2.2l Electronic Fuel Control Cec Dodge Caravan I

DESCRIPTION

Note. All 2.2L models use the Spark Control Computer with Spark Advance and Throttle Control systems. Only models with Holley 6520 carburetors use oxygen sensor feedback system.

The Electronic Fuel Control (EFC) system is an electronically controlled system that closely controls ignition timing and, on models with oxygen sensor feedback system, air/fuel ratio. The Spark Control Computer (SCC) is the heart of the system.

The SCC provides the capability of igniting a lean air/fuel mixture under various engine operating conditions. Also, during closed loop operation on models with feedback system, the computer maintains an air/fuel ratio close to the ideal 14.7:1.

TROUBLE CODE-TO-TEST MENU

TEST IDENTIFICATION CHART

OPERATION

The EFC system consists of 7 sub-systems: fuel control, spark control, throttle control, data sensors, Spark Control Computer (SCC), catalytic converter and self-diagnostic system.

Some models are equipped with a Holley 6550 carburetor. This model contains an electrically operated oxygen feedback solenoid. This solenoid meters the main fuel system of the carburetor and operates in parallel with conventional fixed main metering jets. The computer controls operation of the solenoid in response to signals received from data sensors, particularly the oxygen sensor. (Scheme 265)

Sectional View of Feedback Carburetor With Oxygen Feedback Solenoid. Scheme 265

When the solenoid is de-energized by the computer, the solenoid valve spring pushes upward through main system fuel valve. When de-energized, the solenoid main metering orifice is fully uncovered, providing the richest mixture for any given air flow.

When the solenoid is energized by the computer, the solenoid main metering orifice is fully sealed. This solenoid position offers the leanest mixture within the carburetor for any given air flow.

Main system fuel may be regulated between richest and leanest conditions by controlling the amount of time that the solenoid is energized and de-energized. The computer controls the duration of time that the solenoid is energized in comparison to total time of solenoid operation and in response to engine operating conditions and/or oxygen sensor signals. In this manner, the ideal air/fuel ratio can be constantly maintained.

SPARK CONTROL

Spark control allows the computer to determine the exact instant that ignition is required, then signals ignition coil to produce electrical impulses to fire the spark plugs. The computer eliminates the need for either vacuum advance units or centrifugal advance weights. Spark control operates in one of the following modes

Start Mode

During cranking, an electrical signal from the distributor is fed into the computer, which causes the computer to fire the spark plugs at a fixed amount of advance.

Run Mode

Once the engine starts and is operating normally, timing is controlled by the computer, based upon information received from the data sensors. Total spark advance is determined by 3 factors: coolant temperature, engine speed and manifold vacuum.

In a cold or warm engine, as indicated by coolant temperature sensor, RPM has no affect on advance. Under these conditions, the advance curve is determined by vacuum signal only. In a hot engine, computer is programmed to consider engine speed in addition to manifold vacuum, to determine total spark advance.

THROTTLE CONTROL

The throttle control system is used to maintain or raise engine speed for certain conditions. The conditions when engine speed is raised are during A/C operation or timer operation. There are 2 timers used in this system. When the engine is started, one timer provides a 2 second delay, during which engine speed is raised. Also, when throttle is closed, another timer prevents the throttle from immediately closing all the way.

Hall Effect Pick-up Assembly

This device is located in the distributor to supply a basic timing signal to the computer. The computer determines engine speed (RPM) based on this signal. (Scheme 294)

Location of Hall Effect Pick-Up Assembly in Distributor. Scheme 266

Coolant Sensor

This sensor is located on the thermostat housing and supplies a signal to the computer. Sensor resistance is inversely proportional to coolant temperature. This information is required to prevent air/fuel ratio from changing until engine reaches normal operating temperature. The computer also controls the amount of spark advance with a cold engine. (Scheme 300)

Location of Coolant Sensor. Scheme 267

Vacuum Transducer

The vacuum transducer is mounted on the computer and provides the computer with a signal of the amount of engine vacuum. Engine vacuum is used by the computer to determine how much to advance or retard ignition timing and to change air/fuel mixture.

Carburetor Switch

This switch is located on the end of the throttle kicker to signal the computer when the engine is at idle. (Scheme 282)

Location of Carburetor Switch. Scheme 268

Oxygen Sensor

This sensor, used with feedback system only, is located in the exhaust manifold to signal the computer of oxygen content of exhaust gases. The voltage output of the oxygen sensor is proportional to oxygen content of exhaust gases. The computer will adjust the air/fuel mixture (vary feedback solenoid timing) to a level which will maintain operating efficiency of the 3-way catalyst system and engine.

SPARK CONTROL COMPUTER

The computer is located on the left inner fender well, near battery. The computer consists of a printed circuit board which simultaneously receives signals from all data sensors and analyzes these signals to determine correct ignition timing and, on models with feedback system, air/fuel mixture. The air/fuel mixture is controlled in one of the following modes

Open Loop Mode

During cold engine operation, the air/fuel ratio is controlled by information programmed into the computer by the manufacturer. Until normal operating temperature is obtained, the air/fuel mixture will be fixed at a rich level to allow proper engine warm-up. During this mode of operation, air from the AIR pump is injected "upstream" in the exhaust manifold to assist in heating up the oxygen sensor.

Closed Loop Mode

Once normal engine operating temperature is reached, the air/fuel ratio is controlled by the computer based upon information received from the oxygen sensor.

Location of Spark Control Computer. Scheme 269

CATALYTIC CONVERTER

Proper emission control is accomplished with the catalytic converter system used with the EFC system. All models use a front converter with air injection line.

Note. Similarities exist between external characteristics of each converter system. However, extreme care must be exercised during replacement of converters due to internal design differences.

SELF-DIAGNOSTICS

The EFC system computer is programmed with self-diagnostic capabilities. The SCC constantly monitors the various engine systems and components. If a problem is detected in any monitored system, a "Fault Code" will be stored as an aid to system diagnosis.

If a detected problem is repaired, or fails to repeat within 20-40 ignition on/off cycles, the computer cancels the code. Stored fault codes may be recalled as an aid to complete system diagnosis by using Diagnostic Read-out Box (C-4805 ).

Removal & Installation

1. Remove battery. Disconnect 10-way and 14-way connectors from computer. Disconnect air duct and vacuum hose from vacuum transducer. NOTE: DO NOT remove grease from harness connectors or connector cavities in computer. Grease is used to prevent moisture from corroding terminals. If there is not at least l/8" of grease on bottom of computer connector cavities, apply a liberal amount of Mopar Multipurpose Grease (Part No. 2932524 ) over entire end of connector plug before reinstallation.
2. Remove 3 mounting screws holding computer to fender well. Remove computer. To install, reverse removal procedure.

Note. Computer is not serviceable. DO NOT attempt disassembly for any reason. If vacuum transducer is defective, replace entire computer.

Disconnect electrical connector and remove sensor. To install, coat sensor with anti-seize compound and reverse removal procedure.

Note. Hall Effect Pick-Up Assembly can only be replaced during overhaul of distributor.

Remove bracket and idle solenoid assembly from carburetor. Disconnect electrical connector. To install, reverse removal procedure.

Removal

1. Remove 2 solenoid retaining screws and gently lift solenoid from air horn. Remove anti-rattle spring, 2 retaining screws and idle solenoid from carburetor.
2. Remove 2 WOT cut-out switch mounting screws, if equipped. Mark location for proper assembly. Remove harness mounting screws and open retaining clip. Remove wires from connector and thread through clip.

Installation

1. Install idle solenoid and anti-rattle spring. Install WOT cut-out switch, if equipped. Adjust switch so A/C clutch circuit is open in throttle position of 10° before wide open throttle.
2. Install new O2 feedback solenoid gasket on air horn. Install new "O" ring on solenoid tip. Lightly lubricate solenoid with petroleum jelly. Install solenoid into carburetor. Install and tighten mounting screws. Route wiring through clamp and connect to harness. Install and tighten harness mounting screw.

1. Disconnect negative battery cable. Disconnect electrical lead from oxygen sensor and remove sensor.
2. Clean threads in exhaust manifold with 18mm x 1.5 x 16E tap. If old sensor is reinstalled, coat threads with anti-seize compound. New sensors have compound already applied. Hand start sensor, then tighten to 20 ft. lbs. (27 N.m). Connect electrical connector and battery cable.

DIAGNOSIS & TESTING

A malfunction in the EFC system may result in engine surge, hesitation, rough idle and/or poor fuel economy. Before making any tests, check all vacuum and electrical wiring for proper routing and connections, and check for exhaust and intake manifold leaks. If these are in order, testing may begin.

