2.5l Efc System Dodge Caravan I

DESCRIPTION

The Electronic Fuel Control system is a computer regulated fuel delivery system that provides precise air/fuel mixture during all engine operating conditions. The control unit is a Single Module Engine Controller (SMEC), that regulates ignition timing, air/fuel mixture, emission control devices, cooling fan, charging system and idle speed.

TROUBLE CODE-TO-TEST MENU

TROUBLE CODE-TO-TEST MENU

OPERATION

Fuel flow operation from the Single-Point injection system is controlled by SMEC. SMEC receives inputs from various sensors in order to correctly regulate fuel flow at the injector. These include the Manifold Absolute Pressure (MAP) sensor, Throttle Position Sensor (TPS), Oxygen (O2) sensor, coolant temperature sensor, throttle body temperature sensor and vehicle distance sensor. All inputs are converted into signals that are used to adjust air/fuel mixture and/or ignition timing.

A/C CUT-OUT RELAY

The A/C cut-out relay is connected in series with the A/C damped pressure switch, A/C switch and A/C fan relay. The relay remains in the energized ("ON") position during engine operation. When SMEC senses low idle speeds or wide open throttle position (through TPS), it de-energizes the relay and causes the compressor clutch to disengage.

AUTOMATIC IDLE SPEED (AIS) MOTOR

The AIS motor is operated by the Single Module Engine Controller (SMEC). The SMEC uses input information from the various sensors to determine idle speed. The AIS motor meters a portion of the air/fuel mixture through an air by-pass in the throttle body. An increase or decrease in the amount of air/fuel mixture through the air by-pass is used to control idle speed.

AUTO SHUTDOWN (ASD) RELAY

The ASD interrupts power to the electric fuel pump, fuel injectors and ignition coil, when the ignition switch is in "RUN" position and no distributor signal is present.

CHECK ENGINE LIGHT

The check engine light illuminates each time the ignition is turned on, and stays on for 3 seconds as a bulb test. If SMEC receives an incorrect signal or no signal from certain sensors, the check engine light will be illuminated. This an indication that the SMEC has entered into an limp-in mode. This limp-in mode is an attempt to keep the system operating despite system fault.

COOLANT TEMPERATURE SENSOR

The coolant temperature sensor monitors engine operating temperature. The sensor is mounted in the thermostat housing. The coolant sensor provides data to SMEC on the engine operating temperature. SMEC uses this information to assist in determining proper air/fuel mixture at various temperatures. The sensor is also used to operate the electric cooling fan.

FUEL INJECTOR

The fuel injector is an electrically actuated solenoid that is driven or energized by SMEC. Fuel delivery is controlled by the length of time that the injector is energized. SMEC uses input signals from the various sensors to determine how long to energize the injector. Fuel is supplied to the injector at a constant pressure of 14.5 psi (1.02 kg/cm 2 ).

FUEL PRESSURE REGULATOR

The fuel pressure regulator is a mechanical device that maintains a constant pressure of 14.5 psi (1.02 kg/cm 2 ) across the injector tip. When fuel pressure reaches the given amount, fuel is allowed to enter the return port and is returned to the fuel tank. The internal diaphragm and spring constantly move from an open to closed position in order keep fuel pressure constant.

HEATED OXYGEN (O2) SENSOR

The O2 sensor produces an electrical voltage in response to the amount of oxygen in the exhaust gases. The O2 sensor is mounted in the exhaust manifold and is electrically heated internally for faster switching from open loop to closed loop operation. By monitoring the amount of oxygen in the exhaust gases, the O2 sensor acts as an rich/lean switch. This is accomplished through SMEC, which reads the voltage signal from the O2 sensor and adjusts injector pulse width (on time) to maintain proper air/fuel ratio.

MANIFOLD ABSOLUTE PRESSURE (MAP)

The MAP sensor is a device that monitors manifold vacuum. The MAP sensor is connected to a vacuum nipple on the throttle body and electrically sends signals to SMEC. SMEC uses this data to determine engine load. This information is used with other data to determine the proper air/fuel mixture.

PURGE SOLENOID

The purge solenoid is controlled by SMEC. When engine operating temperature is below 45°F (61°C), SMEC grounds the purge solenoid thereby energizing the component. This prevents vacuum from reaching the charcoal canister valve. When temperature reaches or exceeds the given value, the purge solenoid is de-energized and vacuum is allowed to flow to charcoal canister valve. Normal purging of fuel vapors to throttle body is then allowed to continue.

SINGLE MODULE ENGINE CONTROLLER (SMEC)

The SMEC is a digital computer containing a microprocessor. The module receives input signals from various switches and sensors. After computing input data, SMEC sends output signals to the fuel injectors, distributor, ignition coil, AIS motor, purge solenoid, alternator and cooling fan switch.

The SMEC contains the circuits necessary to drive the ignition coil, fuel injector and alternator field. These are high current devices and have been isolated to minimize electrical noise in the passenger compartment. Distributor pick-up signal goes to the SMEC. If no distributor signal is given to SMEC, power is shut off from the fuel injector, fuel pump and ignition coil.

The SMEC also performs self diagnostic functions. This diagnostic information is stored as trouble codes. Trouble codes can be read by an technician by means of an diagnostic readout tool, or by means of the instrument panel check engine light.

SWITCH INPUT

Various switches provide information to SMEC. These include the neutral safety switch, A/C clutch switch, speed control switch and brake light switch. If one or more of these switches is sensed as being in the "ON" position, SMEC will signal the AIS motor to regulate idle speed at a scheduled RPM.

THROTTLE BODY

The throttle body assembly is mounted on the intake manifold and houses the fuel injector, fuel pressure regulator, TPS, AIS motor and throttle body temperature sensor. The throttle body meters air/fuel mixture delivery to intake ports. The throttle body also serves as a chamber for atomization of incoming air and fuel.

