERY»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) , step 4)
3. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Repair as required. Connect breakout box and reconnect ECA. Place DVOM on 200 ohm scale. Measure resistance of Self-Test connector from Self-Test pigtail to box pin 48. If less than 5 ohms, go to next step. If 5 ohms or more, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
4. Measure resistance of Self-Test output between Self-Test connector and box pin 17. If less than 5 ohms, go to next step. If 5 ohms or more, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
5. Turn ignition off. Connect DVOM between oxygen sensor ground point on engine and box pin 49. If 5 ohms or more, repair oxygen sensor ground wire or open circuit bad connection and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If less than 5 ohms, disconnect ECA and inspect connector. If okay, reconnect and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If problem still present, replace ECA.
6. Continuous Code 15. Code 15 is recorded any time power is lost to Keep Alive Memory circuit. Clear continuous codes and repeat «Key On/Engine Off (KOEO) Self-Test»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-onengine-off-koeo-self-test) under READING SELF-TEST CODES. If code 15, go to next step. If no code 15, test complete.
7. Ensure EEC components are properly connected and wiring does not contact ignition components or wires. Service as required and repeat «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) under QUICK TESTS. If code 15, go to next step. If no code 15, test complete.
8. Check power circuit to Keep Alive Memory circuit for voltage. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and check connector terminals and ECA pins for damage. Connect breakout box, leaving ECA disconnected. With DVOM on 20 volt scale, connect positive lead to box pin 1 and negative lead to pin 46. Turn ignition on and observe reading. If less than 10 volts, service open to Keep Alive Memory circuit and repeat under «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If 10 volts or more, go to next step.
9. With ignition on, activate «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 15, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no code 15, disconnect breakout box and repeat «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) .
10. Engine Stalls Routine. Perform diagnosis of non-EEC related components and repair as required. Check all vacuum lines, electrical connections and routing. Diagnose engine functions as on a vehicle without EEC. After correcting faults, go to next step.
11. Turn ignition off and wait 10 seconds. Install tachometer. Start engine and attempt to maintain engine at 2000 RPM for 2 minutes. If engine stalls, go to «TEST A - NO START»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-a-no-start) , step 13). If engine does not stall, go to next step.
12. With engine at operating temperature and tachometer installed, turn ignition off and wait 10 seconds. Activate «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) and perform Engine Running Self-Test while maintaining engine at 2000 RPM. If engine passes test or any codes are recorded, service codes as described for Engine Running Self-Test. If no codes are recorded, go to step 1 .
13. Output State Check Not Functioning. Turn ignition off and wait 10 seconds. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) and leave ignition on to enter Output State Check. If codes 23, 53, 63, or 68 are present in On Demand Test results, service codes as described for Key On-Engine Off Self-Test. If no codes 23, 53, or 63, leave ignition on and go to next step.
14. While in «Output State Test»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__output-state-test) under HOW TO USE CIRCUIT TEST, set DVOM on 20 volt scale. Measure voltage between Self-Test output circuit of Self-Test connector and battery positive terminal. Depress throttle to wide open position and release. Verify throttle is in closed position and note voltage reading. If greater than 10 volts, check throttle and linkage for sticking or binding and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If less than 10 volts, replace throttle position sensor (TPS) and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .

No Codes/Invalid Codes Circuit Diagram. Scheme 152

TEST E - COOLANT TEMPERATURE SENSOR

Note. To pass this test, coolant temperature must be 50-240°F (10-116°C) for Key On-Engine Off Self-Test and 180-240°F (82-116°C) for Engine Running Self-Test.

Scheme 153

1. Code 21. Start engine and bring to normal operating temperature. Check that upper radiator hose is hot and pressurized. Perform «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) before continuing. If code 21 appears, go to step 2. If no code 21, service other codes. If vehicle stalls, go to «TEST X - DIAGNOSIS BY SYMPTOM»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-x-diagnosis-by-symptom).
2. Turn ignition off and wait 10 seconds. Disconnect Engine Coolant Temperature (ECT) sensor and inspect connectors for damaged pins, corrosion and loose wires. Place DVOM on 20 volt scale. Turn ignition on. Measure voltage at ECT harness connector between coolant signal circuit and signal return circuit. If 4-6 volts, go to step 5. If less than 4 volts, go to step 3. If more than 6 volts, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
3. Turn ignition off and wait 10 seconds. With harness disconnected at ECT sensor, disconnect 60-pin connector at ECA. Inspect for damaged pins, corrosion and loose wires. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance of ECT harness connector between coolant signal circuit and box pin 7. Then measure resistance of connector between signal return circuit and box pin 46. If both readings are less than 5 ohms, go to step 4. If either is 5 ohms or greater, repair open circuit. Remove breakout box, reconnect ECA and ECT sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
4. Turn ignition off and connect breakout box. Disconnect ECA and ECT sensor. With DVOM on 200K ohm scale, measure resistance between box pin 7 and pins 40 and 60. If either reading is less than 10K ohms, service short circuit. Remove breakout box, reconnect ECA and ECT sensor and repeat Quick Test. If both readings are 10K ohms or more, go to step 5.
5. Reconnect ECA and ECT sensor. Remove breakout box. Warm engine to normal operating temperature, turn ignition off and wait 10 seconds. Disconnect harness at ECT sensor. With DVOM on 200K ohm scale, measure resistance of ECT sensor. In «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test), reading should be 1300-7700 ohms. In Engine Running Self-Test, reading should be 1550-4550 ohms. If both are within limits, replace ECA, reconnect sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If not within limits, replace ECT sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
6. Code 51 Turn ignition off and wait 10 seconds. Reconnect 60-pin connector at ECA and remove breakout box. Disconnect ECT sensor harness and inspect for damaged pins, corrosion and loose wires. Insert jumper wire in ECT sensor harness between coolant signal circuit and signal return circuit. Run «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). If code 61 appears, replace ECT sensor, remove jumper wire, reconnect harness and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If no code 61, go to step 7.
7. Turn ignition off and wait 10 seconds. Remove jumper. Disconnect 60-pin connector at ECA and inspect for damaged pins, corrosion and loose wires. Connect breakout box, leaving ECA disconnected. With DVOM on 200 ohm scale, measure resistance of ECT harness between coolant signal circuit and box pin 7 and signal return circuit and box pin 46. If either is 5 ohms or more, repair open in harness, remove breakout box, reconnect ECA and ECT sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If both are less than 5 ohms, replace ECA, remove breakout, reconnect ECA and ECT sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
8. Code 61 Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect for damaged pins, corrosion and loose wires. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). If code 51 appears, replace ECT and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If no code 51, go to step 9.
9. Turn ignition off and wait 10 seconds. With ECT disconnected, install breakout box and leave ECA disconnected. With DVOM on 200K ohm scale, measure resistance between box pin 7 to pins 40 and 60. If any less than 10K ohms, repair short in harness and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If both 10K ohms or more, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
10. Continuous Monitor Code 21. Turn ignition off and wait 10 seconds. Remove breakout box, reconnect ECA and ECT sensor and prepare vehicle for test drive (all test equipment removed). During test drive, try to simulate complaint and keep complaint active for at least one minute. After test drive, perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). If code 21 present, ensure thermostat is operating properly. If okay, replace ECT sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If no code 21, unable to duplicate fault at this time. Continuous Code 21 test complete.
11. Continuous Monitor Codes 51 and 61. Enter Continuous Monitor mode and observe volt/ohmmeter for fault indication while doing the following: Lightly tap on ECT sensor to simulate road shock. Wiggle sensor connector. If fault is indicated or voltage reading exceeds 5 volts, disconnect harness connectors at ECT and ECA. If connectors and terminals are okay, replace sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If no fault indicated, go to step 12. (Scheme 153): Engine Coolant Temperature Sensor Circuits
12. Observe volt/ohmmeter while performing the following: Beginning at ECT, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If no fault indicated, go to step 13.
13. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect connector and terminals for damage. If damaged, service as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If okay, fault cannot be duplicated at this time. Continuous Code 51 and 61 testing is complete.

TEST F - MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRESSURE (MAP/BP) SENS