The Spark Control Computer controls ignition timing and air/fuel mixture (with feedback system). When system testing is required, always perform ELECTRONIC SPARK CONTROL TESTS first, before testing EFC system, or using the On-Board Diagnostic system.

When testing requires that either harness connector be disconnected from the computer, DO NOT remove grease from either connector or cavities in computer. The grease is used in order to prevent moisture from corroding the terminals. If there is not at least 1/8" of grease on bottom of computer connector cavities, apply a liberal amount of Mopar Multipurpose Grease (Part No. 2932524 ) over entire end of plug before reinstalling.

Ignition System Starting Test

1. Remove coil secondary wire from distributor cap. Hold end of wire 1/4" away from good engine ground. Have an assistant crank engine, while you watch for spark at secondary wire. Spark should be constant and bright blue.
2. If spark is constant and bright blue, have assistant continue to crank engine and watch for arcing at coil tower while slowly moving coil secondary wire away from good ground. If arcing occurs, replace coil. If spark is weak or inconsistent, or there is no spark, proceed to FAILURE TO START TEST.
3. If spark is good and there is no arcing at the coil tower, secondary voltage is satisfactory. Make sure it is reaching spark plugs by checking distributor rotor, cap, spark plug wires and spark plugs. If all of these components check okay, ignition system is not at fault. Check fuel system or the engine for mechanical damage.

Scheme 270

Scheme 271

1. Measure and record battery voltage. Check battery specific gravity, which must be 1.220 (temperature corrected) to deliver proper voltage to ignition system.
2. Remove coil secondary wire from distributor cap and hold 1/4" from a good ground. Prepare a special jumper wire assembly. (Scheme 277) With the ignition on, momentarily touch special jumper wire to ground and coil negative terminal. A spark should be obtained at the coil secondary wire. (Scheme 270): Special Jumper Wire Assembly For Testing Ignition Coil
3. If spark was obtained, proceed to step 6). If no spark resulted, turn ignition off and disconnect 10-way harness connector from computer. (Scheme 283) Turn ignition on. Using special jumper wire, connect negative terminal momentarily to ground. Spark should be obtained.
4. If spark was obtained, but engine will not start, computer output is shorted. Replace computer. If no spark resulted in step 3), connect positive lead of voltmeter to coil positive terminal and negative lead to a good ground. Voltage reading should be within 1 volt of battery voltage. If not, check wiring between battery and coil positive terminal.
5. If correct voltage was recorded in step 4), measure voltage between ground and coil negative terminal. Voltage reading should be within 1 volt of battery voltage. Replace ignition coil if there is either no voltage present, or if voltage is present but no spark results when shorting negative coil terminal. (Scheme 271): Distributor & Computer Harness Connectors Used to Test System
6. If spark was obtained in step 2), or if in step 5), voltage was obtained but engine would not start, hold carburetor switch open with a thin cardboard insulator. Measure voltage between carburetor switch and ground. Reading should be within 1 volt of battery voltage. If voltage reading is okay, proceed to step 10).
7. If voltage was incorrect in step 6), turn ignition off and disconnect 10-way harness connector from computer. Turn ignition on. Connect positive lead of voltmeter to cavity "2" of connector and negative lead to ground. Reading should be within 1 volt of battery voltage.
8. If no battery voltage is present, check wire from battery to ignition switch to cavity "2". Use an ohmmeter if necessary, to check continuity of wires. Correct problem and repeat step 7). If voltage was present in step 7), turn ignition off and connect ohmmeter leads to carburetor switch terminal and cavity "7" of 10-way connector.
9. If no continuity is found, check for open wire between cavity "7" and carburetor switch. If continuity was indicated, connect ohmmeter leads to cavity "10" and to a good ground. If continuity exists, replace computer, as correct power is entering computer, but not leaving it. Repeat step 6). If no continuity existed between cavity "10" and ground, check for an open wire in the ground system.
10. Reconnect 10-way harness connector to computer. Turn ignition on and hold secondary coil wire 1/4" from a good ground. Disconnect 3-way distributor connector from distributor. Attach jumper wire between cavities "2" and "3" of harness connector. A good spark should jump from coil wire to ground.
11. If spark resulted, but engine will not start, replace Hall Effect Pick-up. If no spark resulted in step 10), connect voltmeter positive lead to distributor harness connector cavity "1" and negative lead to ground. Reading should be within 1 volt of battery voltage. If no battery voltage is present, proceed to step 14). If voltage was correct, turn ignition off and disconnect 10-way harness connector from computer.
12. Connect ohmmeter leads between cavity "2" (Black/Light Blue wires) of distributor harness connector and cavity "9" of 10-way connector. Then connect leads to cavity "3" (Gray wire) of distributor harness connector and cavity "5" of 10-way connector.
13. If no continuity is present, repair open wires. If continuity exists, replace computer (power going into computer, but not coming out). Repeat step 10).
14. If there was no battery voltage in step 11), turn ignition off. Disconnect 10-way connector and connect ohmmeter leads to cavity "1" of distributor harness and cavity "3" of 10-way connector. If no continuity exists, repair wire and repeat step 10).
15. If continuity existed in step 14), turn ignition on and check for battery voltage with voltmeter positive lead in cavity "2" of 10-way connector and negative lead in cavity "10". If battery voltage is present, but vehicle will not start, replace computer and repeat step 10). If no battery voltage is present, check ground wire and repeat step 10).

Spark Control Computer Spark Test

1. Bring engine to normal operating temperature ensure that basic ignition timing is properly adjusted. Ensure coolant temperature sensor is connected and working properly.
2. Remove and plug vacuum hose at vacuum transducer. Connect a vacuum pump to vacuum transducer and apply 16 in. Hg vacuum. Increase engine speed to 2000 RPM and wait 1 minute before checking specifications. See «SPARK ADVANCE TEST SPECIFICATIONS»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) table. Specifications given in table are TOTAL advance (initial advance is included). If computer fails to obtain settings, replace computer.

SPARK ADVANCE TEST SPECIFICATIONS (1)

ELECTRONIC THROTTLE CONTROL SYSTEM TEST

1. Connect a tachometer to engine. Start and run engine until it reaches normal operating temperature. Depress accelerator, then release. Engine speed should not immediately return to idle. On vehicles equipped with A/C, a slight increase in idle speed should be observed while A/C is in operation.
2. Turning off A/C will return idle speed to normal. As the A/C clutch cycles on and off, the throttle kicker solenoid plunger should extend and retract. If plunger does not move with clutch cycling, or after engine starts, check the kicker system for vacuum leaks. If engine speed does not increase as specified, disconnect the 6-way connector at carburetor.
3. Connect ohmmeter leads from ground to solenoid terminal that was connected to Black wire. Resistance should be 20-100 ohms. If not, replace solenoid. Reconnect solenoid. Start vehicle and immediately (before 2 second time delay times out) measure voltage across vacuum solenoid terminals.
4. Voltage should be within 2 volts of charging system voltage. If not, replace computer. Turn on A/C after time delay has timed out. Charging voltage should once again be present at solenoid. If not, check wiring back to instrument panel for open circuit.

ELECTRONIC FUEL CONTROL SYSTEM TESTS

Note. The SPARK CONTROL COMPUTER SPARK TEST should be made prior to beginning any test on EFC system. The following tests should be performed in the sequence given. Ensure basic timing and hot curb idle speed are set to specifications before testing.

Carburetor Switch Test

1. With the engine at normal operating temperature, turn the ignition off and disconnect 10-way connector from computer. With throttle completely closed, check continuity with ohmmeter leads connected to cavity "7" and ground. NOTE: Grounding carburetor switch eliminates spark advance on most systems and provides fixed air/fuel ratio on feedback carburetor systems.
2. If there is no continuity, check wire from cavity "7" to carburetor switch terminal. Also check carburetor switch for proper operation. Open throttle and check for continuity from cavity "7" to ground. There should be no continuity. If readings are not as outlined, replace carburetor switch.

Coolant Sensor Test

Turn ignition off and disconnect wire connector from coolant sensor. Connect ohmmeter leads between coolant sensor terminals. Coolant temperature of 70°F (21°C) should show 5000-6000 ohms. Coolant temperature of 200°F (93°C) should show 700-800 ohms. If not, replace sensor.

ON-BOARD DIAGNOSTICS

The Monitor 2000 is used to recall stored codes. The read-out box can be used to check 4 different system modes. These are: Diagnostic Test Mode, Circuit Actuation Test Mode (ATM test), Sensor Test Mode and Switch Test Mode.