THROTTLE BODY TEMPERATURE SENSOR

The throttle body temperature sensor is used to determine fuel temperature. This sensor inputs necessary information needed by SMEC to provide proper air/fuel mixture during hot restart conditions.

THROTTLE POSITION SENSOR (TPS)

The TPS is mounted on the throttle body and senses the angle of the throttle body valve (butterfly). This information is used by the SMEC in determining the proper air/fuel mixture during varying driving conditions such as acceleration, deceleration, idle and wide open throttle.

PRELIMINARY CHECKS

Most driveability problems in the engine control system result from faulty or poor wiring, or loose and/or leaking hose connections. To avoid unnecessary component testing, a visual check should be performed before beginning troubleshooting procedures to help spot these common faults. A preliminary visual check should include the following

1. Verify that battery terminals are clean and that battery is fully charged.
2. Verify that vacuum connections on rear of throttle body are secure and not leaking.
3. Check that all vacuum connections to purge solenoid are secure and not leaking.
4. Check hoses to vapor canister.
5. Verify that PCV valve is securely attached to intake manifold vacuum port and orifice plug is in valve cover nipple.
6. Check that alternator wiring and belt are secure.
7. Check vacuum line to MAP sensor.
8. Check fuel lines to fuel pump. Verify that wiring is secure and not damaged.
9. Verify that heated air door vacuum connections are secure and not leaking.
10. Check hoses to back pressure transducer.
11. Check power brake and speed control vacuum hoses.
12. Verify that all connectors to SMEC are fully inserted into sockets. Check all other connectors to various sensors and switches.

ON-BOARD DIAGNOSTIC SYSTEM DESCRIPTION

All 1987 Caravan and Voyager vans equipped with 2.5L engines and electronic fuel injection have an On-Board diagnostic system. This system allows faster diagnostic times in determining where the problem is. The engine control module monitors critical input and output circuits that are related to engine functions. If the on-board diagnostic system senses that one of the circuits is bad during a predetermined amount of time, the monitoring cycle will consider this a real problem and set a fault code.

ENTERING ON-BOARD DIAGNOSIS

1. Connect diagnostic tool to mating connector located in wiring harness by left front shock tower.
2. Place read/hold switch on readout box in "READ" position. Turn ignition on, off, on, off, on within 5 seconds.
3. Record all codes displayed. It is possible to stop displaying codes by moving read/hold switch to "HOLD" position. Returning to "READ" position will continue displaying codes.

FAULT CODES

Fault codes (or trouble codes) are 2 digit numbers that identify which circuit is bad. In most cases the fault codes do not identify which component is bad. Therefore, a fault code is only the result, not the reason for the problem. There are some cases in which the fault code is the reason for the problem. It is important that the test procedure be followed in order to fully understand the possible cause of the fault code.

The Chrysler throttle body fuel injection system is equipped with on-board diagnostic capabilities which store certain trouble codes in the logic module when a system malfunction occurs. These codes may be recalled to aid in system diagnosis. The following list presents these codes and the system malfunctions which they represent.

Code 88

This code implies the start of diagnostic mode. If this code is not displayed first, trouble codes will be inaccurate.

Code 11

Problem with distributor circuit. Appears as if there has been no distributor signal to the logic module since restoration of battery voltage.

Code 13

Problem with MAP sensor pneumatic system. Appears as if sensor vacuum level does not change between cranking and when engine starts. Engine Running Test Mode 68.

Code 14

Problem with MAP sensor electrical system. MAP sensor signal voltage outside of .02-4.9 volt range. Sensor Test Mode 08.

Code 15

Problem with Distance/Speed Sensor circuit. During 7-second period of deceleration from highway speeds with throttle closed, sensor indicates less than 2 MPH when vehicle is moving. Engine Running Test Mode 71.

Code 16

Problem with loss of battery sensing voltage. Occurs if sensing voltage drops below 4 volts or between 7.5-8.0 volts for more than 20 seconds. Sensor Test Mode 07. Engine Running Test Mode 67.

Code 17

Problem with engine cooling system. Occurs if engine coolant temperature does not reach 160°F (71°C) within 8 minutes after vehicle speed reaches 28 MPH.

Code 21

Problem with O2 sensor feedback circuit. Occurs if engine is in closed loop, but O2 sensor stays rich or lean (no signal) for more than 22 seconds. Engine temperature should be above 170°F (77°C) and engine speed should be above 2000 RPM. Sensor Test Mode 02. Engine Running Test Mode 62.

Code 22

Problem with coolant temperature sensor circuit. Appears as the coolant sensor voltage is below .51 volt when engine is warm or above 4.96 volts when engine is cold. Sensor Test Mode 04. Engine Running Test Mode 64.

Code 23

Problem with throttle body temperature sensor circuit. Appears if the throttle body temperature sensor voltage is below .04 volt or above 4.98 volts when engine coolant temperature is above 77°F (25°C). Sensor Test Mode 03. Engine Running Test Mode 63.

Code 24

Problem TPS circuit. Appears if the sensor signal is either below .16 volt or above 4.7 volts. Sensor Test Mode 05. Engine Running Test Modes 65 and 69.

Code 25

Problem with AIS motor control circuit. Appears if proper voltage from AIS system is not present. An open harness or motor will not activate this code. ATM code 03.

Code 26

Problem with fuel injector driver. Indicates that peak injector driver current level has not been reached during cranking. ATM code 02.

Code 27

Problem with fuel control circuit in logic module. Appears when fuel control interface fails to switch properly.

Code 31

Problem with canister purge solenoid circuit. Appears if solenoid does not turn on and off when it should. ATM code 07.

Code 33

Problem with A/C cut-out relay driver circuit. Occurs when relay does not turn on and off when it should. ATM code 05.

Code 34

Problem with cruise control servo circuit. Occurs if servo does not turn on and off when it should. ATM code 08.

Code 35

Problem in the radiator fan relay circuit. Appears if relay does not turn on and off when it should. ATM code 04.

Code 41

Problem with charging system. Occurs if field control fails to switch properly. ATM code 09.