1. Key On/Engine Off Code 22 Displayed. Turn key OFF. Disconnect MAP/BP sensor from wire harness. Connect MAP/BP tester between wire harness and MAP/BP sensor. Set DVOM to 20 volt scale and connect banana plugs from tester to DVOM. Go to step 2 .
2. Turn key ON. If ONLY Green light of tester comes on, VREF is correct. Go to step 4 of this test. If Red light (less than 4 volts) or no lights come on, VREF is too low. Go to step 3 . If Red light (greater than 6 volts) comes on, VREF is too high. Go to step 3 .
3. With MAP/BP tester connected, turn key ON. Disconnect MAP/BP sensor and repeat step 2 . If ONLY Green light comes on, VREF is correct. Replace MAP/BP sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If Red light (less than 4 volts) or no lights come on, VREF is too low. If Red light (greater than 6 volts) comes on, VREF is too high. Remove MAP/BP tester and go to «TEST B - VEHICLE BATTERY»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
4. Connect MAP/BP tester and turn ignition switch to "ON" position. Check output reading of sensor. Measure several known good MAP/BP sensors on other vehicles. Average of readings will be typical for date and location of testing. See chart in circuit diagram for correct output voltage readings. If readings are out of range, go to step 6 of this test. If readings are within range, go to step 5 .
5. Turn key OFF and wait 10 seconds. Disconnect MAP/BP sensor and 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between MAP/BP signal at connector and test pin 45. If reading is less that 5 ohms, replace ECA. Connect wiring and MAP/BP sensor. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is 5 ohms or more, repair open in circuit. Remove breakout box. Connect ECA and MAP/BP sensor. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
6. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect MAP/BP sensor and set DVOM to 200K ohm scale. Measure resistance between test pin 45 and test pins 26, 40, 46, and 60. If any reading is less than 10K ohms, repair short circuit. Remove breakout box and reconnect ECA. Reconnect MAP/BP sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If all readings are 10K ohms or more, replace MAP/BP sensor. Remove breakout box and connect all wiring. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
7. Engine Running Code 22 Displayed. Turn key OFF and wait 10 seconds. Disconnect vacuum line from MAP/BP sensor and connect vacuum pump to sensor pipe. Apply 18 in. Hg to sensor and check for vacuum leak. If sensor does not hold vacuum, replace it. Reconnect vacuum hose and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If MAP/BP sensor holds vacuum, release vacuum and go to step 8 .
8. Turn key OFF and wait 10 seconds. Plug MAP/BP vacuum supply hose and start engine. While holding 1400-1600 RPM, slowly apply 15 in. HG to MAP/BP sensor. Repeat Engine Running «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) while holding RPM level. Ignore all other codes during this step. If code 22 is still displayed, replace MAP/BP sensor. Connect vacuum line to MAP/BP sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 22 is not displayed, check vacuum supply hose and repair. If hose is good, repair other service codes if any are displayed. If no other codes are displayed, check engine and vacuum supply for cause of low vacuum.
9. Code 72 Displayed. Turn key OFF and wait 10 seconds. Connect vacuum gauge with "Tee" in line between intake manifold and MAP/BP sensor. Repeat Engine Running Quick Test and record service codes while observing vacuum reading. If vacuum decrease is 10 in. Hg or more and code 72 is NOT present, disconnect vacuum gauge and repair other codes. If vacuum decrease is 10 in. Hg or more and code 72 is displayed, replace MAP/BP sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If vacuum decrease is less than 10 in. Hg, go to step 10 .
10. Make sure that vacuum lines are routed correctly. Refer to VECI decal. Check hoses for kinks or blockage. If lines are good, EEC-IV system is good. Repair any mechanical causes of poor engine vacuum. If vacuum lines are bad, repair and repeat step 10).
11. Turn key OFF and disconnect MAP/BP sensor from harness. Connect MAP/BP tester between harness and sensor. Connect tester plugs to DVOM and set DVOM to 20 volt scale. Go to step 12 .
12. Repeat voltage output as done in step 4 . If reading is in range, go to «TEST L - CANISTER PURGE TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-l-canister-purge-test) . If reading is out of range, replace MAP/BP sensor.
13. Continuous Code 22 Displayed. While in Continuous Monitor mode, attach vacuum pump to MAP/BP sensor. Slowly apply 25 in. Hg to sensor and then slowly bleed vacuum off. Tap MAP/BP sensor lightly and wiggle connector. If fault is indicated, inspect for and repair any damaged wiring. If wiring is good, replace MAP/BP sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no fault is indicated, go to step 14 .
14. While still in monitor mode, wiggle and bend EEC-IV harness from MAP/BP sensor connector to firewall. Also wiggle and bend EEC-IV wiring from firewall to ECA. If fault is indicated, repair wiring and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no fault is indicated, go to step 15 .
15. Turn key OFF and wait 10 seconds. Disconnect ECA. Inspect for and repair any damaged wiring. If wiring is repaired, repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If wiring is good and fault cannot be duplicated, test is complete.

Manifold Absolute Pressure (MAP/BP) Sensor Circuit. Scheme 154

TEST G - THROTTLE POSITION SENSOR (TPS)

1. Code 23 (from Key On-Engine Off Self-Test). If code 68 is present, go to Test H. If no code 68, proceed with test. Before continuing with test, lightly press throttle lever toward actuator tip of idle speed motor while performing «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 23, go to step 3 . If no code 23, TPS is a little out of adjustment. DO NOT adjust TPS, EEC system is operating properly.
2. Code 23 (from Engine Running Self-Test). If code 58 is present, go to Test H. If no code 58, proceed with test. Before continuing with test, check for code 31 and/or 41 after performing Engine Running Self-Test. If code 31, go to «TEST DD - EGR VALVE POSITION (EVP) SENSOR»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 41, go to Test J. If no code 31 and/or 41, go to step 3 .
3. Inspect carburetor and throttle linkage for binding. Check that throttle linkage is at mechanical closed throttle. Check for binding speed control linkage and vacuum line or electrical harness interference. If throttle is not stuck, go to step 4 . If stuck, repair as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
4. Turn ignition off and wait 10 seconds. Disconnect TPS and inspect for damaged pins, corrosion, and loose wires. Repair as required. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) and record codes. If code 63, replace TPS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no code 63, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
5. Code 53. Turn ignition off and wait 10 seconds. Disconnect TPS and inspect. With DVOM on 20 volt scale, connect test leads to battery positive terminal and signal return circuit of TPS harness. If voltage is 10 volts or more, go to next step. If less than 10 volts, go to step 8 .
6. Ignition off, TPS disconnected and DVOM on 20 volt scale. Connect test leads to TPS harness between throttle position signal circuit and signal return circuit. Turn ignition on and note voltage. If less than 4 volts, go to step 7 . If 4 volts or more, go to step 9 .
7. Turn ignition off and wait 10 seconds. With TPS disconnected, perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 63 appears, replace TPS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no code 63, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
8. Turn ignition off and wait 10 seconds. With TPS disconnected, set DVOM on 200 ohm scale. Disconnect 60-pin connector at ECA and inspect for damage. Connect breakout box and leave ECA disconnected. Check continuity of TPS harness between signal return circuit and box pin 46. If less than 5 ohms, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If 5 ohms or more, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
9. Turn ignition off and wait 10 seconds. With same connections as in step 8 , set DVOM on 200K ohm scale. Measure resistance between box pin 47 to pins 26 and 57. If either is less than 10K ohms, repair short in harness and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If both 10K ohms or more, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
10. Code 63. ECA connected and breakout box disconnected. Turn ignition off and wait 10 seconds. Disconnect TPS and inspect. Place DVOM on 20 volt scale. Turn ignition on. Measure voltage of TPS harness from voltage reference circuit to throttle position circuit. If reading is 4-6 volts, go to step 11 . If less than 4 volts, go to step 13 . If 6 volts or more, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
11. Turn ignition off and wait 10 seconds. TPS disconnected. Disconnect 60-pin connector at ECA, inspect and repair as required. With DVOM on 200K ohm scale, connect 1 lead to throttle position signal circuit (47 to 26 and 57). If reading less than 10K ohms, repair short circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If 10K ohms or more, go to step 12 .
12. Turn ignition off and wait 10 seconds. TPS disconnected. Insert jumper wire into TPS harness between voltage reference circuit and throttle position signal circuit. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 53 (or 23), replace throttle position sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no code 53 (or 23), replace ECA.
13. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and connect ECA to breakout box (TPS disconnected). With DVOM on 200 ohm scale, measure continuity of TPS harness from throttle position signal circuit to box pin 47 and from voltage reference signal circuit to box pin 26. If either is 5 ohms or more, repair circuit, reconnect TPS, remove breakout box and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If less than 5 ohms, replace ECA, reconnect TPS, remove breakout box and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
14. Code 73. Code 73 indicates sensor did not exceed 25 percent of its rotation during Engine Response Check. Turn ignition off. Connect breakout box (TPS and ECA connected). With DVOM on 20 volt scale, measure voltage between box pins 47 and 46. Perform Engine Running Self-Test. If DVOM exceeds 3.5 volts during wide open throttle of Engine Response Check, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If less than 3.5 volts, verify TPS is properly mounted. If mounting is okay, replace TPS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
15. Continuous code 53. Using Continuous Monitor Mode, observe volt/ohmmeter for fault indication while doing the following: Move throttle slowly to wide open position. Slowly release throttle to closed position and lightly tap on TPS to simulate road shock. Wiggle TPS harness connector. If a fault is indicated, go to step 16 . If no fault indicated, go to step 19 .
16. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and reconnect ECA. With DVOM on 20 volt scale, connect leads between box pins 47 and 46. Turn ignition on. While observing DVOM, repeat step 15 . If fault is indicated below 4.25 volts, disconnect and inspect harness connectors. If okay, replace TPS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If fault does not occur, TPS overtravel may have caused Continuous Code 53. Sensor service not required. Proceed to step 17 to verify harness integrity.
17. Turn ignition off and wait 10 seconds. Remove breakout box, reconnect ECA and TPS. Watch volt/ohmmeter while doing the following: Beginning at TPS, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no fault indicated, go to step 18 .
18. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect both harness connector and ECA connector for damage or faults. If damaged, repair as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no damage or fault, unable to duplicate fault at this time. Continuous Code 53 test complete.
19. Continuous Monitor Code 63. Using Continuous Monitor Mode, observe volt/ohmmeter for fault indication while doing the following: Move throttle slowly to wide open position. Slowly release throttle to closed position and lightly tap on TPS to simulate road shock. Wiggle TPS harness connector. If a fault is indicated, disconnect and inspect harness connectors. If connectors and terminals okay, replace TPS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no fault indicated, go to step 20 .
20. Turn ignition off and wait 10 seconds. Watch volt/ohmmeter while doing the following: Beginning at TPS, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no fault indicated, go to step 21 .
21. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect for damage or fault. If terminals and pins are damaged, repair as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no damage, fault cannot be duplicated at this time. Continuous Code 63 test complete.