The Diagnostic Test Mode is used to retrieve fault codes that may be stored in the computer. The Circuit Actuation Test Mode (ATM Test) is used to check out specific component systems. The Sensor Test Mode is used to check the output signals of the sensors as received by the computer. Sensor access codes are used in this mode. The Switch Test Mode is used to determine if specific switch inputs are being received by the computer.

Scheme 272

1. Connect diagnostic read-out box to connector at left shock tower and move read/hold switch to "READ" position. (Scheme 284)
2. Ensure that carburetor switch is open by placing fast idle screw on highest step. Turn ignition switch to run position. Wait for code "00" to appear on read-out box. (Scheme 272): Diagnostic Read-Out Box (C-4805)
3. Move hold/read switch to "HOLD" position and record any codes that are displayed. Read-out may be stopped at any time by moving switch to "READ" position, then back to "HOLD" position when ready to continue read-out.
4. Before using indicated trouble code charts, perform a careful visual check of all wiring and vacuum connections in the indicated system (many problems are the result of loose, disconnected, or misconnected wires or vacuum hoses). If these components are in good condition and properly connected, use respective charts to complete diagnosis of system fault. See «EFC FAULT CODE IDENTIFICATION»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) table to interpret stored codes.

EFC FAULT CODE IDENTIFICATION

Circuit Actuation Test Mode (ATM)

1. Run system through Diagnostic Test Mode and wait for code "55" to display. Press ATM button on read-out box to activate display. ATM test codes will appear on read-out box. Hold button down until desired display appears.
2. The Spark Control Computer will turn selected circuit on and off for up to 5 minutes, or until ATM button is pressed again (or ignition is turned off). If ATM button is not pressed again, the Spark Control Computer will shut system off after 5 minutes.

ATM TEST DISPLAY CODES

Sensor Test Mode

1. Run the system through the ATM Test Mode. Press and hold the ATM test button until the desired test code appears on the read-out box display. Release the ATM button. Move the Read/Hold switch to the "Hold" position. NOTE: Since sensor access codes are the same as some ATM test codes, the ATM test circuit will turn on before the Read/Hold switch is moved to the "Hold" position.
2. The computer will now use the diagnostic read-out box to display the output of the selected sensor.

SENSOR TEST MODES

Switch Test Mode

1. Run system through Diagnostic Test Mode and wait for code "55" to display. Ensure that both air conditioning and rear window defogger are off. Press ATM button and immediately move read/hold switch to "READ" position.
2. Wait for code "00" to display. Turn A/C switch on. If computer is receiving input, display will change to "88" when switch is turned on and back to "00" when switch is turned off.

NS1 - CHECKING FOR SPARK AT SPARK PLUGS

Remove any spark plug wire and insert a screwdriver into the terminal. Position screwdriver 1/4" from a good ground. Have an assistant crank the engine. There should be a good spark between the screwdriver and ground. If there is a good spark, proceed to NS2 . If there is no spark, proceed to NS5 .

NS2 - CHECKING FOR FUEL IN CARBURETOR

Remove air cleaner cover. Open throttle several times while watching for fuel spray from the accelerator pump discharge nozzle. If fuel spray is okay, proceed to NS3 . If there is no fuel spray, proceed to NS7 .

NS3 - CHECKING FOR FUEL FOULED SPARK PLUGS

Remove the spark plugs. The spark plugs should be dry. If spark plugs are okay, proceed to NS4 . If spark plugs are wet with fuel, clean and reinstall. Check for gasoline in the crankcase. Change oil and filter as necessary.

NS4 - ENGINE TIMING CHECK

Connect a timing light to the engine. Have an assistant crank the engine while you observe the timing marks. Timing should be 0-16° BTDC. If timing is okay, check compression and valve timing. If timing is not okay, set timing to 10° BTDC while cranking. Engine should start. If engine starts, reset timing to specification. If engine does not start, check compression and valve timing.

NS5 - CHECKING FOR SPARK AT COIL WIRE

1. Disconnect coil wire from the distributor cap. Hold the coil wire terminal 1/4" from a good ground. Crank the engine. There should be spark between the coil wire terminal and ground. If there is spark, problem is in distributor cap, rotor or spark plug wires. Repair or replace as necessary.
2. If there is no spark, disconnect ignition coil wire from the coil. Connect an ohmmeter between the terminals of the coil wire. Ohmmeter reading should be 250-600 ohms per INCH or 3000-7200 ohms per foot. If resistance is okay, proceed to «NS6»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__ns6-checking-primary-ignition-system) . If resistance is not okay, replace the coil wire.

NS6 - CHECKING PRIMARY IGNITION SYSTEM FOR FAULT CODES

1. Connect diagnostic read-out box to the engine harness connector. Put the system into the "Diagnostic Mode". Record all codes. If Code 14 is displayed, proceed to step 2). If Code 21, or Codes 21 and 31 are displayed, proceed to step 5). If there is no Code 88, proceed to step 10).
2. Connect an ohmmeter between the ignition coil positive and negative terminals. Ohmmeter reading should be 1.6-1.8 ohms. If resistance is not okay, replace the coil. If resistance is okay, disconnect the ignition coil wire from the coil. Connect ohmmeter between between the coil negative and the secondary terminals.
3. Ohmmeter reading should be 9400-11,700 ohms. If resistance is not within specifications, replace the ignition coil. If resistance is okay, check coil with a load tester. If coil tests okay, disconnect the 10-way connector from the computer. Connect a voltmeter between connector cavity "1" and ground. Turn the ignition switch to the "RUN" position.
4. Voltage reading should be within one volt of battery voltage. If voltage reading is okay, check terminal in connector cavity "1" to ensure it is not spread apart causing a poor connection. If connection is okay, replace the computer. If voltage reading was not okay, repair primary circuit to the ignition switch for an open or short circuit.
5. Disconnect the distributor harness connector. Turn the ignition switch to the "RUN" position. Disconnect the coil wire at the distributor and place it 1/4" from a good ground. Connect a jumper lead between terminals "2" and "3" of the distributor harness connector. Make and break this connection several times. There should be a spark from the coil wire to ground.
6. If there is no spark, proceed to step 8). If spark is okay, connect a voltmeter to the distributor engine harness connector cavity "1" and ground. Voltage reading should be within one volt of battery voltage. If voltage reading is okay, replace the distributor pick-up assembly. If there is zero volts, turn the ignition off.
7. Disconnect the computer 10-way connector. Connect an ohmmeter between the computer connector cavity "3" and the distributor harness connector cavity "1". Ohmmeter should show continuity. If there is continuity, ensure terminals in computer connector cavity "3" and distributor harness connector cavity "1" are not spread apart causing a poor connection. If connections are okay, replace the computer. If there is no continuity, repair wiring between computer connector cavity "3" and distributor harness connector cavity "1" for an open circuit.
8. With the ignition off, connect ohmmeter between 10-way connector cavity "9" and distributor harness connector cavity "2". Ohmmeter should show continuity. If there is continuity, proceed to step 9). If there is no continuity, repair wiring between computer connector cavity "9" and distributor harness connector cavity "2".
9. Connect ohmmeter between 10-way connector cavity "5" and the distributor harness connector cavity "3". Ohmmeter should show continuity. If there is continuity, check terminal in 10-way connector cavity "5" to ensure it is not spread apart causing a poor connection. If connection is okay, replace the computer. If there is no continuity, repair wiring between computer 10-way connector cavity "5" and distributor harness connector cavity "3" for an open circuit.
10. Turn the ignition off. Ensure the diagnostic read-out box is operational. Disconnect the 10-way connector from the computer. Connect a voltmeter between the 10-way connector cavity "2" and ground. Turn the ignition switch to the "RUN" position. Voltage reading should be within one volt of battery voltage. If voltage reading is okay, proceed to step 11). If voltage is not okay, repair wire to connector cavity "2" for an open circuit to the ignition switch.
11. Turn the ignition off. Connect ohmmeter to 10-way connector cavity "10" and ground. Ohmmeter should show continuity. If there is continuity, ensure terminal in connector cavity "10" is not spread apart causing a poor connection. If connection is okay, replace the computer. If there is no continuity, repair wire to connector cavity "10" for an open circuit.

NS7 - CHECKING FUEL PUMP

1. Connect a fuel pump pressure gauge to the fuel line at the carburetor. Crank the engine for at least 10 seconds. Fuel pump pressure should be 1-4 psi. If fuel pressure is okay, repair the fuel inlet circuit of the carburetor. If fuel pressure is not okay, remove pressure gauge and reconnect fuel line to the carburetor.
2. Connect fuel pressure gauge to the fuel line before the fuel filter. Crank the engine for at least 5 seconds. Fuel pressure should be 1-4 psi. If fuel pressure is okay, replace the fuel filter. If fuel pressure is not okay, disconnect pressure gauge from the fuel line.
3. Connect a vacuum gauge to the fuel pump inlet line. Crank engine for at least 10 seconds. Vacuum reading should be at least 10 in. Hg vacuum. If vacuum is okay, check for plugged or restricted fuel lines, proper fuel tank venting or a clogged in-tank filter. If vacuum is not okay, replace fuel pump.