Code 42

Problem in the ASD relay circuit. Occurs if control voltage of the relay pull-in coil in the power module is not correct. Occurs if relay does not turn on and off when it should.

Code 43

Problem in the spark control interface circuit. Occurs if spark control interface fails to switch properly. ATM code 01.

Code 44

Occurs if fused J2 is not present in the logic board of the engine control module.

Code 46

Problem with battery temperature sensing voltage. Sensing voltage is too high. Appears if battery sensing voltage is less than one volt below the desired control voltage for more than 20 seconds. Sensor Test Mode 07. Engine Running Test Mode 67.

Code 47

Problem is battery sensing voltage is too low. Appears if battery sensing voltage is less than one volt below the desired control voltage for more than 20 seconds. Occurs with engine temperature above 160°F (71°C) and speed above 1500 RPM. Sensor Test Mode 07. Engine Running Test Mode 67.

Code 51

Problem with oxygen feedback system. Occurs if O2 sensor indicates a lean condition for more than 12 minutes. Engine Running Test Mode 0-1 switching.

Code 52

Problem with oxygen feedback system. Occurs if O2 sensor indicates a rich condition for more than 12 minutes. Engine Running Test Mode 0-1 switching.

Code 53

Problem with an internal logic module failure. Occurs if logic module fails.

Code 55

Indicates end of diagnostic mode.

Scheme 59

Scheme 60

1. Unplug any spark plug wire and insert screwdriver in terminal. Hold screwdriver shaft (1/4") from good engine ground. Crank engine and check for good spark as long as engine is cranking. If spark is okay, go to «NS2 - CHECKING FOR FUEL SPRAY»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system__ns2-checking-for-fuel-spray). If spark is not okay (no spark) or intermittent, go to next step. (Scheme 59): Screwdriver & Spark Plug Wire (Scheme 60): Ignition Coil Wire
2. Unplug ignition coil wire from distributor cap. Hold coil wire 1/4" near good engine ground and crank engine. Check for good spark between coil wire and ground. If spark is good, repair secondary ignition system (distributor cap and/or rotor). If spark is not good, check ignition coil wire. If coil wire is okay, go to step 3). CAUTION: DO NOT hold coil wire more than 1/4" from ground. If this occurs fault code erasure and engine control module damage may result.
3. Remove air cleaner cover. Connect ignition coil wire to distributor cap. Crank engine and check for fuel spray from injector. If there is fuel spray, go to «NS6 - CHECKING FOR CODE 43»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system__ns6-checking-for-code-43). If no fuel spray, go to «NS14 - CODES 11»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system__ns14-codes-11-12-14), 12, 14, 22, 23, 24 & 42.

NS2 - CHECKING FOR FUEL SPRAY

Remove air cleaner cover and have someone crank engine while checking for fuel spray from injector. If fuel spray is a slow steady stream of fuel from injector, go to NS3 - CODE 88 . If there is no fuel spray, go to NS9 - CODE 26 OR 27 . If injector is spraying excessive fuel, go to NS13 - CHECKING INJECTOR .

Look For Fuel Spray. Scheme 61

NS3 - CODE 88

Connect diagnostic readout tool to engine harness connector. Turn ignition switch on, off, on, off, on within 5 seconds. If code 88 appears on readout tool, go to NS4 - CHECKING FOR FOULED PLUGS . If code 88 does not appear on readout tool, logic board is defective. Replace engine control module.

Diagnostic Readout Tool. Scheme 62

NS4 - CHECKING FOR FOULED PLUGS

Remove spark plugs and check tips for wet fuel. If spark plug tips are not wet from fuel go to NS5 - TIMING CHECK . If spark plug tips are wet with fuel, clean and reinstall. Attempt to restart engine.

Note. It is normal for spark plug tips to appear Black after engine is started cold.

Look For Wet Fuel. Scheme 63

NS5 - TIMING CHECK

1. Connect timing light to engine. Crank engine while observing timing marks. If timing is between zero and 16 degrees BTC, check compression and valve timing. If timing is not between zero and 16 degrees, go to next step.
2. With timing light connected, set timing to 10 degrees BTC during cranking. If engine starts, reset timing to specifications. If engine does not start, check compression and valve timing.

NS6 - CHECKING FOR CODE 43

Connect diagnostic readout tool to engine harness connector. Erase fault codes. Crank engine for 5 seconds and turn ignition off. Place system in diagnostic mode and record all codes set. If no fault codes are set (88-12-55), go to NS7 - CHECKING COIL . If code 43 (88-12- 43 -55) is set, go to NS8 - CHECKING ENGINE CONTROL MODULE .

Diagnostic Readout Tool. Scheme 64

Scheme 65

1. Connect diagnostic readout tool to engine harness connector. Connect an analog voltmeter to positive terminal of ignition coil and ground. Place system in ATM Test Mode 01. If voltmeter is within one volt of battery voltage, go to next step. If voltmeter indicates zero, check Dark Green/Black tracer wire of coil positive terminal for open. Repair or replace as necessary.
2. With diagnostic readout tool connected and system in ATM Test Mode 01, connect analog voltmeter to negative terminal of ignition and ground. If voltmeter reading is pulsating between 10-14 volts, replace ignition coil. If voltmeter is not pulsating, but reads above 10 volts, go to next step 3). If voltmeter is pulsating between 5-10 volts, replace ignition coil. If voltmeter is pulsating between zero and 2 volts, go to step 4).
3. Turn ignition off. Unplug the 14-way connector from engine control module. Connect an ohmmeter between negative terminal of ignition coil and cavity No. 12 of 14-way connector. If ohmmeter is showing continuity, power board is defective. Replace engine control module. If ohmmeter is not showing continuity, check Black/Yellow tracer wire of cavity No. 12 for open circuit. Repair or replace as necessary. NOTE: Before replacing engine control module, check cavity No. 12 of 14-way connector for proper connection. (Scheme 65): Ignition Coil & 14-Way Connector
4. Connect diagnostic readout tool to engine harness connector and turn ignition off. Disconnect wire from negative side of ignition coil. connect voltmeter to negative terminal of ignition coil and ground. Place system in ATM Test Mode 01. If voltmeter reading is above 10 volts, go to next step. If voltmeter reads between zero and 2 volts, replace ignition coil.
5. Disconnect coil negative wire and turn ignition off. Unplug 14-way connector from engine control module. Connect an ohmmeter between cavity No. 12 of 14-way connector and ground. If ohmmeter is not showing continuity, power board is defective. Replace engine control module. If ohmmeter is showing continuity, check Black/Yellow tracer wire of cavity No. 12 for short to ground.