Throttle Position Sensor (TPS) Circuit. Scheme 155

TEST I - FBC FUEL CONTROL

1. Code 41. If engine ran for more than 2 minutes before performing Engine Running Self-Test, go to next step. If engine did not run for more than 2 minutes, prepare vehicle and perform Engine Running Self-Test.
2. Before continuing test, check oxygen sensor connection and ground for good connections. Check intake and exhaust manifolds for leaks. If all okay, go to step 3 . If not okay, repair problem and repeat Engine Running Self-Test.
3. Key off, wait 10 seconds. EGO Sensor disconnected. Disconnect processor 60 pin connector, inspect for damaged pins, corrosion, loose wires, etc. Service as necessary. Install breakout box, leave processor disconnected. DVOM on 200 Ohm scale. Measure resistance between test pin 29 and EGO circuit at the harness connector. Measure resistance between test Pin 49 and test pins 40 and 60. If all readings are less than 5 ohms, go to step 5 . Any reading is 5 ohms or greater, replace processor. Rerun «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
4. Turn ignition off. Reconnect ECA and oxygen sensor. Disconnect thermactor and cap air supply hose at air pump. Perform Engine Running Self-Test. Because thermactor hose is disconnected, code 11 does not indicate a pass. Treat code 11 as a code 44. If code 41 is present, leave thermactor hose disconnected and go to step 5 . If code 44 is present, perform Engine Running Self-Test. Ignore all other codes at this time.
5. Turn ignition off and wait 10 seconds. With thermactor hose disconnected, disconnect harness at FCS. Perform Engine Running Self-Test. If no code 41, go to step 7 . If code 41, go to step 6 . Ignore all other codes at this time.
6. Turn ignition off and wait 10 seconds. With FCS and thermactor hose disconnected, start and run engine at part throttle for 2 minutes. Turn ignition off and wait 10 seconds. Perform Engine Running Self-Test while holding choke 3/4 closed. DO NOT stall engine. If code 41, reconnect all disconnected components and go to step 10 . If no code 41, replace FCS and repeat Engine Running Self-Test.
7. Turn ignition off and wait 10 seconds. Reconnect thermactor hose and FCS. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 58 to pins 20, 40 and 46 in turn. If any less than 10K ohms, repair short circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If all readings 10K ohms or more, go to step 8 .
8. Turn ignition off. With breakout box installed, connect ECA to breakout box. Start and run vehicle at part throttle for 2 minutes. Turn ignition off and wait 10 seconds. Perform Engine Running Self-Test while holding choke 3/4 closed. DO NOT stall engine. If no code 41, go to step 9 . If code 41, replace FCS. Remove breakout box, reconnect FCS and ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
9. Turn ignition off and wait 10 seconds. With breakout box installed and ECA connected, disconnect harness at FCS. With DVOM on 2K ohm scale, measure resistance from feedback circuit of FCS harness connector to battery negative terminal. Then measure from vehicle power circuit of FCS harness connector to battery negative terminal. If either reading is less than 1,000 ohms, replace FCS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If both readings are 1,000 ohms or more, remove breakout box, replace ECA, and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
10. Turn ignition off and wait 10 seconds. With thermactor and FCS connected, disconnect harness at oxygen sensor. With DVOM on 200K ohm scale, measure resistance from oxygen sensor circuit of oxygen sensor harness connector to battery negative terminal. If less than 10K ohms, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If 10K ohms or more, go to step 11 .
11. Turn ignition off. With oxygen sensor disconnected, start and run engine for 2 minutes. Place DVOM on 20 volt scale. With engine running, hold choke 3/4 closed and measure voltage from oxygen sensor pigtail terminal to battery negative terminal. DO NOT stall engine. If less than .45 volt, replace oxygen sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If .45 volt or more, go to step 12 .
12. Ignition on and oxygen sensor disconnected. With DVOM on 20 volt scale, measure voltage from oxygen sensor circuit of oxygen sensor harness connector to battery negative terminal. If less than 2 volts, go to step 13 . If 2 volts or more, repair short circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
13. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. Disconnect oxygen sensor. With DVOM on 200 ohm scale, measure resistance from oxygen sensor circuit of oxygen sensor harness connector to box pin 29. Then measure from box pin 49 to pins 40 and 60. If all readings less than 5 ohms, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If any 5 ohms or more, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
14. Code 42. If choke functions properly without sticking or binding, go to the next step. If not, service choke assembly and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
15. Start and run engine at part throttle for 2 minutes. Turn ignition off and wait 10 seconds. Disconnect harness at oxygen sensor and jumper oxygen sensor circuit of oxygen sensor harness connector to ground. Perform Engine Running Self-Test. If code 41, go to step 16 . If no code 41, go to step 22 . Ignore all other codes.
16. Turn ignition off and wait 10 seconds. Reconnect oxygen sensor. Disconnect 7/32" vacuum line at intake manifold vacuum tree. Perform Engine Running Self-Test. If engine stalls, repeat test while manually maintaining engine speed at about 1500 RPM. If code 42 still present, replace oxygen sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 42 not present, go to step 17 . Ignore all other codes.
17. Turn ignition off and wait 10 seconds. Reconnect vacuum hose at intake manifold vacuum tree. Disconnect FCS and place DVOM on 200 ohm scale. Measure resistance between terminals on FCS. If resistance is 15-30 ohms, reconnect FCS and go to next step. If not 15-30 ohms, replace FCS and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . The resistance values given in this step apply to Holley Carburetors. For Carter YFA Carburetors the resistance should be 30-60 Ohms. For Motorcraft Carburetors, the resistance values should be 21-50 ohms.
18. Turn ignition off and wait 10 seconds. Enter Output State Check. Place DVOM on 20 volt scale. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until end of Continuous code display. DVOM will indicate 0 volts. Depress and release throttle. If DVOM indicated high voltage, remain in Output State Check and go to next step. If DVOM did not indicate high voltage, depress throttle to wide open position and release. If voltage still does not go high, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13).
19. While in Output State Check, turn ignition on and place DVOM on 20 volt scale. Connect DVOM between feedback circuit of FCS connector and battery negative terminal. While observing DVOM, depress and release throttle several times to cycle output on and off. If FCS cycles on and off, go to «TEST L - CANISTER PURGE TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-l-canister-purge-test) . If FCS does not cycle on and off, exit Output State Check and go to step 20 .
20. Turn ignition off and wait 10 seconds. Deactivate «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) and disconnect harness at FCS. With DVOM on 20 volt scale, turn ignition on. Measure voltage from voltage power circuit of FCS harness connector to battery negative terminal. If less than 10 volts, reconnect FCS, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If 10 volts or more, go to step 21 .
21. Turn ignition off and wait 10 seconds. Disconnect harness at FCS. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance from feedback circuit of FCS harness to box pin 58. If less than 5 ohms, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If 5 ohms or more, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
22. Turn ignition off and wait 10 seconds. Reconnect oxygen sensor. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. Turn ignition on. With DVOM on 20 volt scale, measure voltage from box pin 29 to battery negative terminal. If less than .4 volt, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 42 still present, go to «TEST K - (DC MOTOR) IDLE SPEED CONTROL (ISC DC MOTOR)»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-k-dc-motor-idle) . If .4 volt or more, repair short circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
23. Code 43. Start and run engine at 2000 RPM for 2 minutes. Perform Engine Running Self-Test. If code 43, go to step 24 . If no code 43, service other codes as necessary.
24. If there are any leaks at intake manifold or inlet pipe, repair as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If okay, go to step 25 .
25. Start engine and allow to idle. If idle quality weakens and remains poor during and after «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) , service carburetor. If not, replace oxygen sensor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .

EGR Valve Position (EVP) Sensor Circuit. Scheme 156

TEST K - (DC MOTOR) IDLE SPEED CONTROL (ISC DC MOTOR)

1. Code 12. If code 58 is also present, go to Test H. If code 58 is not present, go to next step.
2. If code 31 present, go to «TEST I - FBC FUEL CONTROL»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-i-fbc-fuel-control) I. If code 41 present, go to Test J. If no code 31 and/or 41, go to step 3 .
3. Check throttle plates and linkage for binding. Check speed control (if equipped) for binding. If okay, go to step 4 . If not okay, service as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
4. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. Disconnect harness at ISC motor. With DVOM on 200 ohm scale, check continuity from box pin 41 to negative ISC circuit and from box pin 21 to positive ISC circuit at ISC harness connector. If both are less than 5 ohms, go to step 5 . If either 5 ohms or more, repair faulty circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
5. Turn ignition on. Breakout box connected and ECA and ISC disconnected. With DVOM on 20 volt scale, measure voltage from box pin 41 to pins 40 and 60. Then measure from box pin 21 to pins 40 and 60. If all less than one volt, go to step 6 . If one volt or more, repair short circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 12 still present, replace ECA.
6. Turn ignition off and wait 10 seconds. Breakout box connected and ECA and ISC disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 41 to pins 40, 46 and 60 in turn. Then measure resistance from box pin 21 to pins 40, 46 and 60 in turn. If all read infinity, go to next step. If any 10K ohms or less, repair faulty circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 12 still present, replace ECA.
7. Turn ignition off and wait 10 seconds. Breakout box connected and ECA and ISC disconnected. With DVOM on 20 volt scale, connect positive lead to box pin 1 and negative lead to ground. If 10.5 volts or more, go to step 8 . If less than 10.5 volts, repair open in circuit No. 37 and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If code 12 still present, go to step 8 .
8. Turn ignition off and wait 10 seconds. Breakout box connected and ECA disconnected. Connect harness at ISC DC motor. Insert jumper wires between box pins 21 and 1 and between box pin 41 and ground. If ISC motor shaft extends 2" (51 mm), go to step 9 . If not, replace DC motor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
9. Turn ignition off and wait 10 seconds. Breakout box connected and ECA disconnected. Insert jumper wires between box pins 41 and 1 and between box pin 21 and ground. If ISC motor shaft retracts, go to step 10 . If not, replace DC motor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
10. Turn ignition off and wait 10 seconds. Breakout box connected and ECA disconnected. Insert jumper wires as outlined in step 8 . If motor shaft extends, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If not, replace DC motor and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
11. Code 13. Deactivate Self-Test and prepare vehicle for normal engine operation. Turn A/C on, if equipped. Start engine. Run for 3 minutes while alternating between idle for 30 seconds and part throttle for 5 seconds. If idle speed is erratic, check and repair vacuum leaks and service codes 22, 31, 41 and 58 before continuing. If idle speed is not erratic, go to next step.
12. Connect test equipment and perform Engine Running Self Test. If code 13, go to step 13 . If no code 13, repair other codes as required.
13. Check choke and throttle linkage for sticking or binding. Check to ensure throttle is not stuck on high step of cam. Repair as required and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If no binding or sticking, go to step 14 .
14. Perform Key On-Engine Off Self-Test. Record On Demand codes. If code 68, go to Test H, step 5). If no code 68, check anti diesel speed adjustment.