Diagnostic Readout Box. Scheme 273

DR1 - CHECKING DIAGNOSTIC SYSTEM FOR FAULT CODES

1. Connect diagnostic read-out box to engine harness connector. Put system into "Diagnostic Mode". Record all codes. NOTE: If fault codes 22, 28, 25 or 26 are stored, proceed to test indication.
2. Turn the ignition off. Disconnect computer 14-way connector for one minute, then reconnect it. Disconnect the diagnostic read-out box. Start engine and run for 2 minutes. Turn the ignition off. Reconnect the diagnostic readout box. Put system into "Diagnostic Mode". Record all codes.
3. If same code appears before and after engine is started, problem still exists. Proceed to test indications. If a code does not reappear after engine is run and turned off, code no longer exists (was intermittent). Check for loose or corroded wiring connections in circuit. Use wiring diagram as a guide.

TEST IDENTIFICATION CHART

Scheme 274

Scheme 275

Scheme 276

Scheme 277

1. Be sure diagnostic readout box is connected to engine harness connector. Put system in ATM test mode. Press and hold ATM button until first test code (91) appears.
2. TEST CODE 91. O2 solenoid should be heard clicking. If okay, press and hold ATM button until next test code appears. If not, replace O2 solenoid. (Scheme 274): Checking Computer Controlled Components (Dakota( (1 of 4)
3. TEST CODE 92. (Manual transmission models only.) Shift indicator Light (S.I.L.) should be blinking. If okay, press and hold ATM button until next test code appears. If not, S.I.L. circuit requires replacement.
4. TEST CODE 93. Turn ignition switch on. V.O.S. control solenoid should be heard clicking. If okay, turn ignition switch off and press and hold ATM button until next test code appears. If V.O.S. does not click, replacement is required.
5. TEST CODE 96. Radiator fan should be turning on and off. If okay, press and hold ATM button until next test code appears and go to step 10). If fan does not turn on and off, but really is clicking, connect jumper wire from terminal No. 1 to terminal No. 5 of radiator fan relay. If fan cycles on and off, repair wire from terminal No. 1 of radiator fan relay for an open circuit. If fan does not cycle, repair circuit to radiator fan motor. (Scheme 275): Checking Computer Controlled Components (Dakota) (2 of 4)
6. If fan runs continuously, disconnect computer 10-way connector. If fan stops, computer requires replacement. If fan continues to run, repair wire from terminal No. 4 of radiator fan relay to pin No. 8 of computer 10-way connector for a short to ground.
7. If relay does not click, connect voltmeter between terminal No. 4 of radiator fan relay and ground. If voltmeter is within one volt of battery voltage, go to next step. If not, go to step 9).
8. Turn ignition off. Disconnect computer 10-way connector. Connect voltmeter to cavity No. 8 of 10-way connector and ground. Turn ignition on. If voltmeter is within one volt of battery voltage, replace computer. If voltmeter is not within one volt, repair wire of cavity No. 8 for an open circuit to radiator fan relay. (Scheme 276): Checking Computer Controlled Components (Dakota (3 of 4)
9. Connect jumper wire from terminal No. 1 to terminal No. 5 of radiator fan relay. If fan cycles on and off, repair wire from terminal No. 5 of radiator fan relay to wiring harness splice for an open circuit. If fan does not cycle, replace fan relay. (Scheme 277): Checking Computer Controlled Components (Dakota) (4 of 4)
10. TEST CODE 97. Electric throttle control solenoid should be clicking. If okay, press and hold ATM button until next test code appears. If not, replacement is required.
11. TEST CODE 98. Canister purge solenoid should be clicking. If canister purge solenoid is a cold problem, go to DR13. If canister purge solenoid is a warm problem, go to DR21. If canister purge solenoid does not click, replacement is required.

Scheme 278

Scheme 279

Scheme 280

Scheme 281

1. Connect diagnostic readout box to engine harness connector. Put system into "ATM Test Mode 91". O2 solenoid is clicking, press and hold ATM button until Test code 92 appears. Proceed to next step. If O2 solenoid is not clicking, replace solenoid.
2. This step is used only on vehicles with manual transmissions. Shift indicator light (S.I.L.) is not blinking repair circuit as necessary.
3. The V.O.S. control solenoid should be clicking. If V.O.S. control solenoid is clicking, turn ignition off. Press and hold ATM button until Test Code 96 appears. Proceed to next step. If V.O.S. control solenoid is not clicking, replace solenoid.
4. Radiator coding fan should be cycling on and off. If radiator cooling fan is cycling on and off, press and hold ATM button until Test code 97 appears and proceed to step 9). If cooling fan does not cycle on and off and relay clicks, proceed to next step.
5. Disconnect radiator fan motor harness connector and reconnect Green wire. Connect jumper wire from Black wire of radiator fan not reconnector and ground. If fan now cycles on and off, repair Black wire from harness connector for open circuit. If fan does not cycle, go to next step. (Scheme 278): Computer Controlled Components Check (All Others, 1 of 4)
6. Connect a jumper lead between radiator cooling fan relay terminals No. "1" and "2", fan should cycle on and off. If fan cycles on and off, repair wiring to relay terminal No. "1" from engine harness splice for an open circuit. If fan does not cycle on and off, go to next step. (Scheme 279): Computer Controlled Components Check (All Others, 2 of 4)
7. Disconnect 3-way connector from relay. Connect jumper wire to Green wire at relay. Touch other end of jumper wire to positive post of car battery. If fan turns, replace fan relay. If not, go to next step. (Scheme 280): Computer Controlled Components Check (All Others, 3 of 4)
8. Disconnect radiator fan motor connector and reconnect Black wire. Connect one end of jumper wire to open terminal of radiator fan motor harness. Touch other end of jumper wire to positive post of car battery. If fan turns, repair Green wire from radiator fan relay for an open circuit. If not, fan motor should be replaced. (Scheme 281): Computer Controlled Components Check (All Others, 4 of 4)
9. The electronic throttle control solenoid should be clicking. If electronic throttle control solenoid is clicking, press and hold ATM button until Test code 98 appears. Proceed to next step. If electronic throttle control solenoid does not click, replace solenoid.
10. The canister purge solenoid should be clicking. If canister purge solenoid does not click, replace solenoid. If canister purge solenoid is clicking and driveability problem occurs when engine is cold, proceed to DR13. If solenoid is clicking and driveability problem occurs when engine is at normal operating temperature, proceed to DR21.

Scheme 282

1. Be sure readout box is connected to engine harness connector. Connect voltmeter to Green O2 solenoid wire at carburetor 6-way connector and ground. Put system in "Test Mode 91". If voltmeter pulsates between 0-1 volt, replace O2 solenoid. If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 3). (Scheme 282): O2 Solenoid Circuit (Dakota)
2. Turn ignition off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 12 of 14-way connector and ground. Turn ignition switch to "RUN" position. If voltmeter reading is within one volt of battery voltage, replace computer. If voltmeter reading is not within one volt of battery voltage, repair wire of cavity No. 12 for an open circuit to the O2 solenoid.
3. Turn ignition switch off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltmeter reading is within one volt of battery voltage, replace computer. If voltmeter reading is still 0-1 volt, repair Green O2 solenoid wire for a short to ground.