Ignition Coil. Scheme 66

NS8 - CHECKING ENGINE CONTROL MODULE

1. With ignition off, connect diagnostic readout tool to engine harness connector. Disconnect ignition coil wire at distributor and place within 1/4" of good engine ground. Unplug 60-way connector from engine control module and connect one end of jumper wire to cavity No. 34. Turn ignition on. Press and hold ATM button on readout tool. Touch other end of jumper to good ground. Make and break this connection several times while observing ignition coil wire.
2. If there is spark at ignition coil wire as connection is made and broken, logic board is defective. Replace engine control module. If there is no spark at ignition coil wire as connection is made and broken, go to step 3). NOTE: Before replacing engine control module, ensure that terminal in cavity No. 34 of 60-way connector is not damaged.
3. Turn ignition off and unplug 60-way connector from engine control module. Remove jumper wire from cavity No. 34 of 60-way connector. Unplug 14-way connector from engine control module. Connect one lead of ohmmeter to cavity No. 34 and connect other lead of ohmmeter to cavity No. 13 of engine control module 14-way connector. If ohmmeter is showing continuity, power board is defective. Replace engine control module. If ohmmeter is not showing continuity, check wire for open circuit. Repair as necessary.

View From Terminal Ends. Scheme 67

Note. Before replacing engine control module, ensure that all terminals in cavities are not spread apart causing a poor connection.

NS9 - CODE 26 OR 27

Connect diagnostic readout tool to engine control module harness connector and erase fault codes. Crank engine for 5 seconds and turn ignition off. Place system in Diagnostic Mode. If no fault codes are set (88-12-55), or if code 26 is set (88-12- 26 -55), go to NS10 - CHECKING FUEL SUPPLY . If code 27 is set (88-12- 27 -55), go to NS12 - CHECKING SIGNAL TO INJECTOR .

Diagnostic Readout Tool. Scheme 68

Scheme 69

Scheme 70

1. Connect diagnostic readout tool to engine harness connector. Turn ignition off and install fuel pressure gauge in fuel supply hose at throttle body. Turn ignition switch to "ON" position. Press ATM button on diagnostic readout tool. If fuel gauge reading is 13.5-15.5 psi (0.95-1.09 kg/cm 2 ), go to next step. If fuel gauge reading is not 13.5-15.5 psi (0.95-1.09 kg/cm 2 ), go to step 3). CAUTION: Fuel may be under high pressure. System should be bled before hose is disconnected.
2. With diagnostic readout tool connected to engine harness connector, place system in Sensor Test Mode 05. If display reads between.5-1.5 volts, go to «NS11 - CHECKING FOR POWER TO FUEL INJECTOR»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system). If display reads more than 1.5 volts, replace TPS. NOTE: Divide display reading by 10 for actual reading. (Scheme 69): Fuel Pressure Supply Line (Scheme 70): Diagnostic Readout Tool
3. With ignition on and diagnostic readout tool connected to engine harness connector, press ATM button. Listen for intake fuel pump noise at rear of vehicle. If fuel pump is running, check fuel supply line and hoses for restrictions. Check for plugged filter or plugged intake fuel filter. If fuel pump isn't running, go to step 4).
4. Turn ignition on and connect diagnostic readout tool to engine harness connector. Raise vehicle on hoist and unplug intake fuel pump connector. Connect voltmeter to Dark Green/Black tracer wire of connector and ground. Press ATM button. If voltmeter reads within one volt of battery voltage, go to next step. If voltmeter reads zero, check wire for open circuit to wiring harness splice.
5. Raise vehicle on hoist and unplug intake fuel pump connector. Connect ohmmeter between Gray wire of fuel pump connector and ground. If ohmmeter is showing continuity, replace intake fuel pump. If ohmmeter is not showing continuity, check wire for open circuit to body ground.

Scheme 71

Scheme 72

1. Connect diagnostic readout tool to engine harness connector. Place system in Diagnostic Test Mode. Unplug fuel injector connector and connect analog voltmeter between terminals of injector connector. Select lowest voltage scale available on voltmeter. Place system in ATM Test Mode 02. If voltmeter is pulsating between zero and one volt go to step 4). If voltmeter is not pulsating, go to step 2). NOTE: If voltmeter is showing negative voltage, reverse leads at injector connector and repeat test.
2. Unplug injector connector and place system in ATM Test Mode 02. Connect voltmeter to Green/Black tracer wire of injector harness connector and ground. If voltmeter reads within one volt of battery voltage, go to next step. If voltmeter reads zero, check Green/Black tracer wire for open circuit to harness splice.
3. Turn ignition off and unplug injector connector. Unplug 14-way connector from engine control module. Connect ohmmeter between cavity No. 9 of 14-way connector and White wire of injector harness connector. If ohmmeter is indicating continuity, power board is defective. Replace engine control module. If ohmmeter is not indicating continuity, check wire in cavity No. 9 of 14-way connector for open circuit to injector. (Scheme 71): Fuel Injector Connector (Scheme 72): Fuel Injector Connector NOTE: Before replacing engine control module, ensure that all terminals in cavities are not spread apart causing a poor connection.
4. Connect diagnostic readout tool to engine control module harness connector and place system in Diagnostic Test Mode. Reconnect injector connector. Remove cap from top of injector. Connect analog voltmeter between terminals of injector cap. Select lowest voltage scale available on voltmeter and place system in ATM Test Mode 02. If voltmeter is pulsating between zero and one volt, replace fuel injector. If voltmeter is not pulsating, replace injector cap and wiring harness assembly.