Idle Speed Control (DC Motor) Circuit. Scheme 157

TEST L - CANISTER PURGE TEST

1. With ignition key off, wait 10 seconds. Set DVOM on 200 ohm scale, disconnect CANP solenoid connector and measure solenoid resistance. If resistance is between 40-90 ohms, connect CANP solenoid and proceed to step 2 . If resistance is less than 40 ohms or greater than 90 ohms, replace CANP solenoid and repeat test.
2. With ignition key off, wait 10 seconds. Set DVOM on 20 volt scale, connect negative lead to STO and positive lead to battery positive. Jumper STI to signal return. Enter Output State Check (Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until completion of the continuous test codes). DVOM will indicate 0 volts, depress and release throttle. If a high voltage reading was obtained, remain in output state check and go to step 3 . If a high voltage reading was not obtained, depress throttle to WOT and release. If STO voltage does not go to a high reading, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13).
3. Leave equipment hooked up and DVOM on 20 volt scale. Connect positive test lead to VPWR on CANP solenoid and negative lead to CANP output circuit. Depress and release the throttle several times while watching DVOM, this will cycle output on and off. If CANP output cycles on and off, go to step 4 . If CANP does not cycle on and off, remove jumper and go to step 5 .
4. With ignition key off, wait 10 seconds. Remove jumper wire from STI to signal return. Disconnect vacuum hose at canister purge solenoid at PCV side and apply 16 in. Hg vacuum to CANP solenoid. If CANP solenoid holds vacuum for 20 seconds, EEC-IV system is OK, check fuel system. If the CANP solenoid does not hold vacuum for 20 seconds, replace CANP solenoid and repeat test. If code 42 is still present, check fuel system.
5. With key on, engine off, connect DVOM (scale set on 20 volts) positive test lead to VPWR and negative lead to ground. If CANP solenoid voltage is less than 10.5 volts, service harness open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If CANP solenoid voltage is 10.5 volts or greater go to step 6 .
6. With key off, wait 10 seconds. Disconnect ECA, inspect both 60-pin connectors, and service as necessary. Connect breakout box to harness and leave ECA disconnected. Measure continuity from test pin 35 to CANP at harness connector with DVOM on 200 ohm scale. If reading is 5 ohms or greater, service open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is less than 5 ohms go to step 7 .
7. With key off, wait 10 seconds. Breakout box installed (ECA disconnected). With DVOM on 200K ohm scale and CANP solenoid disconnected, measure resistance from test pin 35 to test pins 37 and 57. If resistance is 10K ohms or greater go to next step. If resistance is less than 10K ohms, service short to power and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
8. With key off, wait 10 seconds. Leave breakout box installed and ECA disconnected. With DVOM on 200K ohm scale, measure resistance of test pin 35 to test pins 40, 46, and 60. If resistance is less than 10K ohms, service short to ground and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If resistance is 10K ohms or greater, remove breakout box, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .

Canister Purge Solenoid Circuit. Scheme 158

TEST M - AIR CHARGE TEMPERATURE (ACT) SENSOR

Note. Ambient air temperature must be greater than 50°F (10°C) for this test.

1. Code 24. For vehicles with ACT sensor mounted in intake manifold, go to step 2 . On all other models, if sensor is properly mounted in air cleaner, go to step 2 . If sensor is not properly mounted, install properly and repeat Self Test.
2. Turn ignition off and wait 10 seconds. Disconnect harness at ACT and check for damaged pins or corrosion. Repair as required. Turn ignition on (engine off). With DVOM on 20 volt scale, measure voltage from ACT signal circuit and signal return circuit of sensor harness. If reading is 4-6 volts, go to step 5 . If reading is less than 4 volts, go to step 3 . If reading is greater than 6 volts, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
3. Turn ignition off and wait 10 seconds. Harness disconnected at ACT sensor. Disconnect 60-pin connector at ECA. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance from box pin 26 to ACT signal circuit of sensor connector. Then measure resistance from box pin 46 to signal return circuit of sensor connector. If both readings less than 5 ohms, go to step 4 . If either reading 5 ohms or more, repair open circuit and repeat Self Test.
4. Turn ignition off. Breakout box connected and ECA and ACT disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 25 to pins 40, 46 and 60 in turn. If any reading less than 10K ohms, repair short circuits and repeat Self Test. If all readings are 10K ohms or more, go to step 5 .
5. Remove breakout box and reconnect all connectors. Warm engine to normal operating temperature. Turn ignition off and wait 10 seconds. Disconnect harness at ACT sensor. With DVOM on 200K ohm scale, measure resistance of sensor. If 1100-58K ohms (at about 50°F/10°C), go to next step. If less than 1100 ohms or more than 58K ohms, check heat stove duct valve operation. If duct valve operation is okay, replace sensor and repeat Self Test.
6. Turn ignition off. With harness disconnected at ACT sensor, start and run engine for 2 minutes. With DVOM on 200K ohm scale, measure resistance of sensor while engine is running. If reading is 2400-29K ohms, replace ECA and repeat Self Test. If reading is less than 2400 ohms or greater than 29K ohms, check heat stove duct valve operation. If duct valve operation is okay, replace sensor and repeat Self Test.
7. Code 54. Turn ignition off and wait 10 seconds. Disconnect harness at ACT sensor and inspect for damage. Repair as required. Insert jumper wire between ACT signal circuit and signal return circuit of harness. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 64 present, replace sensor and repeat Self Test. If no code 64, remove jumper wire and go to step 8 .
8. Turn ignition off and wait 10 seconds. ACT connector disconnected. Disconnect 60-pin connector at ECA and inspect for damage. Repair as required. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance between box pin 25 and ACT signal circuit of ACT harness. Then measure between box pin 46 and signal return circuit of ACT harness. If both readings are less than 5 ohms, replace ECA and repeat Self Test. If either reading is 5 ohms or more, repair open circuit and repeat Self Test.
9. Code 64. Turn ignition off and wait 10 seconds. Disconnect harness at ACT sensor and inspect. Repair as required. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 54, replace ACT sensor and repeat Self Test. If no code 54, go to step 10 .
10. Turn ignition off and wait 10 seconds. Harness disconnected at ACT sensor. Disconnect 60-pin connector at ECA and inspect. Repair as required. Connect breakout box and leave ECA disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 25 to pins 40, 46 and 60 in turn. If any reading less than 10K ohms, repair short circuit and repeat Self Test. If all readings 10K ohms or more, replace ECA and repeat Self Test.
11. Continuous codes 54 and 64. Breakout box disconnected and ECA and ACT connected. Enter Continuous Monitor mode and observe volt/ohmmeter for fault indication while doing the following: Lightly tap on ACT sensor to simulate road shock. Wiggle sensor connector. If fault is indicated, disconnect harness connectors at ACT and ECA. If connectors and terminals are okay, replace sensor and repeat Self Test. If no fault indicated, go to step 12 .
12. Observe volt/ohmmeter while performing the following: Beginning at ACT, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat Self Test. If no fault indicated, go to step 13 .
13. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect connector and terminals for damage. If damaged, service as required and repeat Self Test. If okay, fault cannot be duplicated at this time. Continuous Code 54 and 64 testing is complete.

Air Charge Temperature (ACT) Sensor Circuit. Scheme 159

TEST O - AIR MANAGEMENT SYSTEM

1. Codes 81 and 82. Check air and vacuum lines to TAB/TAD solenoids and by-pass diverter valve for blockage, leaks, restrictions and proper routing. Repair as required and repeat Self Test. If lines okay, go to step 4 for code 44; next step for code 45 and step 3 for code 46.
2. Disconnect and plug vacuum line at diverter valve. Turn ignition off and wait 10 seconds. Perform Engine Running Self-Test and record codes. If code 45 present, EEC system okay, repair diverter valve or check valve. If no code 45, go to step 3 .
3. Disconnect and plug vacuum line at by-pass valve. Turn ignition off and wait 10 seconds. Perform Engine Running Self-Test and record codes. If code 46 present, EEC system okay, repair by-pass valve. If no code 46, go to step 4 .
4. Turn ignition off and wait 10 seconds. Enter Output State Check and perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until end of Continuous code display. DVOM will indicate zero volts. Depress and release throttle and observe DVOM. If DVOM indicates high reading, remain in Output State Check and go to step 5 . If DVOM does not indicate high reading, depress throttle to wide open position and release. If DVOM still does not indicate high reading, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13). Leave equipment connected.
5. Disconnect vacuum line at TAB solenoid supply port and install vacuum pump. Disconnect vacuum line at TAB solenoid output port and install vacuum gauge. While maintaining vacuum on TAB solenoid, depress and release throttle to cycle output on and off and observe vacuum gauge. Repeat procedure for TAD solenoid. If both vacuum outputs cycled on and off, go to next step. If either vacuum output does not cycle on and off, replace TAB/TAD solenoid assembly and repeat Self Test.
6. Disconnect TAB solenoid-to-thermactor valve vacuum hose. Connect vacuum pump and gauge and test hose for blockage and leaks. Repeat procedure for TAD solenoid-to-thermactor valve vacuum hose. Repair as required and repeat Self Test. If vacuum lines okay, go to next step.
7. Disconnect vacuum lines at TAB/TAD solenoids and start engine. If vacuum is present, EEC system okay, service air pump or thermactor valve. If vacuum is not present, repair source of vacuum leak or blockage and repeat Self Test.