Scheme 283

Scheme 284

Scheme 285

1. Connect diagnostic readout box to engine harness connector. Ensure carburetor switch is open, ignition switch is in "RUN" position and read/hold switch is in "Hold" position. Wait for code 55 to display.
2. Connect a voltmeter to Green oxygen solenoid wire at carburetor 6-way connector and ground. Press and hold ATM button until code 91 appears on display. If voltmeter reading is pulsating and solenoid is clicking, check for poor connection in harness circuit. if voltmeter is not pulsating but reads within one volt of battery voltage, proceed to step 4). (Scheme 283): O2 Solenoid Circuit (All Other Models) (1 of 4)
3. If voltmeter is not pulsating but reads 0-1 volt, disconnect computer 14-way connector. If voltage is now within one volt of battery voltage, replace computer. If not, proceed to step 6).
4. Turn ignition off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. "12" of 14-way connector and ground. Turn ignition switch to "RUN" position.
5. Voltmeter should within one volt of battery voltage. If voltage is okay, ensure terminal in connect cavity No. "12" is not spread apart causing a poor connection. If connection is okay, replace computer. If not, inspect wire from cavity No. "12" to oxygen solenoid for open circuit and repair is needed.
6. Be sure voltmeter is still connect to Green O2 solenoid wire. Turn ignition off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltmeter reading is within one volt of battery voltage, computer should be replaced. If reading is not within one volt, repair Green O2 sensor wire for a short to ground.
7. Inspection for fault code 13. Connect voltmeter to Black wire of carburetor 6-way connector and ground. Be sure system is in test code 93 mode. If voltmeter pulsates between 0-2 volts, replace V.O.S. control solenoid. If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 9). (Scheme 284): O2 Solenoid Circuit (All Other Models) (2 of 4)
8. Connect diagnostic readout box to engine harness connector. Connect voltmeter to Black wire of carburetor, 6-way connector and ground. Put system in "ATM Test Mode 93." If voltmeter pulsates between 0-2 volts, replace VOS control solenoid. If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, perform step 10).
9. Turn ignition switch off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 13 or 14-way connector and ground. Turn ignition switch to "RUn" position. If voltmeter is within one volt of battery voltage, check terminals in cavity No. 13 for damage. If okay, replace computer. If voltmeter is not within one volt of battery voltage repair wire of cavity No. 13 for an open circuit to V.O.S. control solenoid. (Scheme 285): O2 Solenoid Circuit (All Other Models) (3 of 4)
10. Be sure voltmeter is still connected to Black V.O.S. solenoid wire. Turn ignition switch off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltmeter reading is within one volt of battery voltage, computer should be replaced. If voltmeter is not within one volt of battery voltage, repair Black V.O.S. control solenoid wire for short to ground.

O2 Solenoid Circuit (All Other Models (4 of 4). Scheme 286

Scheme 287

Scheme 288

1. Be sure readout box is connected to engine harness connector. Connect voltmeter to Black wire to carburetor 6-way connector and ground. Put system in "Test Mode 93". If voltmeter pulsates between 0-2 volts, replace V.O.S. solenoid. If voltmeter is not pulsating, but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 3). (Scheme 287): V.O. S. Control solenoid (2.2L Dakota) (1 of 2)
2. Turn ignition switch off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 13 of the 14-way connector and ground. Turn ignition switch to "RUN" position. If voltmeter reading is within one volt of battery voltage, replace computer. If voltmeter is not within one volt of battery voltage, repair wire of cavity No. 13 for an open circuit to the V.O.S. control solenoid. (Scheme 288): V.O. S. Control solenoid (2.2L Dakota) (2 of 2)
3. Turn ignition switch off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltmeter reads within one volt of battery voltage, computer requires replacement. If voltmeter reading is still 0-1 volt, repair Pink wire of cavity No. 13 of computer 14-way connector for a short to ground.

Scheme 289

Scheme 290

Scheme 291

Scheme 292

1. Be sure diagnostic readout box is connected to engine harness connector. Connect voltmeter to Dark Blue/White wire of terminal No. 4 of radiator fan relay and ground. Put system in "Test mode 96." If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter pulsates between 0-2 volts, go to step 3). If voltmeter is not pulsating but reads 0-1 volt, go to step 5). (Scheme 289): Radiator Fan Relay System (Voyager/Caravan/Ram Vans, 1 of 4)
2. Turn ignition off. Disconnect computer 10-way connector. Connect voltmeter to cavity No. 8 of 10-way connector and ground. Turn ignition switch to "RUN" position. If voltmeter is within one volt of battery voltage and terminals are undamaged, computer should be replaced. If voltmeter is not within one volt of battery voltage, repair wire of cavity No. 8 for an open circuit to radiator fan delay. (Scheme 290): Radiator Fan Relay System (Voyager/Caravan/Ram Vans, 2 of 4)
3. Connect jumper wire from terminal No. 1 to terminal No. 2 of radiator fan relay. If fan relay cycles on and off, repair wire from terminal No. 2 of radiator fan relay to wiring harness splice for an open circuit. If fan relay does not cycle, go to next step. (Scheme 291): Radiator Fan Relay System (Voyager/Caravan/Ram Vans, 3 of 4)
4. Connect voltmeter between terminal No. 1 and ground. If voltmeter reads within one volt of battery, relay should be replaced. If voltmeter does not read within one volt of battery, wiring harness should be repaired for an open circuit. (Scheme 292): Radiator Fan Relay System (Voyager/Caravan/Ram Vans, 4 of 4)
5. Disconnect computer 10-way connector. If voltmeter reading is within one volt of battery voltage, computer should be replaced. If voltmeter reading is not within one volt of battery voltage, repair Dark Blue/White wire of terminal No. 4 of relay for a short to ground.

Scheme 293

Scheme 294

1. Be sure diagnostic readout box is connected to engine harness connector. Connect voltmeter to Green wire with White tracer of dual solenoid 3-way connector and ground. Put system in "Test Mode 97". If voltmeter pulsates between 0-2 volts, replace throttle control solenoid. If voltmeter is not pulsating but reads within one volt of battery, voltage go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 3). (Scheme 293): Throttle Control Solenoid Circuit (Dakota) (1 of 2)
2. Turn ignition off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 6 of 14 way connector and ground. Turn ignition switch to "RUN" position. If voltmeter reading is within one volt of battery voltage and computer terminals are okay, computer should be replaced. If voltmeter reading is not within one volt of battery voltage, repair wire of cavity No. 6 for an open circuit to throttle control vacuum solenoid. (Scheme 294): Throttle Control Solenoid Circuit (Dakota) (2 of 2)
3. Turn ignition off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltmeter is within one volt of battery voltage, computer should be replaced. If voltmeter still reads 0-1 volts, repair Green/White wire for a short to ground.

Scheme 295

Scheme 296

1. Be sure diagnostic readout box is connected to engine harness connector. Connect voltmeter to Green wire of throttle control solenoid connector and ground. Put system in"Test Mode 97". If voltmeter pulsates between 0-2 volts, replace throttle control solenoid. If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 3). (Scheme 295): Throttle Control Solenoid Circuit (All Others, 1 of 3)
2. Turn ignition off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 6 of 14-way connector and ground. Turn ignition switch to "RUN" position. If voltmeter reads within one volt of battery voltage and computer terminals are okay, computer should be replaced. If voltmeter reading is not within one volt of battery voltage, repair wire of cavity No. 6 for an open circuit to throttle control vacuum solenoid. (Scheme 296): Throttle Control Solenoid Circuit (All Others, 2 of 3)
3. Turn ignition switch off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltage reading is within one volt of battery voltage, replace computer. If voltmeter reading is not within one volt of battery voltage, repair. Green throttle control solenoid wire for short to ground.

Throttle Control Solenoid Circuit (All Others, 3 of 3). Scheme 297

Scheme 298

Scheme 299

1. Connect voltmeter to Gray wire of dual solenoid 3-way connector and ground. Put system in "Test Mode 98". If voltmeter pulsates between 0-2 volts, replace canister purge solenoid. If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 3). (Scheme 298): Canister Pulse Solenoid Circuit (Dakota) (1 of 2)
2. Turn ignition off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 8 of 14-way connector and ground. Turn ignition switch to "RUN" position. If voltmeter is within one volt of battery voltage and computer terminals are okay, computer should be replaced. If voltmeter is not within one volt of battery voltage, repair wire of cavity No. 8 for an open circuit to canister purge control solenoid. (Scheme 299): Canister Pulse Solenoid Circuit (Dakota) (2 of 2)
3. Turn ignition switch off. Disconnect 14-way connector. Turn ignition switch to "RUN" position. If voltmeter is within one volt of battery voltage, computer should be replaced. If voltmeter is not within one volt of battery voltage, repair canister purge solenoid control wire (Green/Yellow) for a short to ground.

Scheme 300

Scheme 301

1. Be sure diagnostic readout box is still connected to engine harness connector. Connect voltmeter to green/Yellow wire of canister purge solenoid connector and ground. Put system in "Test mode 98." If voltmeter pulsates between 0-2 volts, replace canister purge solenoid. If voltmeter is not pulsating but reads within one volt of battery voltage, go to next step. If voltmeter is not pulsating but reads 0-1 volt, go to step 3). (Scheme 300): Canister Purge Solenoid Circuit (All Others, 1 of 3)
2. Turn ignition switch off. Disconnect computer 14-way connector. Connect voltmeter to cavity No. 8 of 14-way connector and ground. Turn ignition switch to "RUN" position. If voltmeter is within one volt of battery voltage repair wire of cavity No. 8 for an open circuit to canister purge control solenoid. (Scheme 301): Canister Purge Solenoid Circuit (All Others, 2 of 3)
3. Turn ignition switch off. Disconnect computer 14-way connector. Turn ignition switch to "RUN" position. If voltmeter is within one volt of battery voltage, computer should be replaced. If voltmeter is not within one volt of battery voltage, repair canister purge solenoid control wire (Green/Yellow), for short to ground.