Note. If voltmeter is showing negative voltage, reverse leads at injector cap connector and repeat test.

Note. Before replacing any components ensure that all terminals and connectors are not damaged causing an poor connection.

Scheme 73

Scheme 74

1. Connect diagnostic readout tool to engine control module harness connector. Turn ignition off and remove air cleaner. Unplug 60-way connector from engine control module. Connect one end of jumper wire to cavity No. 33. Plug in injector connector and turn ignition switch to "ON" position. Press ATM button on readout tool. Rapidly connect and disconnect other end of jumper wire to positive terminal of battery post. If fuel sprays from injector, logic board is defective. Replace engine control module. If fuel does not spray from injector, go to next step. NOTE: Before replacing engine control module, ensure that all terminals and connectors are not damaged causing an poor connection. (Scheme 73): View From Terminal End (Scheme 74): View From Terminal End
2. Turn ignition off and unplug 14-way connector from engine control module. Connect an ohmmeter between cavity No. 33 of 60-way connector and cavity No. 8 of 14-way connector. If ohmmeter indicates continuity, power board is defective. Replace engine control module. If ohmmeter does not indicate continuity, check wire in cavity No. 8 of 14-way connector for open circuit to 60-way connector.

Note. Before replacing engine control module ensure, that all terminals in cavities are not spread apart causing a poor connection.

NS13 - CHECKING INJECTOR

1. Connect diagnostic readout tool to engine harness connector. Remove air cleaner and unplug injector harness connector. Turn ignition on and press ATM button on readout tool. If fuel sprays from injector, remove injector and inspect lower "O" ring for damage. If "O" ring is okay, replace injector. If fuel does not spray from injector, go to next step.
2. Turn ignition off and unplug 60-way connector from engine control module. Reconnect injector connector and turn ignition on. Press ATM button. If fuel sprays from injector, power board is defective. Replace engine control module. If fuel does not spray from injector, logic board is defective. Replace engine control module.

Fuel Injector Connector. Scheme 75

Fuel Injector Connector & 60-Way Connector. Scheme 76

Note. Before replacing engine control module, check for excessive pressure in fuel system.

NS14 - CODES 11, 12, 14, 22, 23, 24 & 42

Connect diagnostic readout tool to engine harness connector and erase fault codes. Crank engine for 7 seconds. Turn ignition switch to "ON" position for 5 seconds before turning ignition off. Place system in Diagnostic Mode and record all codes set. If code 88 or code 00 was not set, go to NS15 - CHECKING THROTTLE POSITION SENSOR (TPS) . If code 11 (88- 11 -12-55) is set, go to NS16 - CHECKING DISTRIBUTOR PICK-UP . If code 42 (88- 42 -55) is set, go to NS17 - CHECKING ASD RELAY . If any of the following codes are set (88- 12-14-22-24 -55) or (88- 12-14-22-23-24 -55), check wire in cavity No. 4 of engine control module 60-way connector for an open circuit.

Scheme 77

Scheme 78

1. Turn ignition off and unplug TPS connector. Turn ignition switch to "ON" position. Connect voltmeter to Violet/White tracer wire at TPS connector and ground. If voltmeter reads at least 4.5 volts, go to next step. If voltmeter reads zero volts, go to step 3).
2. Turn ignition off and unplug 60-way connector from engine control module. Connect one lead of ohmmeter to system ground eyelet. Touch other end of ohmmeter to cavity No. 15 and No. 16 of 60-way connector. If ohmmeter is showing continuity with less than 1/2 ohm of resistance in both wires, logic board is defective. Replace engine control module. If ohmmeter is not showing continuity, check wires for open circuit to wiring harness splice. Replace engine control module. If ohmmeter is showing more than 1/2 ohm of resistance at one or both wires, check ground circuit for high resistance to system ground eyelet.
3. Turn ignition on and unplug TPS connector. Connect negative lead of voltmeter to ground and unplug MAP sensor connector. Touch positive lead of voltmeter to Violet/White tracer wire at TPS connector. If voltmeter reads at least 4.5 volts, replace MAP sensor. If voltmeter reads zero, go to next step.
4. Turn ignition off and unplug 60-way connector from engine control module. Connect negative lead of voltmeter to ground and turn ignition on. Touch positive lead of voltmeter to cavity No. 52 of engine control module 60-way connector. If voltmeter reads at least 8 volts, logic board is defective. Replace engine control module. If voltmeter reads zero, go to next step. NOTE: Before replacing any components ensure that all connector terminals are not spread apart or damaged. (Scheme 77): View From Terminal End (Scheme 78): Throttle Position Sensor Connector
5. Turn ignition on and unplug 60-way connector from engine control module. Connect negative lead of voltmeter to ground. Unplug distributor pickup harness connector. Touch positive lead of voltmeter to cavity No. 52 of engine control module 60-way connector. If voltmeter reads at least 8 volts, replace distributor pickup. If voltmeter reads zero, go to next step.
6. Unplug 60-way connector and distributor pickup connector. Turn ignition off and touch one end of ohmmeter to cavity No. 52 of 60-way connector. Touch other lead to Orange wire terminal of distributor harness connector. If ohmmeter is showing continuity, go to next step. If ohmmeter is not showing continuity, check Orange wire of cavity No. 52 for an open circuit to wiring harness splice.
7. Turn ignition off and unplug 14-way connector from engine control module. Connect negative lead of voltmeter to ground and turn ignition on. Touch positive lead of voltmeter to cavity No. 4 of engine control module 14-way connector. If voltmeter reads within one volt of battery voltage, go to next step. If voltmeter does not read within one volt of battery voltage, check Blue wire in cavity No. 4 of 14-way connector for an open circuit to wiring harness splice.
8. Turn ignition off and unplug 14-way connector from engine control module. Connect one lead of ohmmeter to system ground eyelet. Connect other lead of ohmmeter to cavities No. 6 and No. 7 of 14-way connector. If ohmmeter is showing continuity at both cavities with less than 1/2 ohm of resistance, power board is defective. Replace engine control module. If ohmmeter is not showing continuity at both cavities, check Black wires in cavities No. 6 and No. 7 of 14-way connector for an open circuit to wiring harness splice. Replace engine control module. If ohmmeter is showing continuity with resistance higher than 1/2 ohm, check ground circuit for high resistance to system ground eyelet.