Air Management System Circuit. Scheme 160

TEST P - EGR VENT (EGRV) & EGR CONTROL (EGRC) VALVE OUTPUT CIRCUIT CHECK

1. Codes 83 and 84. Turn ignition off and wait 10 seconds. Disconnect harness at EGR vent solenoid and EGR control solenoid. With DVOM on 200 ohm scale, measure resistance of solenoids. If both readings are 30-70 ohms, reconnect solenoids and go to next step. If either reading is less than 30 ohms or greater than 70 ohms, replace solenoid assembly and repeat Self Test.
2. Turn ignition on (engine off). With DVOM on 20 volt scale, connect positive lead to vehicle power circuit of EGR vent solenoid harness and negative lead to good ground. Repeat test on EGR control solenoid harness. If both readings greater than 10.5 volts, go to next step. If either reading less than 10.5 volts, repair open circuit and repeat Self Test.
3. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Repair as required. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure continuity from box pin 33 to EGR vent circuit at EGR vent solenoid harness. Then measure from box pin 52 to EGR control circuit at EGR control solenoid harness. If both readings less than 5 ohms, go to step 4 . If either reading 5 ohms or more, repair open circuit and repeat Self Test.
4. Turn ignition off and wait 10 seconds. Disconnect harness at EGR vent solenoid and EGR control solenoid. Breakout box installed and ECA disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 33 to pins 37 and 57. Then measure from box pin 52 to same pins. If any reading less than 10K ohms, repair short to power and repeat Self Test. If any reading 10k ohms or more, go to step 5 .
5. Turn ignition off and wait 10 seconds. Breakout box installed and ECA and EGR vent and EGR control solenoids disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 33 to pins 40, 46 and 60 in turn. Then measure from box pin 52 to same pins. If any reading less than 10K ohms, repair short to ground and repeat Self Test. If any reading 10K ohms or more, replace ECA and repeat Self Test.

EGR Vent Solenoid & EGR Control Solenoid Circuits. Scheme 161

TEST R - TEMPERATURE COMPENSATED PUMP (TCP) OUTPUT CIRCUIT CHECK

1. Turn ignition off and wait 10 seconds. Disconnect temperature compensated accelerator pump solenoid harness connector. With DVOM on 200 ohm scale, measure resistance of solenoid. If resistance is between 50-100 ohms, reconnect solenoid and go to next step. If less than 50 ohms or greater than 100 ohms, replace solenoid and repeat Self Test.
2. Turn ignition on (engine off). With DVOM on 20 volt scale, connect positive lead to vehicle power circuit of solenoid harness connector and negative lead to ground. If voltage is less than 10.5 volts, repair open circuit in harness and repeat Self Test. If greater than 10.5 volts, go to step 3 .
3. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect for damage. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure continuity from box pin 54 to TCP circuit at solenoid harness connector. If 5 ohms or greater, repair open circuit in harness and repeat Self Test. If less than 5 ohms, go to next step.
4. Turn ignition off and wait 10 seconds. Breakout box installed (ECA and TCP solenoid disconnected). With DVOM on 200K ohm scale, measure resistance from box pin 54 to box pins 37 and 57. If resistance is 10K ohms or greater, go to next step. If less than 10K ohms, repair short circuit and repeat Self Test.
5. Turn ignition off and wait 10 seconds. Breakout box installed (ECA and TCP solenoid disconnected). With DVOM on 200K ohm scale, measure resistance from box pin 54 to box pins 40, 46, and 60. If readings are less than 10K ohms, repair short to ground and repeat Self Test. If readings are 10K ohms or greater, replace ECA and repeat Self Test.

Temperature Compensated Accelerator Pump Output Circuit. Scheme 162

TEST S - VARIABLE VOLTAGE CHOKE (VVC) OUTPUT CIRCUIT CHECK

1. With DVOM on 20V scale, perform Engine Running Self-Test. Measure choke voltage. If voltage is 10.5 volts or greater, check choke plates for binding and sticking (EEC-IV system operating properly). If choke voltage is less than 10.5 volts, go to step 2 .
2. Turn ignition off and wait 10 seconds. With DVOM on 20V scale, connect negative test lead to STO and positive lead to battery positive. Jumper STI to signal return. Enter Output State Check (Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until the completion of continuous test codes). DVOM will indicate zero volts. Depress and release throttle. If DVOM reading changed to high voltage, remain in Output State Check and go to next step. If not, depress throttle to wide open position and release. If voltage still does not go high, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13).
3. Ignition on (engine off). With DVOM on 20V scale, connect positive lead to V PWR on VCV relay and negative lead to VVC output circuit VVC. Depress and release throttle several times to cycle output on and off. If output cycles on and off, go to next step. If output does not cycle on and off, remain in Output State Check and go to step 5 .
4. Turn ignition off and wait 10 seconds. DVOM should be on 200 ohm scale. Measure resistance of ground circuit from relay harness connector. Measure resistance of choke circuit from the relay harness connector to the choke. If either resistance is 5 or more ohms, service harness circuit and repeat Self Test. If both resistances are 5 ohms or greater, replace choke relay and repeat Self Test.
5. Ignition on (engine off). With DVOM on 20 volt scale, connect DVOM positive lead to vehicle power circuit at relay harness connector and negative lead to ground circuit at relay harness connector. If voltage is less than 10.5 volts, service open in choke power circuit and repeat Self Test. If voltage is 10.5 volts or greater, go to step 6 .
6. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure continuity from box pin 55 to VVC circuit at harness relay connector. If resistance is 5 ohms or greater, repair harness circuit and repeat Self Test. If resistance is less than 5 ohms, go to step 7 .
7. Turn ignition off and wait 10 seconds. With DVOM on 200K ohm scale, leave breakout box installed and ECA disconnected. With VVC relay disconnected, measure resistance from box pin 55 to box pins 1, 37 and 57. If resistance is less than 10K ohms, repair short to power and repeat Self Test. If greater than 10K ohms, go to step 8 .
8. Turn ignition off and wait 10 seconds. Turn DVOM to 200K ohm scale. VVC relay should be connected. Leave breakout box installed and ECA disconnected. Measure resistance from box test pin 55 to pins 40, 46 and 60. If any resistance values are less than 10K ohms, replace ECA and repeat Self Test. If readings are greater than 10K ohms, go to step 9 .
9. Turn ignition off and wait 10 seconds. Leave breakout box installed and ECA disconnected. With DVOM on 200K scale, disconnect VVC relay. Measure resistance from box pin 55 to pins 40, 46 and 60. If all resistances are greater than 10K ohms, replace choke relay and repeat Self Test. If any resistances are less than 10K ohms, repair harness short and repeat Self Test.

Variable Voltage Choke Circuit Diagram. Scheme 163

TEST T - SPARK TIMING CHECK

1. If spark advance was not 27-33° in Engine Running Self Test, place system in Self-Test. After last Self-Test service code is displayed, system returns to normal after 2 minutes and spark timing will no longer be locked at 30°.
2. Connect timing light to engine. Locate spark output circuit to TFI module and open the connection. Start engine and check base timing. Base timing is 7-13° BTDC. If timing is correct, go to step 3 . If timing is not correct, reconnect spark output circuit and set base timing. After timing is adjusted, repeat Self Test.
3. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Connect breakout box. Turn ignition on. With DVOM on 20 volt scale, measure voltage from box pin 37 to pin 40 and from box pin 57 to pin 60. If either reading is less than 10.5 volts, perform «TEST B - VEHICLE BATTERY»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If both readings are 10.5 volts or more, go to step 4 .
4. Turn ignition off and wait 10 seconds. Disconnect harness connector at TFI module. With DVOM on 200 ohm scale, measure spark output circuit from spark output pin (pin 2) on TFI harness connector to box pin 36. If 5 ohms or less, continue to next step. If more than 5 ohms, repair open circuit. Check timing as described in step 1 .
5. Install breakout box, leave TFI harness disconnected. With ignition off, place DVOM on 200 ohm scale. Measure resistance from box pin 16 to TFI harness connector ignition ground pin (pin 6). If less than 5 ohms, go to «TEST A - NO START»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-a-no-start) , step 7). If 5 ohms or more, repair harness as required and repeat Self Test.

Spark Advance Test Circuit. Scheme 164

TEST V - THERMACTOR OUTPUT CIRCUIT CHECK

1. Turn ignition off and wait 10 seconds. Disconnect harness at TAB and TAD solenoids. With DVOM on 200 ohm scale, measure resistance of TAB and TAD solenoids. If both readings 50-100 ohms, reconnect solenoids and go to next step. If either reading less than 50 ohms or more than 100 ohms, replace TAB/TAD solenoid assembly and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
2. Turn ignition on (engine off). With DVOM on 20 volt scale, connect positive lead to vehicle power circuit of TAB solenoid and negative lead to good ground. Repeat test on TAD solenoid. If both readings 10.5 volts or more, go to step 3 . If either reading less than 10.5 volts, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
3. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Repair as required. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure continuity from box pin 51 to TAB circuit at TAB harness. Then measure from box pin 11 to TAD circuit at TAD harness. If both readings less than 5 ohms, go to next step. If either reading 5 ohms or more, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
4. Turn ignition off and wait 10 seconds. Breakout box installed and ECA and TAB/TAD solenoid disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 51 to pins 37 and 57. Then from box pin 11 to same pins. If all readings 10K ohms or more, go to step 5 . If any reading less than 10K ohms, repair short to power and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
5. Turn ignition off and wait 10 seconds. Breakout box installed and ECA and TAB/TAD solenoid disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 51 to pins 40, 46 and 60 in turn. Then from box pin 11 to same pins. If all readings less than 10K ohms, repair short to ground and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If any reading 10K ohms or more, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .

Thermactor Circuit. Scheme 165

TEST W - DYNAMIC RESPONSE TEST

Code 77. This code appeared because the system failed to recognize a brief wide open throttle. Repeat Engine Running Self-Test. After Dynamic Response Code is received, perform a wide open throttle. If code 77 is still present, replace ECA and repeat Self-Test. If no code 77, Dynamic Response Test is passed. Repair any service codes received as required.

TEST X - DIAGNOSIS BY SYMPTOM

1. If engine stalls in Self-Test, runs rough or misses, check the following: Poor power/ground connections, ignition system problem, engine internal problem (valves, cam timing, compression, etc.), EGR valve or fuel system.
2. If shift indicator light is always on or always off, go to Test Y. If A/C does not cut off during wide open throttle operation, or is not functioning, go to «TEST K - (DC MOTOR) IDLE SPEED CONTROL (ISC DC MOTOR)»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-k-dc-motor-idle) . If there is high or low idle speed on start up, or engine diesels, go «TEST Z - KEY POWER TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-z-key-power-test) .
3. If gasoline fumes accumulate under hood, check fuel system and canister purge system. If there is a lack of fast idle with A/C on, go to «TEST K - (DC MOTOR) IDLE SPEED CONTROL (ISC DC MOTOR)»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-k-dc-motor-idle) .