Canister Purge Solenoid Circuit (All Others, 3 of 3). Scheme 302

Scheme 303

1. Turn ignition switch off. Move read/hold switch on diagnostic readout box to "hold"position. Start engine and raise RPM to 2000. If display on readout box switches between a dash and blank, oxygen feedback system is not cause of problem. Perform «DR21»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec). If display on diagnostic readout box is blank, go to next step.
2. Return engine to idle. Disconnect oxygen sensor. Connect one end of jumper wire to harness end of O2 sensor connector. Touch other end of jumper wire to battery positive post. If readout box shows a dash, go to next step. If readout box is blank, go to step 4). (Scheme 303): Oxygen Feedback System Locked on Lean Rail (1 of 2)
3. Turn engine off. Put system in "Test Mode 91." If O2 sensor on carburetor is clicking, replace oxygen sensor. If O2 solenoid is not clicking O2 solenoid should be replaced.
4. Be sure O2 sensor connector is disconnected. Turn engine off, disconnect 14-way connector. Connect ohmmeter between oxygen sensor harness connector and cavity No. 10 of 14-way connector. If ohmmeter reading shows continuity and computer terminals are okay, computer should be replaced. If ohmmeter reading does not show continuity, repair wire for an open circuit to computer.

Oxygen Feedback System Locked on Lean Rail (2 of 2). Scheme 304

Scheme 305

1. Be sure diagnostic readout box is connected to engine harness connector. Turn ignition off. Move read/hold switch on readout box to "hold"position. Start engine and raise RPM to 2000. If display on readout box is switching between a dash and blank, oxygen feedback system is not cause of rich condition. Go to DR21. If display shows a dash, go to next step.
2. Return engine to idle. Disconnect oxygen sensor connector. If display on readout box is blank, go to next step. If readout box displays a dash, computer should be replaced. (Scheme 305): Oxygen Feedback System Locked on Rich Rail
3. Turn engine off. Pub system in "Test Mode 91". If O2 solenoid on carburetor is clicking, oxygen feedback system a not cause of rich condition. Perform «DR21»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec). If O2, solenoid on carburetor is not clicking, replace O2 solenoid.

Scheme 306

Scheme 307

1. Disconnect coolant sensor harness connector. Put system into "Test Mode 92". Readout box display should be.01". If display reads "01", proceed to step 2). If display does not read "01", replace computer.
2. Connect a jumper lead between terminals No. "1" and "3" of coolant sensor harness connector. Readout box display should change to "03" when jumper lead is connected. If display changes, proceed to step 3). If display does not change, proceed to step 5. (Scheme 306): Coolant Sensor Circuit Test (1 of 3)
3. Put system into "Test Mode 92". Readout box display should change to ".03". If display changes to "03", proceed to step 4). If readout box display does not change, replace computer.
4. Connect jumper lead between terminals No. "1" and "2" of coolant sensor harness connector. If readout box display does not change, repair open circuit between coolant sensor connector terminal No. "2" and computer 14-way connector cavity No. "9". (Scheme 307): Coolant Sensor Circuit Test (2 of 3)
5. Connect a jumper lead between coolant sensor harness connector terminal No. "3" and an engine ground. Readout box display should change from "01" to "03". If display changes, repair wire from terminal coolant sensor connector terminal No. "1" and ground for an open circuit. If display does not change repair open circuit between coolant sensor connector terminal No. "3" and computer 14-way connector cavity No. "9".

Coolant Sensor Circuit Test (3 of 3). Scheme 308

Scheme 309

Scheme 310

Scheme 311

1. Disconnect speed sensor connector. Put system into "Test Mode 96" readout box display should be "02". If readout box display reads "02', proceed to step 2). If display is not "02", replace computer. (Scheme 309): Speed Sensor System Test (1 of 4)
2. Connect a jumper lead between terminals of speed sensor connectors on engine harness. Readout box display should change from "02" to "01". If display changes from "02" to "-1", proceed to step 3) If display changes from "02" to "01", proceed to step 3), if display should not change, proceed to step 6. (Scheme 310): Speed Sensor System Test (2 of 4)
3. Turn ignition off. Remove speed sensor from transaxle. Connect ohmmeter between speed sensor connector terminate. Slowly rotate speed sensor one turn. Ohmmeter should show 8 pulses for every turn of speed sensor. If ohmmeter readings if okay, inspect transaxle drive gear and speed sensor drive gear for proper contact. If ohmmeter reading is not okay, replace speed sensor. (Scheme 311): Speed Sensor System Test (3 of 4)
4. Connect a jumper lead to White/Orange wire of speed sensor harness connector and ground. Readout box display should change from "O2" to "O1". If display changes, repair Black/Blue wire of speed sensor harness connector for an open circuit. If display does not change, repair White/Orange wire of speed sensor connector for an open circuit.

Speed Sensor System Test (1 of 4). Scheme 312

Scheme 313

Scheme 314

Scheme 315

1. Disconnect diagnostic readout box from engine harness diagnostic connector. Ensure diagnostic readout box is operational. Connect a voltmeter to engine harness diagnostic connector cavity No. "4" and ground. Turn ignition switch to "RUN" position. Voltmeter reading should be 4-5 volts. (Scheme 313): Checking for NO Code 88 (1 of 3)
2. If voltage is okay, turn ignition off.Disconnect computer 14-way connector. Connect an ohmmeter between engine harness diagnostic connector cavity No. "2" and computer 14-way connector cavity No. "14". Ohmmeter should show continuity. (Scheme 314): Checking for NO Code 88 (2 of 3)
3. If there is continuity, ensure terminal in computer connector cavity No. "14" is not spread apart causing a poor connection. If connection is okay, replace computer. If there is no continuity, repair wire to connector cavity No. "14" for an open circuit to engine harness connector.
4. If voltage reading in step 1) was not within specifications, turn ignition off. Disconnect computer 14-way connector. Connect an ohmmeter between engine harness diagnostic connector cavity No. "4" and computer 14-way connector cavity No. "1". Ohmmeter should show continuity. (Scheme 315): Checking for NO Code 88 (3 of 3)
5. If there is continuity, ensure terminal in computer connector cavity No. "1" is not spread apart causing a poor connection. If connection is okay, replace computer. If there is no continuity, repair wire to connector cavity No. "1" for an open circuit to engine harness connector.

DR13 - CARBURETOR CHOKE SYSTEM TEST

1. Set accelerator linkage to proper start position. Remove air cleaner. Check choke plate and fast idle cam position.
2. Choke plate should be in fully closed position and fast idle screw should be on highest step of fast idle cam. If choke and cam position are okay, proceed to DR14. If choke is not fully closed or cam is not in position, check choke plate for sticking or binding. Repair choke and linkage as required.

DR14 - CHECKING CHOKE VACUUM KICK

1. Remove air cleaner. Set fast idle speed screw on highest step of fast idle cam. Remove vacuum hose from choke diaphragm. Connect a vacuum pump to choke diaphragm and apply 15 in. Hg of vacuum. Measure clearance between top of choke plate and air horn wall.
2. Vacuum should hold at applied setting and choke plate should be in proper position of vacuum kick specifications. If vacuum holds and choke vacuum kick is within specifications, proceed to «DR15»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr15-heated-air-intake-system) . If vacuum does not hold, replace choke vacuum kick diaphragm. Adjust choke vacuum kick as necessary.

DR15 - HEATED AIR INTAKE SYSTEM CHECK

1. Disconnect air duct from air cleaner snorkel. Disconnect vacuum hose to heated air intake system air temperature sensor. Connect a vacuum pump to sensor and apply 15 in. Hg of vacuum. Vacuum should close heated air close heated air door when air temperature is below 76°F (25°C) and then slowly bleed down, opening heated air door.
2. If vacuum builds up, closes heated air door and then bleeds down, proceed to DR16. If vacuum builds up but heated air door does not close, repair or replace door as necessary. If vacuum does not build up or does not bleed down, replace air temperature sensor. If vacuum builds up and bleeds down, but heated air door does not open, repair or replace door as required.