Note. Before replacing any components ensure that all connector terminals are not spread apart or damaged.

Scheme 79

Scheme 80

1. Turn ignition off and unplug distributor pick-up harness connector. Remove coil wire from distributor and place 1/4" from good engine ground. Turn ignition switch to "ON" position. Connect jumper wire to distributor pickup harness connector cavity No. 2 and No. 3. Make and break this connection several times while observing coil wire. If there is spark at coil wire, go to next step. If there is no spark at coil wire, go to step 3).
2. Turn ignition on and unplug distributor pick-up harness connector. Connect voltmeter to cavity No. 1 of distributor pick-up harness and ground. If voltmeter reads at least 7 volts, replace distributor pick-up. If voltmeter reads zero, check wire in cavity No. 1 for open circuit to wiring harness splice. NOTE: Before replacing any components ensure that all connector terminals are not spread apart or damaged. (Scheme 79): Distributor Pick-Up Harness Connector (Scheme 80): Distributor Pick-Up Harness Connector
3. Turn ignition on and unplug distributor pickup harness connector. Connect positive lead of voltmeter to cavity No. 3 of distributor pickup harness connector. Connect negative lead of the voltmeter to cavity No. 2 of distributor pickup harness. If voltmeter reads at least 4 volts, replace engine control module. If voltmeter reads zero, go to next step.
4. Turn ignition on and unplug distributor pickup harness connector. Connect positive lead of voltmeter to cavity No. 3 of distributor pickup harness connector. Connect negative lead of the voltmeter to good engine ground. If voltmeter reads at least 4 volts, check wire in cavity No. 2 for an open circuit to wiring harness splice. If voltmeter reads zero, go to next step.
5. Turn ignition off and unplug distributor pickup harness connector. Unplug 60-way connector from engine control module. Connect ohmmeter between cavity No. 3 of distributor harness connector and cavity No. 47 of 60-way connector. If ohmmeter is not showing continuity, check Gray wire in cavity No. 47 of 60-way connector for an open circuit to distributor pickup harness connector. If ohmmeter is showing continuity, logic board is defective. Replace engine control module.

Note. Before replacing any components ensure that all connector terminals are not spread apart or damaged.

Scheme 81

Scheme 82

1. Connect diagnostic readout tool to engine harness connector. Connect voltmeter to Dark Blue/Yellow tracer wire of ASD relay 3-way connector and ground. Place system in ATM Test Mode 06. If voltmeter pulsates between zero and 12 volts while system is in ATM Test Mode 06, go to next step. If voltmeter reads within one volt of battery voltage and system cannot be placed into ATM Test Mode 06, go to step 6). If voltmeter reads zero to one volt steady and system cannot be placed in ATM Test Mode 06, go to step 4). NOTE: Diagnostic readout tool may go directly from code 55 to ATM Test 01 and then continue to cycle through all ATM tests without pressing ATM button.
2. Connect voltmeter to Red wire in ASD relay 3-way connector and ground. If voltmeter reads within one volt of battery voltage, go to next step. If voltmeter reads zero, check Red wire of 3-way connector for an open circuit to wiring harness splice.
3. Turn ignition off and connect one lead of jumper to Dark Green/Black tracer wire of ASD relay 3-way connector. Touch other end of jumper wire to Red wire of ASD relay connector. If fuel pump turns on, replace ASD relay. If fuel pump does not turn on, check Dark Green/Black tracer wire for an open circuit to wiring harness splice. (Scheme 81): Auto Shutdown Relay (Scheme 82): Auto Shutdown Relay Connector
4. Connect negative lead of voltmeter to ground and turn ignition off. Unplug single wire connector from ASD relay. Connect voltmeter to Dark Blue/White wire of ASD relay single wire connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, replace ASD relay. If voltmeter reads zero, go to next step.
5. Turn ignition off and unplug 14-way connector from engine control module. Connect ohmmeter between cavity No. 3 of 14-way connector and Dark Blue/White wire of ASD relay single wire connector. If ohmmeter does not show continuity, check Dark Blue/White wire in cavity No. 3 for an open circuit to ASD relay. If ohmmeter shows continuity, power board is defective. Replace engine control module. NOTE: Before replacing any components, ensure that all connector terminals are not spread apart or damaged.
6. Connect diagnostic readout tool to engine harness connector. Turn ignition off and unplug 60-way connector from engine control module. Connect voltmeter to cavity No. 58 of 60-way connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, check Dark Blue/Yellow tracer wire in cavity No. 58 of 60-way connector for an open circuit to ASD relay.