TEST Z - KEY POWER TEST

1. Turn ignition off and wait 10 seconds. Install breakout box with ECA connected. Set DVOM on 20 volt scale, connect leads to pins 5 and 60. Perform Engine Running Self-Test. If DVOM reading exceeds 17.5 volts during Self Test, repair charging system. If reading remains below 17.5 volts and code 65 is present, replace ECA and repeat Self Test. If DVOM remains below 17.5 volts and code 65 is not present, go to step 2 .
2. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) . If code 65 is not present, charging system is okay, test complete. If code 65 is present, check charging system.

Key Power Circuit. Scheme 166

TEST AA - VARIABLE VOLTAGE CHOKE (VVC) TEST

1. Perform Engine Running Self-Test. With DVOM on 20 volt scale, measure choke voltage. If voltage is 10.5 volts or greater, check choke plates for binding and sticking. If choke plates are not binding or sticking, EEC-IV system is operating properly, repair choke system. If voltage is less than 10.5 volts, go to step 2 .
2. Turn ignition on (engine off). Set DVOM on 20 volt scale, connect positive lead to vehicle battery circuit at relay harness connector and negative lead to ground at relay harness connector. If less than 10.5 volts, repair open circuit and repeat Self Test. If voltage is 10.5 volts or greater, go to step 3 .
3. Turn ignition off and disconnect 60-pin connector at ECA. Install breakout box and reconnect ECA. Turn ignition on (engine off). With DVOM on 20 volt scale, measure voltage from box pins 40 and 60 to negative battery terminal. If both are less than 1 volt, ground circuit is okay, go to next step. If voltage is 1 volt on one or both circuits, repair ground circuit and repeat Self Test.
4. Turn ignition off and wait 10 seconds. Enter Output State Check and perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until end of Continuous code display. DVOM will indicate zero volts. Depress and release throttle and observe DVOM. If DVOM registered high voltage, remain in Output State Check and go to step 5 . If DVOM did not register high voltage, depress throttle to wide open position and release. If voltage still does not register high reading, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13).
5. Remain in Output State Check. Turn ignition on, engine off. Set DVOM on 20 volt scale, connect positive lead to vehicle battery circuit on choke relay and negative lead to variable voltage choke output circuit at choke. While observing DVOM, depress and release throttle several times to cycle output on and off. If output cycles on and off, EEC-IV system is operating properly, repair choke system. If output does not cycle on and off, replace choke relay and repeat Self-Test.

Variable Voltage Choke Circuit. Scheme 167

TEST BB - TEMPERATURE COMPENSATED ACCELERATOR PUMP (TCP) TEST

1. Turn ignition off and wait 10 seconds. Disconnect temperature compensated accelerator pump solenoid harness connector. Set DVOM on 200 ohm scale, measure resistance of solenoid. If resistance is between 50-100 ohms, reconnect solenoid and go to next step. If less than 50 ohms or greater than 100 ohms, replace solenoid and repeat Self-Test.
2. Turn ignition off and wait 10 seconds. Enter Output State Check and perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until end of Continuous code display. DVOM will indicate zero volts. Depress and release throttle and observe DVOM. If DVOM registered high voltage, remain in Output State Check and go to step 3 . If DVOM did not register high voltage, depress throttle to wide open position and release. If voltage still does not register high reading, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13).
3. Remain in Output State Check. Turn ignition on, engine off. With DVOM on 20 volt scale, connect positive lead to vehicle battery circuit on solenoid and negative lead to temperature compensated pump output circuit at solenoid. While observing DVOM, depress and release throttle several times to cycle output on and off. If output cycles on and off, go to step 4 . If output does not cycle on and off, go to step 6 .
4. Remain in Output State Check. Install vacuum pump to solenoid vacuum supply port and vacuum gauge to solenoid output port. Apply and maintain a minimum of 6 in. Hg vacuum. Depress and release throttle several times to cycle vacuum output on and off and observe vacuum gauge. If vacuum output cycles on and off, go to step 5 . If vacuum does not cycle on and off, replace solenoid and repeat Self Test.
5. Remove all test equipment and vacuum source. Disconnect vacuum lines at temperature compensated accelerator pump solenoid. Start engine and check for vacuum. If vacuum is present, EEC-IV system is operating properly, check fuel system. If no vacuum is present, repair vacuum leak or blockage and repeat Self-Test.
6. Turn ignition on (engine off). With DVOM on 20 volt scale, connect positive lead to vehicle power circuit at solenoid connector and negative lead to ground. If voltage is 10.5 volts or less, repair open circuit and repeat Self-Test. If voltage is 10.5 volts or greater, go to step 7 .
7. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect connectors for damage. Repair as required. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure continuity from box pin 54 to temperature compensated pump circuit at harness connector. If resistance is 5 ohms or greater, repair open circuit and repeat Self Test. If less than 5 ohms, go to step 8 .
8. Turn ignition off and wait 10 seconds. Disconnect harness at pump solenoid. Install breakout box (ECA disconnected). With DVOM on 200K ohm scale, measure resistance from box pin 54 to box pins 37 and 57. If resistance is 10K ohms or greater, go to step 9 . If resistance is less than 10K ohms, repair short and repeat Self-Test.
9. Turn ignition off and wait 10 seconds. Breakout box installed (ECA and solenoid disconnected). With DVOM On 200K ohm scale, measure resistance from box pin 54 to pins 40, 46, and 60. If readings are less than 10K ohms, repair short to ground and repeat Self Test. If readings are 10K ohms or greater, replace ECA and repeat Self-Test.

Temperature Compensated Accelerator Pump Output Circuit. Scheme 168

TEST CC - CONVERTER CLUTCH OVERRIDE (CCO)

1. Code 89. Turn key on. Set DVOM on 20 volt scale. Measure voltage at the CCO solenoid connector between VPWR and ground. If voltage reading is less than 10.5 volts, repair open circuit in harness. Repeat Self-Test. If voltage reading is more than 10.5 volts, go to step 2 .
2. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector and inspect for damaged pins, corrosion, loose wires, etc. Repair as necessary and go to step 3 .
3. Connect breakout box to harness. Leave processor disconnected. Set DVOM on 200 ohm scale. Measure resistance between test pin 53/22 and CCO circuit at the solenoid harness connector. If resistance readings are 5 ohms or greater, repair harness circuit. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If resistance reading is less than 5 ohms, go to step 4 .
4. Turn key off and wait 10 seconds. Leave breakout box installed and processor disconnected. Disconnect CCO solenoid. Set DVOM on 200K ohm scale. Measure resistance between test pin 55 and test pins 40, 46 and 60. If resistance readings are less than 10K ohms, repair short to ground. Repeat Self Test. If resistance readings are 10K ohms or greater, go to step 5 .
5. Turn key off and wait 10 seconds. Set DVOM on 200K ohm scale. Leave breakout box installed and processor disconnected. Disconnect CCO solenoid. Measure resistance between test pin 55 and pins 37 and 57. If resistance reading is 10K ohms or greater, replace processor. Repeat Self Test. If resistance reading is less than 10K ohms, repair short to power supply. Repeat Self Test. If code is still present, replace processor.