DR16 - ENGINE COOLING FAN CALIBRATION CHECK

1. Connect diagnostic readout box to engine harness connector. Put system into Test Mode 92. Readout box display should read as shown in «COOLANT SENSOR CALIBRATION»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) chart. If display code is okay, proceed to step 2). If display code is not okay, replace coolant sensor. COOLANT SENSOR CALIBRATION (1) Coolant Temperature Display Less Than 50°F (10°C) 01 50 - 100°F (10 -38°C) 02 More Than 100°F (38°C) 03 (1) System in Test Mode 92.
2. Put system into Test Mode 93. Display should read as shown in «FAN COOLANT SENSOR CALIBRATION»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) chart. If display code is okay, proceed to DR17. If display code is not okay, replace coolant sensor.

FAN COOLANT SENSOR CALIBRATION (1)

DR17 - EGR SYSTEM CVSCC VALVE TEST

Disconnect EVSCC valve at vacuum hose connector. Connect vacuum pump to valve and apply at least 10 in. Hg vacuum. Vacuum should hold with coolant temperature below 125°F (52°C). If vacuum does not hold, replace CVSCC valve.

Scheme 316

1. Remove air cleaner. Start engine. Check position of choke plate. Choke plate should open from a fully closed position. If choke plate is in proper position, proceed to step 2). If not, proceed to step 5).
2. Connect a voltmeter between choke connector and ground. Voltage reading should be within one volt of battery voltage. If voltage reading is okay, proceed to «DR19»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr19-checking-for-fuel-fouled). If voltage is not okay, turn ignition off. Connect a voltmeter to oil pressure switch harness connector terminal "C" and ground.
3. Turn ignition switch to "RUM" position. Voltage should be within one volt of battery voltage. If voltage reading is okay, proceed to step 4). If voltage reading is not okay, check harness to ignition switch for an open circuit.
4. Turn ignition off. Connect an ohmmeter to oil pressure switch connector terminal "A" and choke connector. Ohmmeter should show continuity with no resistance. If there is continuity, replace oil pressure switch. If there is no continuity, repair harness for an open circuit. (Scheme 316): Choke Position Check (3 of 1)
5. Disconnect vacuum hose from choke vacuum kick diaphragm. Connect a vacuum gauge to hose. Start engine. Vacuum gauge reading should be manifold vacuum. If vacuum reading is okay, repair choke linkage. If vacuum reading is not okay, repair vacuum source from carburetor.

Note. There is a 10 second delay valve installed in this hose.

Choke Position Check (4 of 1). Scheme 317

DR19 - CHECKING FOR FUEL FOULED SPARK PLUGS

Remove spark plugs, spark plugs should be dry. If spark plugs are okay, proceed to DR20 . If spark plugs are wet with fuel, clean and reinstall. Check for gas in crankcase. Change oil and filter as necessary.

Scheme 318

1. Remove bowl vent hose from carburetor and canister. Blow lightly into the hose. Air should flow through the hose. If air does not flow through hose, clear hose or replace bowl vent valve. Look for liquid in hose near canister. If liquid is found in hose, check hose routing.
2. If air flows through the hose, remove the air pressure hose from bowl vent valve. Connect the pressure side of an auxiliary vacuum supply pump to the air pressure connector of the bowl vent valve. Blow lightly into hose on the canister side of the bowl vent valve. Apply pressure. DO NOT apply more than 20 psi. (Scheme 318): Bowl Vent Valve
3. Air should flow through hose, and as pressure is applied, the sound of the air flowing through the hose should change. If air flows through the hose and the sound changes as pressure is applied, check for air pressure in hose from the air switch relief valve. If okay, proceed to DR26. If air does not flow through hose or the sound of air flowing does not change, replace the bowl vent valve.

Scheme 319

1. Disconnect computer 10-way connector. Connect ohmmeter between cavity "7" of 10-way connector and ground. Open and close throttle while watching the ohmmeter. Ohmmeter should show continuity with no resistance when throttle is closed and no continuity when throttle is open. If okay, proceed to «DR19»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr19-checking-for-fuel-fouled). (Scheme 319): Computer 10-Way Connector
2. If no continuity is present with throttle closed, repair the wire from cavity "7" to the carburetor switch for open circuit. If there is continuity with resistance when throttle is closed, clean corrosion from carburetor switch. If there is continuity with throttle open, repair the wire from cavity "7" for a short to ground.

DR22 - ENGINE COOLANT SENSOR CALIBRATION CHECK

1. Connect diagnostic read-out box to the engine harness connector. Put the system into Sensor Test Mode 92. Read-out box display should read as shown in «COOLANT SENSOR CALIBRATION»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) chart. If display code is okay, proceed to step 2). If display code is not okay, replace the coolant sensor.
2. Put the system into Sensor Test Mode 93. Display should read as shown in «FAN COOLANT SENSOR CALIBRATION»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) chart. If display code is okay, proceed to «DR14»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr14-checking-choke-vacuum-kick) . If display code is not okay, replace coolant sensor.

Scheme 320

Scheme 321

1. Remove air cleaner and start engine. Choke should be fully open. If choke position is okay, proceed to «DR21»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec). If choke position is not okay, with engine running, connect voltmeter to choke connector and ground. Voltmeter should read within one volt of battery voltage. If voltage is okay, check for binding linkage. If okay, replace choke thermostat housing. If voltage is not okay, proceed to step 2). (Scheme 320): Choke Connector
2. Turn ignition off. Disconnect oil pressure switch connector. Connect voltmeter to terminal "C" of the oil pressure switch connector and ground. Turn ignition switch to "RUN" position. Voltage should be within one volt of battery voltage. If voltage is okay, proceed to step 3). If voltage is not okay, repair open circuit in harness to ignition switch. (Scheme 321): Oil Pressure Switch Harness Connector
3. Turn the ignition off. Connect ohmmeter between terminal "A" of connector and choke connector. Ohmmeter should show continuity with no resistance. If there is continuity, replace oil pressure switch. If there is no continuity, repair open circuit in harness.

Oil Pressure Switch Harness Connector. Scheme 322

Scheme 323

1. Connect tachometer to engine. Remove air cleaner. If equipped, disconnect and plug vacuum hose at solenoid kicker. Start engine, momentarily raise engine speed above 1100 RPM and then wait 2 minutes for idle speed to stabilize. Plug idle air bleed hole. (Scheme 323): Carburetor Idle Circuit
2. Engine speed should drop. If engine speed drops, proceed to DR22. If engine speed does not drop, or if engine speed increases, repair carburetor for plugged idle circuit.

DR25 - EGR SYSTEM TEST

1. Connect tachometer to engine. Disconnect vacuum hose from the EGR valve. Connect a vacuum pump to the EGR valve. If equipped, disconnect and plug vacuum hose at solenoid kicker. Start engine, momentarily raise engine speed above 1100 RPM and wait 2 minutes for idle speed to stabilize. Very slowly apply vacuum to EGR valve.
2. Engine speed should begin to drop when applied vacuum reaches 2-5 in. Hg vacuum and continue to drop as more vacuum is applied. Engine may stall before 5 in. Hg vacuum is applied. If engine speed drop is okay, proceed to step 3). If engine speed does not drop or engine speed does not drop until 5 in. Hg or more vacuum, replace EGR valve.
3. Connect vacuum gauge to EGR vacuum hose. Slowly increase engine speed. As engine speed increases, so should reading on vacuum gauge. If vacuum reading is okay, check the EGR tube attaching nut on the bottom side of the intake manifold for a vacuum leak. If no leak, proceed to DR23. If vacuum reading is not okay, proceed to step 4).
4. Turn engine off. Remove connector from EGR CVSCC valve. Connect vacuum pump to either port of valve. Try to apply vacuum. Vacuum should not hold with coolant temperature above 125°F (52°C). If vacuum does not hold, check EGR signal hose from carburetor for leaks or restrictions. If vacuum holds, replace EGR CVSCC valve.

DR26 - AIR SWITCHING SYSTEM TEST

1. Remove air cleaner. Disconnect downstream air hose from switch/relief valve. Start the engine. With engine coolant above 150°F (67°C), air should be flowing from downstream air port of switch/relief valve.
2. If air is flowing from downstream port, proceed to DR24. If air is not flowing from downstream air port, disconnect vacuum hose from air switch/relief valve. Connect a vacuum gauge to hose. There should be no vacuum. If there is no vacuum, replace the air switch/relief valve. Ensure the vacuum bleed is able to release vacuum from this hose when the CVSCO valve shuts off the vacuum source. If vacuum is present, replace CVSCC valve.