TROUBLE CODE-TO-TEST MENU

Scheme 83

Scheme 84

1. Turn ignition switch to "OFF" position. Tee a vacuum gauge into vacuum line at MAP sensor. Start engine and observe gauge with engine idling. Observe gauge while snapping throttle open and closed.
2. Gauge should read manifold vacuum with engine idling and should immediately drop toward zero when throttle is snapped open and closed. If vacuum is zero, repair vacuum supply line to throttle body. If vacuum drops slowly, repair restriction in vacuum supply line.
3. If vacuum gauge reads manifold vacuum and immediately drops toward zero, turn engine off. Unplug MAP sensor connector. Connect diagnostic readout tool to engine harness connector. Enter system into Sensor Test Mode 08. Voltage reading should be 4 volts. Divide readout tool display by 10 to get actual voltage. If readout tool display is zero volts, check wiring to engine control module.
4. If wiring is okay, replace the SMEC. If voltage is okay, connect a jumper wire between Dark Green/Red and Black/Light Blue wires of MAP sensor harness connector. If readout tool display is zero volts, go to step 6). If readout tool display is not zero volts, connect one end of jumper wire to negative battery terminal. (Scheme 83): Vacuum Gauge NOTE: Before replacing engine control module, ensure that wire of cavity No. 11 of 60-way connector is not shorted to ground.
5. Connect other end of jumper wire to Dark Green/Red wire in MAP sensor harness connector. If readout tool display is zero volts, repair Black/Light Blue wire in MAP sensor connector for an open circuit to wiring harness splice. If readout tool display is 5 volts, repair Dark Green/Red wire in MAP sensor harness connector for an open circuit to logic module. (Scheme 84): MAP Sensor Circuit
6. Connect a digital voltmeter to Violet/White wire of MAP sensor harness connector and ground. If voltmeter reading is at least 4 volts, check MAP sensor harness connector terminals to ensure they are not damaged, causing a poor connection. If terminals are okay, replace MAP sensor.
7. If voltmeter reading is zero volts, check Violet/White wire for an open circuit to wiring harness splice.

Scheme 85

1. With diagnostic readout tool connected to engine harness connector, start engine. Unplug speed sensor connector. Place system in Engine Running Test Mode 71. Connect a jumper wire between terminals of speed sensor harness connector.
2. Make and break this connection. As you make and break this connection, display on readout tool should change. If display changes, replace speed sensor. If display does not change, turn engine off. Connect an ohmmeter between cavity No. 48 of 60-way connector and White/Orange wire terminal of speed sensor harness connector. If ohmmeter is showing continuity go to next step. If ohmmeter is not showing continuity, check wire in cavity No. 48 for an open circuit to speed sensor harness connector. (Scheme 85): Speed Sensor Connector
3. Turn engine off. Unplug speed sensor and engine control module 60-way connector. Connect an ohmmeter between cavity No. 4 of 60-way connector and black wire terminal of speed sensor harness connector. If ohmmeter is showing continuity, logic board is defective. Replace engine control module. If ohmmeter is not showing continuity, check Black wire of speed sensor harness connector for open circuit to harness splice.

View From Terminal End & Speed Sensor Connector. Scheme 86

Note. Before replacing engine control module, ensure that wire of cavity No. 48 of 60-way connector is not damaged causing poor connection.

Scheme 87

Scheme 88

1. With diagnostic readout tool connected to engine harness connector, turn ignition switch to "OFF" position. Unplug oxygen sensor connector. Enter system into Sensor Test Mode 02. Divide reading on display by 10. If display reads at least.4 volt, go to next step. If display reads zero, logic board is defective. Replace engine control module. NOTE: Before replacing engine control module, ensure that wire of cavity No. 23 of 60-way connector is not damaged causing poor connection. (Scheme 87): Distributor Pick-Up Harness Connector (Scheme 88): Heated Oxygen Sensor Harness Connector & Battery
2. With O2 sensor disconnected, connect one end of jumper wire to Black wire of O2 sensor harness connector. Connect other end of jumper wire to battery positive terminal. If display does not read at least 5 volts, replace O2 sensor. If display reads.4 volt, check Black wire of O2 sensor connector for an open circuit to engine control module.

Scheme 89

Scheme 90

1. With diagnostic readout tool connected to engine, turn ignition off. Unplug connector from coolant sensor. Place system in Sensor Test Mode 04. Display should read 00°. If temperature reading is 260°, ensure wire to cavity No. 3 of 60-way connector is not shorted to ground. If wiring is okay, replace logic module (multiply reading on display by 10 for actual reading). (Scheme 89): Coolant Sensor Connector (Scheme 90): Coolant Temperature Sensor
2. If display reads correctly, connect jumper wire between terminals of coolant sensor connector. If display reads 260°, replace coolant sensor. If display reads 00°, connect one end of jumper wire to negative battery terminal. Connect other end of jumper wire to Tan/White wire terminal of coolant sensor harness connector.
3. Display should read 260°. If display reads 260°, repair Black/Light Blue wire of coolant sensor harness connector for open to wiring harness splice. If display reads 00°, repair Tan/White wire for open circuit to logic module.

Scheme 91

Scheme 92

1. With diagnostic readout tool connected to engine, disconnect throttle body temperature sensor connector (charge temperature sensor on turbo). Put system into Sensor Test Mode 03. Multiply display readings by 10 for actual readings. Display on readout tool should read 5 volts.
2. If display on readout tool is zero volts, or reads zero volts and then increases, ensure wiring to 60-way connector (cavity No. 21) is not shorted to ground. If wiring is okay, replace engine control module. If voltage reading is 5 volts, connect jumper wire between terminals of throttle body temperature sensor connector. Display on readout tool should read zero volts. (Scheme 91): Throttle Body Temperature Sensor Connector (Scheme 92): Throttle Body
3. If display is zero volts, replace throttle body temperature sensor. If display reads 5 volts, connect one end of jumper wire to negative battery terminal. Connect other end of jumper wire to Black/Red wire terminal of throttle body temperature sensor connector.
4. Display on readout tool should be zero volts. If display is zero volts, repair Black/Light Blue wire of throttle body temperature sensor connector for an open circuit to wiring harness splice. If display reads 5 volts, repair Black/Red wire of throttle body temperature sensor connector for an open circuit to logic module.