Converter Clutch Override (CCO). Scheme 169

Scheme 170

1. Code 31. Turn ignition off and wait 10 seconds. Disconnect and plug EGR vacuum line at EGR valve. Perform Engine Running Self-Test. If code 31, go to step 2. If no code 31, but codes 32 and/or 34 present, go to step 9.
2. Turn ignition off and wait 10 seconds. EGR vacuum line disconnected and plugged at EGR valve. Disconnect harness connector at EGR valve position (EVP) sensor and inspect terminals for damage. Repair as required. With DVOM on 200,000 ohm scale, measure resistance from EVP signal circuit to voltage reference circuit at EVP sensor. Then measure resistance from signal return circuit to voltage reference circuit at sensor. If both readings are 100-5500 ohms, go to next step. If either reading is less than 100 ohms or more than 5500 ohms, replace sensor and repeat Self Test.
3. Ignition off, EGR vacuum line disconnected and plugged and harness disconnected at EVP sensor. Connect vacuum pump to EGR valve. With DVOM on 200K ohm scale, measure resistance from EVP signal circuit to voltage reference circuit at EVP sensor while gradually increasing vacuum to 10 in. Hg. If reading gradually decreased from no more than 5500 ohms to no less than 100 ohms as vacuum is increased, go to next step. If reading is less than 100 ohms or more than 5500 ohms as vacuum is increased, replace sensor and repeat Self-Test. If reading does not decrease or sensor does not hold vacuum, go to step 12.
4. Turn ignition on (engine off). EGR vacuum line disconnected and plugged and harness disconnected at EVP sensor. With DVOM on 20 volt scale, measure voltage from voltage reference circuit to signal return circuit at sensor harness. If reading is 4-6 volts, go to next step. If reading is less than 4 volts, go to step 7. If reading is greater than 6 volts, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
5. Ignition on (engine off). Reconnect EGR vacuum line at EGR valve and leave harness disconnected. With DVOM on 20-volt scale, measure voltage from voltage reference circuit to EVP signal circuit at sensor harness. If reading is 4-6 volts, go to step 6. If reading is less than 4 volts, go to step 7.
6. Turn ignition off and wait 10 seconds. Harness disconnected at EVP sensor. Disconnect 60-pin connector at ECA and inspect for damaged terminals. Repair as required. With DVOM on 200K ohm scale, measure resistance from EVP signal circuit to signal return circuit at sensor harness and from EVP signal circuit to battery negative terminal. If either reading is less than 10K ohms, repair short circuit and repeat Self Test. If both readings are 10K ohms or more, replace ECA and repeat Self Test.
7. Turn ignition off and wait 10 seconds. Harness disconnected at EVP and ECA. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale, measure continuity from box pin 46 to signal return circuit of EVP harness; from box pin 26 to voltage reference circuit of EVP harness and from box pin 27 to EVP signal circuit of EVP harness. If all readings less than 5 ohms, go to step 8. If any reading 5 ohms or more, repair open circuit and repeat Self Test.
8. Ignition off, EVP harness disconnected, breakout box installed and ECA disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 27 to pins 37 and 57. If either reading is less than 10K ohms, repair short circuit and repeat Self Test. If both readings are 10K ohms or more, replace ECA and repeat Self Test.
9. Codes 32, 33 and 34. Turn ignition off and wait 10 seconds. Enter Output State Check and perform Key On-Engine Off Self Test until end of Continuous code display. DVOM will indicate zero volts. Depress and release throttle and observe DVOM. If DVOM registered high voltage, remain in Output State Check and go to next step. If DVOM did not register high voltage, depress throttle to wide open position and release. If voltage still does not register high reading, go to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes), step 13).
10. Turn ignition on (engine off). Remain in Output State Check. Disconnect and plug vacuum line at bottom port of EGR control solenoid and connect vacuum pump. Using a "Tee", connect vacuum gauge in top line at EGR valve. Disconnect but DO NOT plug vacuum vent line at EGR vent solenoid. Apply vacuum and observe vacuum gauge while depressing and releasing throttle (cycling outputs on and off). If vacuum output cycles on and off in less than 2 seconds, reconnect vacuum lines and go to next step. If vacuum output does not cycle on and off in less than 2 seconds, replace solenoid assembly and repeat Self Test.
11. Turn ignition off and wait 10 seconds. Remove all test equipment and reconnect all vacuum lines. Check EEC system vacuum lines for proper routing, leaks and obstructions. Repair as required. If vacuum lines are okay, service EGR system.
12. Ignition off and harness disconnected at EVP sensor. Remove EVP sensor from EGR valve. With DVOM on 200K ohm scale, measure resistance from signal return circuit to voltage reference circuit at EVP sensor. Observe DVOM while slowly pushing EVP sensor shaft inward. If reading smoothly decreases from no more than 5500 ohms to no less than 100 ohms, replace EGR valve assembly and repeat Self Test. If reading does not decrease smoothly or changes suddenly, replace EVP sensor and repeat Self Test.
13. Code 35 (RPM too low for EGR test). Before continuing, check for codes 12 and 13. If code 12 or 13 present, go to «TEST K - (DC MOTOR) IDLE SPEED CONTROL (ISC DC MOTOR)»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-k-dc-motor-idle). If no code 12 or 13, go to step 14.
14. Turn ignition off and wait 10 seconds. Install tachometer and perform Engine Running Self-Test while maintaining engine speed at 1500 RPM. Record Engine Running service codes. If code 35 present, replace ECA and repeat Self Test. If no code 35, repeat Self Test and repair codes as required.
15. Turn ignition off and wait 10 seconds. Disconnect EVP sensor and inspect harness and connector terminals. Repair as required. Turn ignition on (engine off). With DVOM on 20 volt scale, measure voltage from voltage reference circuit at sensor harness to battery ground. If reading is 4-6 volts, go to next step. If reading is less than 4 volts, go to step 7. If reading is 6 volts or more, go to «TEST C - REFERENCE VOLTAGE»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
16. Ignition on and EVP sensor disconnected. With DVOM on 20 volt scale, measure voltage from voltage reference circuit to signal return circuit at sensor harness. If reading is 4-6 volts, go to next step. If reading is less than 4 volts, repair open circuit and repeat Key On-Engine Off Self-Test.
17. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Repair as required. Connect breakout box and reconnect ECA. Connect EVP sensor. Turn ignition on (engine off). With DVOM on 20 volt scale, measure voltage from box pin 27 to pin 46. If less than.5 volt, go to next step. If 1.25 volt or greater, go to step 21.
18. Turn ignition off and wait 10 seconds. Disconnect ECA and EVP sensor. Breakout box installed. With DVOM on 200 ohm scale, measure resistance from box pin 27 to pin 20, 40, 46 and 60 in turn. If 5 ohms or more, go to next step. If less than 5 ohms, repair short to ground in EVP signal circuit and repeat Self Test.
19. Turn ignition off. Breakout box installed and ECA and EVP sensor disconnected. With DVOM on 200 ohm scale, measure resistance from box pin 27 to EVP signal circuit at sensor harness. If 5 ohms or more, repair open in EVP signal circuit and repeat Self Test. If less than 5 ohms, go to step 20.
20. Turn ignition off. Replace EVP sensor with known good sensor and reconnect harness. Remove breakout box and reconnect ECA Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). If code 31 present, replace ECA and reinstall original EVP sensor. If no code 31, testing is complete.
21. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and connect breakout box. Leave ECA disconnected. Disconnect EVP sensor. With DVOM on 200 ohm scale, measure resistance from box pin 27 to pins 26, 37 and 57 in turn. If 5 ohms or more, go to next step. If less than 5 ohms, repair short to power and repeat «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test).
22. Turn ignition off and wait 10 seconds. Connect electrical harness to a known good EVP sensor and EGR valve assembly. Remove breakout box and reconnect ECA. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). If code 31, replace ECA, reconnect original EVP sensor and EGR valve assembly and repeat Self Test. If no code 31, go to step 23.
23. Turn ignition off and wait 10 seconds. Install original EVP sensor and connect harness. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test). If code 31, install new EVP sensor. If no code 31, testing complete.
24. Continuous Code 31. Disconnect vacuum line at EGR valve and install vacuum pump. Very slowly apply 6 in. Hg vacuum to sensor, then slowly bleed off vacuum. Enter Continuous Monitor mode and observe volt/ohmmeter for fault indication while doing the following: Lightly tap on EVP sensor to simulate road shock. Wiggle sensor connector. If fault is indicated, go to step 25. If no fault indicated, go to step 26. (Scheme 170): EGR Valve Position (EVP) Sensor Circuit
25. Turn ignition off and wait 20 seconds. Disconnect 60-pin connector at ECA and inspect. Repair as required. Connect breakout box and reconnect ECA. With volt/ohmmeter still connected to self-test output as in step 24, connect DVOM between box pin 27 and pin 46. Turn ignition on (engine off). With DVOM on 20 volt scale observe DVOM while repeating step 24. If fault occurs below 4.25 volts, disconnect and inspect harness at EVP sensor. If connector and terminals are okay, replace EVP sensor and repeat Self Test. If fault does not occur below 4.25 volts, EGR valve "overhoot"may have caused code 31. Sensor service not required. Go to step 26 to verity harness integrity.
26. Observe volt/ohmmeter while doing the following: Beginning at EVP, wiggle, shake or bend small sections of harness while working way to dash panel. Then repeating process from panel to ECA. If fault is indicated, isolate and repair problem and repeat Self Test. If no fault indicate, go to step 27.
27. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect connector and terminals for damage. If damaged, service as required and repeat Self Test. If okay, fault cannot be duplicated at this time. Continuous Code 31 testing is complete.

TEST EE - BRAKE ON/OFF (BOO)

1. Code 74. If brake was pressed during Engine Running Self Test, go to step 2 . If not, rerun Engine Running Self Test and press brake once during test.
2. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector. Inspect for damage, corrosion, loose wires, etc. Install breakout box and leave processor disconnected. Set DVOM on 20 volt scale. Measure voltage between test pin 2 and test pin 40 while depressing and releasing brake. If voltage cycles, replace processor. Repeat Self Test. If voltage does not cycle, repair brake circuit as necessary.
3. Code 75. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector. Inspect for damaged pins, corrosion, loose wires, etc. Repair as necessary. Install breakout box, leave processor disconnected. Set DVOM on 20 volt scale. Measure voltage between pin 2 and test pin 40 while depressing and releasing brake pedal. If voltage cycles, replace processor. Repeat Self Test. If voltage does not cycle, go to step 4 .
4. Turn key off. Breakout box installed and processor disconnected. Set DVOM on 200 ohm scale. Disconnect BOO circuit from harness 14290 (12 pin connector). Measure resistance between test pin 2 and ground. If resistance reading is greater than 5 ohms, service BOO circuit short to power. If resistance reading is less than 5 ohms, repair open in BOO circuit.

Brake On/Off (B00). Scheme 171

TEST FF - ERRATIC IGNITION

1. Code 14. Check EEC-IV and ignition systems harnesses for: Loose wires and connections. Arcing secondary ignition components (coil, cap, rotor, etc.). Faulty on-board transmitter (CB radio). If any faults are found, repair as necessary and repeat Self Test. If no faults are found, go to step 2 .
2. Turn key off and wait 10 seconds. Deactivate Self Test. Connect VOM or STAR. Enter Engine Running Continuous Test. Observe VOM or STAR LED display for indication of a fault while performing the following: Lightly tap and wiggle on TFI module and distributor. If fault is indicated, disconnect and inspect connectors. If connector and terminals are good, repair as necessary. If no fault is indicated, go to step 3 .
3. While still in Continuous Self Test from step 2 observe VOM or STAR LED for a fault indication while performing the following: While looking for faults grasp the harness close to the TFI connector. Wiggle, shake or bend a small section of the ignition and EEC-IV harness from the dash panel. Also wiggle, shake or bend the EEC-IV harness from the dash panel to the processor. Isolate the PIP circuit if needed for this test. If fault is indicated, isolate fault and repair as necessary. If no fault is found go to step 4 .
4. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector and inspect for damaged pins, corrosion, loose wires. If any fault is found, repair ignition system as necessary. Repeat Self Test.