DR27 - SOLENOID KICKER CHECK

1. Remove air cleaner cover. Have an assistant turn ignition switch to the "RUN" position while you watch the solenoid plunger. Slowly open throttle. Plunger should move out when key is turned on or when throttle is opened. If plunger movement is okay, proceed to step 3).
2. If plunger movement is not okay, check solenoid adjusting screw to be sure that it is not turned in all the way (preventing plunger movement). If not, replace solenoid kicker.
3. With ignition switch in the "RUN" position, disconnect vacuum hose from solenoid kicker. Connect a vacuum pump to the solenoid kicker and apply 15 in. Hg vacuum. Release vacuum. Plunger should move out when vacuum is applied and return when vacuum is released. If plunger movement is okay, proceed to «DR25»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr25-egr-system-test) . If movement is not okay, replace solenoid kicker.

DR28 - CARBURETOR BOWL VENT SYSTEM CHECK

1. Remove bowl vent hose from carburetor and canister. Blow lightly into the hose. Air should flow through the hose. If air does not flow through the hose, clear hose or replace bowl vent valve. Look for liquid in hose near canister. If liquid is found in hose, check hose routing.
2. If air flows through the hose, remove the air pressure hose from bowl vent valves. Connect the pressure side of an auxiliary vacuum supply pump to the air pressure connector of the bowl vent valve. Blow lightly into hose on the canister side of the bowl vent valve. Apply pressure. DO NOT apply more than 20 psi.

Bowl Vent Valve. Scheme 324

DR29 - HEATED AIR INTAKE SYSTEM CHECK

1. Disconnect the air duct from the air cleaner snorkel. Disconnect the vacuum supply hose to the heated air intake air temperature sensor. Connect a vacuum pump to the sensor. Try to apply vacuum. Vacuum should not hold and heated air door should be open.
2. If vacuum does not hold and heated air door is open, proceed to «DR27»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr27-solenoid-kicker-check) . If vacuum holds, replace the air temperature sensor. If heated air door is not open, repair or replace as necessary.

DR30 - VACUUM TRANSDUCER CALIBRATION CHECK

1. Connect the diagnostic read-out box to the engine harness connector. Put the system into "Sensor Test Mode 91". Connect a vacuum pump to the vacuum transducer. Diagnostic read-out box display should be as shown in «VACUUM TRANSDUCER CALIBRATION»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) chart when vacuum is applied to the computer. VACUUM TRANSDUCER CALIBRATION Vacuum (In. Hg) Read-Out Box Display 0-5 01 5-15 02 More Than 15 03
2. If diagnostic read-out box displays correspond to vacuum readings, proceed to «DR28»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr28-carburetor-bowl-vent-system) . If display codes are not correct, replace the computer.

Scheme 325

1. Remove air cleaner cover. Watch plunger of solenoid kicker diaphragm while an assistant starts the engine. Vacuum diaphragm plunger should move out and hold throttle open for at least 5 minutes and then return throttle to curb idle position. NOTE: Some systems may hold throttle open for less than 5 minutes.
2. If plunger movement is okay, proceed to step 3), if equipped with A/C. If not A/C equipped, proceed to DR29. If there is no plunger movement, proceed to step 6).
3. Press A/C button and watch the solenoid kicker vacuum diaphragm plunger. Vacuum diaphragm plunger should move out and hold throttle open while A/C compressor clutch is engaged. If plunger movement is okay, proceed to «DR29»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr29-heated-air-intake-system). If no plunger movement, proceed to step 4).
4. Connect diagnostic read-out box to engine harness connector. Put system in "Switch Test Mode". Ensure A/C control is in "OFF" position. Press A/C button on and off. Code 88 should appear on display when A/C button is pressed on and then return to 00 when turned off. If Code 88 appears when A/C button is turned on, replace computer. If Code 88 does not appear, proceed to step 5).
5. Turn the ignition off. Disconnect computer 14-way connector. Connect voltmeter to cavity "7" of 14-way connector and ground. Ensure A/C button is off. Turn ignition switch to "RUN" position. Voltmeter should read within one volt of battery voltage. If voltage is okay, replace computer. If voltage is not okay, inspect wire from cavity "7" to A/C push button switch for an open circuit and repair as needed. (Scheme 325): Computer 14-Way Connector
6. Turn engine off. Disconnect vacuum supply hose from solenoid kicker and connect a vacuum gauge to it. Start engine. Vacuum gauge reading should be intake manifold vacuum. If vacuum is okay, replace the solenoid kicker. If there is no vacuum, repair vacuum supply from carburetor.

DR32 - IGNITION SYSTEM CHECK

Connect engine analyzer to engine. Start engine and let engine speed stabilize for 2 minutes. Follow equipment manufacturer's procedure for secondary ignition testing and pattern analysis. Check the ignition coil open circuit output. Open circuit output should be at least 25,000 volts. If secondary ignition system is okay, proceed to DR30 . If secondary ignition is not to specifications, repair as required.

DR33 - BASIC IGNITION TIMING CHECK

1. Connect a tachometer and timing light to engine. Ground carburetor switch. Start engine and run until normal operating temperature is reached. Momentarily raise engine speed above 1100 RPM. Disconnect and plug vacuum hose at solenoid kicker. Disconnect and plug vacuum hose at computer (engine RPM will drop when line is disconnected).
2. Engine idle speed should be below curb idle specifications. If necessary, turn idle screw to lower engine RPM. Basic timing should be within 2° of specifications shown on emissions label. If basic timing is okay, proceed to step 3). If timing not, adjust as necessary.
3. With engine running at operating temperature, remove jumper wire from carburetor ground switch. Connect vacuum pump to computer and apply 16 in. Hg vacuum. Raise engine speed to 2000 RPM. Timing should be within 4° of specification. If spark is okay, proceed to step 4). If spark advance is not okay, replace computer.
4. With engine running at normal operating temperature, return engine to idle speed. Unplug hose to computer and connect vacuum gauge. Gauge should read manifold vacuum. If vacuum is okay, proceed to «DR31»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec) . If vacuum is not okay, check vacuum supply from carburetor.

DR34 - ENGINE IDLE SYSTEM CHECK

1. Turn off all lights and accessories. Connect tachometer to engine. Jumper the radiator cooling fan connector so that the fan will run continuously. Remove PCV valve and allow it to draw outside air. Disconnect and plug vacuum hose at the solenoid kicker.
2. Start engine and momentarily raise engine speed above 1100 RPM. Wait 2 minutes for engine speed to stabilize. Tachometer should indicate same RPM as shown on emission label. If idle speed is okay, proceed to step 3). If idle speed is not okay, turn idle speed screw until engine RPM is the same as shown on emission label and proceed to step 3).
3. Remove hose to heated air sensor from 3-way connector and install propane supply hose in its place. Open propane main valve. Meter propane until maximum RPM is reached. Engine speed should increase by 50 RPM F40 RPM. If engine speed is okay, proceed to step 4). If engine speed increase is not okay, adjust according to propane assisted idle set procedure.
4. With engine running at normal operating temperature, turn propane valve off. Remove propane bottle. Open throttle and set fast idle adjustment screw on slowest speed step of fast idle cam. Fast idle speed should be within specifications shown on emission label F100 RPM. If idle speed is okay, proceed to step 5). If fast idle speed is not okay, adjust to specifications.
5. With engine running at normal operating temperature, reinstall PCV valve. Remove jumper wire from radiator fan and reconnect connector. Remove power feed wire to S.I.S. or solenoid kicker from carburetor 6-way connector. Tachometer should read 600 RPM or less. If engine speed is okay, proceed to «DR32»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#22l-electronic-fuel-control-cec__dr32-ignition-system-check) . If speed is greater than 600 RPM, adjust to specifications.

DR35 - SYSTEM & COMPONENT CHECKS

At this point, test procedures have determined that all engine control systems are operating correctly and are not the cause of the driveability problem. Check the following as possible causes

1. Check for at least 13 in. Hg engine vacuum in Neutral.
2. Check engine valve timing.
3. Check engine compression.
4. Check engine cooling system.
5. Check exhaust system for restrictions.
6. Check engine PCV system for free flow.
7. Check fuel pump pressure, volume and vacuum.
8. Check torque converter stall speed.
9. Check power brake booster for internal vacuum leaks.
10. Check for fuel contamination.
11. Check carburetor for circuit contamination and proper calibration.
12. Check Technical Service Bulletins that may apply to vehicle.

2.2L FWD EFC System Wiring Diagram. Scheme 326

Dakota RWD 2.2L EFC System Wiring Diagram. Scheme 327

See also:
• SPARK ADVANCE TEST SPECIFICATIONS
• NS2
• NS5
• NS3
• NS7
• NS4
• NS6
• DR15
• DR19
• DR14
• DR25
• DR27
• DR28
• DR29
• DR30
• DR32