TEST GG - IGNITION DIAGNOSTIC MONITOR (IDM)

1. Turn key off and wait 10 seconds. Disconnect E-core ignition connector from coil. Disconnect processor and inspect both 60 pin connectors for damaged pins, corrosion, loose wires, etc. If fault is found, repair as necessary and repeat Self Test. If no faults are found, go to step 2 .
2. Connect breakout box to harness and leave processor disconnected. Leave processor disconnected. Set DVOM on 200K scale. Measure resistance between test pin 4 and ignition coil negative terminal. If resistance reading less than 20K ohms or greater than 24K ohms, repair open circuit and repeat Self Test. If resistance reading is less than 24K ohms but greater than 20K ohms, go to step 3 .
3. Turn key off and wait 10 seconds. Leave breakout box installed and processor disconnected. Set DVOM on 200K ohm scale. Measure resistance between test pin 4 and test pins 40, 46 and 60. If resistance reading is less than 10K ohms, repair short to ground. Repeat Self Test. If resistance is 10K ohms or greater, go to step 4 .
4. Turn key off and wait 10 seconds. Deactivate Self Test. Connect VOM or STAR. Enter Engine Running Continuous Self Test. Observe VOM or STAR LED for indication of a fault while performing the following: Lightly tap and wiggle TFI connector. If fault is indicated, disconnect and inspect connectors. If connector and terminals are good, repair as necessary. If connector and terminals are not good, go to step 5 .
5. While still in continuous monitor test from step 1 observe VOM or STAR LED for a fault indication while performing the following: While looking for faults, grasp harness closed to the TFI connector. Wiggle, shake or bend a small section of the EEC-IV system harness while working your way to the dash panel. Also wiggle, shake or bend the EEC-IV harness from the dash panel to the processor. If no faults, go to step 6 .
6. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector and inspect for damaged pins, corrosion, loose wires. If connectors and terminals are okay and unable to duplicate an IDM fault in the EEC-IV system, testing is complete. If a fault is found, repair system as necessary. Repeat Self Test.

Ignition Diagnostic Monitor Circuit. Scheme 172

TEST HH - EGR ON/OFF CONTROL

1. Turn ignition off and wait 10 seconds. With DVOM on 200 ohm scale, disconnect EGR solenoid connector and measure solenoid resistance. If resistance is 65-110 ohms, connect EGR solenoid and go to next step. If resistance is less than 65 ohms or greater than 110 ohms, replace EGR solenoid and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
2. Turn ignition off and wait 10 seconds. Enter Output State Check and perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until end of Continuous code display. DVOM will indicate zero volts. Depress and release throttle and observe DVOM. If DVOM register high voltage, remain in Output State Check and go to next step. If DVOM did not register high voltage, depress throttle to wide open position and release. If voltage still does not register high reading, do to «TEST D - NO/WRONG CODES»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__test-d-nowrong-codes) , step 13).
3. Remain in Output State Check. With DVOM on 20 volt scale, connect positive test lead to vehicle power circuit on EGR solenoid and negative lead to EGR output circuit. While observing DVOM, depress and release throttle several times to cycle output on and off. If EGR output cycles on and off, go to step 4 . If EGR does not cycle on and off, go to step 6 .
4. Install vacuum pump to the solenoid vacuum supply port and install a vacuum gauge to output port. Apply and maintain minimum of 6 in. Hg. While depressing and releasing throttle to cycle output on and off, observe vacuum gauge. If output cycles on and off, go to step 5 . If vacuum output does not cycle on and off, replace solenoid and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
5. Remove all test equipment and disconnect vacuum lines at EGR solenoid. Start engine and check for vacuum at solenoid. If vacuum is present, EEC-IV system is functioning properly. If no vacuum is present, service vacuum source blockage or leak and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
6. Turn ignition on (engine off). With DVOM on 20 volt scale, connect positive lead to vehicle power circuit at solenoid and negative lead to ground. Measure voltage. If voltage reading is less than 10.5 volts, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If voltage reading is 10.5 volts or greater, go to step 7 .
7. Turn ignition off and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect for damaged pins, corrosion or loose wires and service as necessary. Leave ECA disconnected and connect breakout box to harness. With DVOM on 200 ohm scale, measure continuity from box pin 53 to EGR circuit at harness connector. If reading is 5 ohms or greater, repair open circuit and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is less than 5 ohms, go to step 8 .
8. Turn ignition off and wait 10 seconds. Breakout box installed and ECA and EGR solenoid disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 53 to pins 37 and 57. If reading is 10K ohms or greater, go to next step 9 . If reading is less than 10K ohms, repair short to power and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .
9. Turn ignition off and wait 10 seconds. Breakout box installed and ECA disconnected. With DVOM on 200K ohm scale, measure resistance from box pin 53 to pins 40, 46 and 60. If reading is less than 10K ohms, repair short to ground and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) . If reading is 10K ohms or greater, replace ECA and repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes) .

TEST II - WOT A/C CUTOFF (WAC) A/C DEMAND

Note. This test is intended to diagnose only the following: Harness circuits (WAC and V PWR). WOT A/C cut-off relay. Processor assembly. A/C demand switch. DO NOT use STAR tester for this step, use VOM/DVOM.

Scheme 173

1. Turn key off and wait 10 seconds. Set DVOM on 20 volt scale. Connect DVOM negative test lead to STO and positive test lead to battery positive. Jumper STI to signal return. Perform «KEY ON-ENGINE OFF (KOEO) SELF-TEST»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes__key-on-engine-off-koeo-self-test) until the completion of the Continuous Test Codes. The DVOM will indicate 0 volts, If DVOM reading changed to a high voltage reading, remain in Output state check and go to step 2. If not, depress throttle to WOT and release. If STO voltage does not go high, repair system as necessary.
2. Turn key on. Disconnect processor 60-pin connector and inspect for damaged pins, corrosion, loose wires. Repair system as necessary. Connect breakout box to harness and reconnect processor. Turn A/C switch on. Set DVOM on 20 volt scale. Connect DVOM positive test lead to test pin 37 and negative test lead to pin 54. While observing DVOM, depress and release the throttle several times. If A/C clutch output cycled on and off, EEC-IV system is okay. If not, go to step 3.
3. Turn key off and wait 10 seconds. Set DVOM on 200 ohm scale. Measure resistance between ground circuit and fan control module connector. If resistance reading is 5 ohms or greater, repair harness circuit. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If resistance reading is less than 5 ohms, go to step 4.
4. Turn key on. Set DVOM on 20 volt scale. Measure voltage between ignition circuit and ground circuit on the control module connector. If voltage is less than 10.5 volts, repair open in ignition circuit. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If voltage is 10.5 volts or greater. Go to step 5.
5. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector and inspect for damaged pins, corrosion, loose wires. Repair system as necessary. Connect breakout box to harness. Leave processor disconnected. Set DVOM on 200 ohm scale. Measure resistance between test pin 54 and WAC circuit at fan control module. If resistance is 5 ohm or greater, repair harness WAC circuit. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If resistance is less than 5 ohms, go to step 6.
6. Turn key off and wait 10 seconds. Leave breakout box installed and processor disconnected. Set DVOM on 200K ohm scale. Disconnect fan control module. Measure resistance between test pin 54 and test pins 40, 46 and 60. If all resistance readings are 10K ohms or greater, replace fan control module. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If resistance reading is less than 10K ohms, repair harness short. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
7. Turn key off and wait 10 seconds. Set DVOM on 200 ohm scale. Disconnect WAC relay connector and measure relay resistance. If resistance is between 50 and 70 ohms, connect WAG solenoid and go to step 9. If resistance is less than 50 ohms or greater than 70 ohms, replace WAC relay. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes).
8. Turn key on. Set DVOM on 20 volt scale. Connect DVOM positive test lead to V PWR circuit and negative test lead to ground. Measure voltage on Wac relay V PWR circuit. If voltage reading is less than 10.5 volts, repair harness open circuit. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If voltage reading is 10.5 volts or greater, go to step 10.
9. Turn key off and wait 10 seconds. Disconnect processor 60-pin connector and inspect for damaged pins, corrosion, loose wires. Repair system as necessary. Connect breakout box to harness. Leave processor disconnected. Set DVOM on 200 ohm scale. Measure resistance between test pin 54 and WAC circuit at harness connector. If resistance readings are 5 ohms or greater, repair harness open circuit Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If resistance readings are 5 ohms or less, go to step 11.
10. Turn key off and wait 10 seconds. Leave breakout box installed and processor disconnected. Set DVOM on 200K ohm scale. Measure resistance between test pin 54 and pins 40, 46 and 60. If resistance readings are less than 10K ohms, repair short to ground. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If resistance readings are 10K ohms or greater, go to step 12.
11. Turn key off and 10 seconds. Set DVOM on 200K scale. Leave breakout box installed and processor disconnected. Disconnect WAC solenoid. Measure resistance between test pin 54 and pins 37 and 57. If resistance reading is 10K ohms or greater, replace processor. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). If resistance reading is less than 10K ohms, service short to power. Repeat «QUICK TESTS»(/ford/cab-chassis-ranger/1985-1986/remont/testing-diagnostics/#50l58l-feedback-carburetor-tests-wcodes). (Scheme 173): WOT A/C Cutoff & (WAC) A/C Demand
12. Turn key off and wait 10 seconds. Disconnect processor 60 pin connector and inspect for damaged pins, corrosion, loose wires. Repair system as necessary. Connect breakout box to harness. Leave processor disconnected. Set DVOM on 20 volt scale. Measure voltage between test pin 10 and pin 40. If output cycles 4-10.5 volts when A/C switch is cycled, replace processor. If not, go to step 13.
13. Turn key off and wait 10 seconds. Set DVOM on 200 ohm scale. Measure resistance between AA//ACD test pin 10 and A/C clutch and A/C demand switch. If resistance reading is 5 ohms or greater, repair harness circuit. If resistance reading is less than 5 ohms, EEC-IV system is okay. End of test.

5.0L & 5.8L FBC EEC-IV Wiring Diagram (Except Van Models). Scheme 174

5.0L & 5.8L FBC EEC-IV Wiring Diagram (Van Models). Scheme 175

See also:
• Key On/Engine Off (KOEO) Self-Test
• KEY ON-ENGINE OFF (KOEO) SELF-TEST
• TIMING CHECK
• TEST D
• TEST E
• TEST F
• TEST G
• TEST M
• TEST S
• TEST Z
• TEST O
• TEST P
• TEST R
• TEST CC
• TEST T - SPARK TIMING CHECK
• TEST A - NO START
• TEST FF
• TEST K
• TEST I
• TEST EE
• TEST W
• TEST X - DIAGNOSIS BY SYMPTOM
• TEST II - WOT A/C CUTOFF (WAC) A/C DEMAND
• Output State Test
• TEST L - CANISTER PURGE TEST