Scheme 93

Scheme 94

1. With diagnostic readout tool connected to engine harness connector, disconnect throttle position sensor connector. Put system into Sensor Test Mode 05. Divide display readings by 10 for actual readings.
2. Display should read 5 volts. If display reads zero volts, ensure wire in 60-way connector (cavity No. 21) is not shorted to ground. If wiring is okay, replace logic module. If voltage reading was 5 volts, connect jumper wire between Orange/Dark Blue and Black/Light Blue wires of throttle position sensor harness connector. Display on readout tool should read zero volts. If display reads zero volts, proceed to step 5).
3. If display reads 5 volts, connect one end of jumper wire to negative battery terminal. Connect other end of jumper wire to Orange/Dark Blue wire terminal of throttle position sensor harness connector. If display reads 5 volts, repair Orange/Dark Blue wire of the TPS harness connector for an open to logic module. (Scheme 93): Throttle Position Sensor (TPS) (Scheme 94): Throttle Body
4. If display reads zero volts, repair Black/Light Blue wire of throttle position sensor harness connector for an open circuit to the wiring harness splice.
5. If voltmeter reading was zero volts in step 2), connect a digital voltmeter to Violet/White wire of throttle position sensor harness connector and ground. Voltmeter should read at least 4 volts. If voltage reading is okay, ensure the TPS is installed correctly.
6. If sensor is installed correctly, replace throttle position sensor. If voltmeter reads zero volts, repair Violet/White wire for an open circuit to wiring harness splice.

Scheme 95

Scheme 96

1. Turn ignition switch to "OFF" position. Unplug 60-way connector from engine control module. Connect ohmmeter leads to cavities No. 17 and No. 18. If there is resistance, connect ohmmeter leads between cavities No. 19 and No. 20 of 60-way connector. (Scheme 95): View From Terminal End (Scheme 96): View From Terminal End
2. If ohmmeter is showing some resistance, logic board is defective. Replace engine control module. If ohmmeter is showing zero resistance, unplug AIS motor connector. If ohmmeter is showing an open circuit, replace AIS motor. If ohmmeter is showing resistance, repair wires to AIS motor for short circuit to each other.

Scheme 97

Scheme 98

1. Connect voltmeter to Pink/White wire of canister purge solenoid connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, turn ignition off and unplug the 60-way connector. Connect voltmeter to cavity No. 54 and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace the SMEC. If voltmeter reads zero, repair wire in cavity No. 54 for an open to canister purge solenoid. (Scheme 97): Canister Purge Solenoid Connector (Scheme 98): View From Terminal End
2. If voltmeter reads zero to one volt, unplug 60-way connector and turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace the SMEC. If voltmeter reads zero, connect voltmeter to Dark Blue wire of canister purge solenoid harness connector and ground. If voltmeter reads within one volt of battery voltage, replace canister purge solenoid. If voltmeter reads zero, repair Dark Blue wire of canister purge solenoid harness connector for an open circuit to wiring harness splice.

Scheme 99

Scheme 100

1. Connect voltmeter to Dark Blue/Orange wire of A/C cut-out relay single connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, turn on A/C button and turn ignition off. Unplug 60-way connector. Connect voltmeter to cavity No. 56 and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, repair wire in cavity No. 56 for an open circuit to A/C cut-out relay. NOTE: Wire of cavity No. 56 contains an diode. (Scheme 99): View From Terminal End (Scheme 100): A/C Cut-Out Relay
2. If voltmeter reads zero to one volt, turn ignition off and turn on A/C button. Unplug 60-way connector and turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, connect voltmeter to Dark Green wire of A/C cut-out relay 3-way connector and ground.
3. If voltmeter reads within one volt of battery voltage, replace A/C cut-out relay. If voltmeter reads zero volts, repair dark Green wire to A/C condenser fan relay 3-way connector for an open circuit.

Scheme 101

Scheme 102

1. Connect voltmeter to Dark Blue/Pink wire of radiator fan relay connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, turn ignition off and unplug the 60-way connector. Connect voltmeter to cavity No. 57 and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace the SMEC. If voltmeter reads zero, repair wire in cavity No. 57 for an open to radiator fan relay. (Scheme 101): Radiator Fan Relay (Scheme 102): View From Terminal End
2. If voltmeter reads zero to one volts after performing first test procedure in step 1), turn ignition off. Unplug 60-way connector and turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, go to next step.
3. With ignition on, connect voltmeter to White wire of radiator fan relay 3-way connector and ground. If voltmeter reads within one volt of battery voltage, replace radiator fan relay. If voltmeter reads zero, repair dark Blue wire of 3-way connector for an open circuit to wiring harness splice.

DR11 - CODE 44 - FUSED J2 CKT TO THE SMEC (SINGLE MODULE ENGINE CONTROLLER)

Turn ignition off and unplug 60-way connector. Connect voltmeter to cavity No. 12 of 60-way connector. Turn ignition on. If voltmeter is within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, repair Dark Blue/White wire of cavity No. 12 for an open circuit to the ASD relay single connector.

View From Terminal End. Scheme 103

CHARGING SYSTEM TROUBLE CODE-TO-TEST MENU

CHARGING SYSTEM TROUBLE CODE-TO-TEST MENU

CH1 - CODE 16 - BATTERY VOLTAGE SENSING CKT

Turn ignition off and unplug 60-way connector. Connect voltmeter to cavity No. 41 of 60-way connector. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, repair Red wire of cavity No. 41 for an open circuit to wiring harness splice.

Note. Before replacing engine control module, ensure that terminal in cavity is not damaged causing a poor connection.

View From Terminal End. Scheme 104

Scheme 105

Scheme 106

1. Connect diagnostic readout tool to engine harness connector. Turn ignition off and unplug 14-way connector from engine control module. Separate 14-way connector. Reconnect half of connector that contains cavities No. 1-7 to engine control module.
2. Connect positive lead of an analog voltmeter to cavity No. 14 in half of connector that is not connected to engine control module. Connect negative lead to cavity No. 11 of same connector. Place system in ATM Test Mode 09. If voltmeter is pulsating between zero and 12 volts, power board is defective. Replace engine control module. If voltmeter reads zero volts, go to next step. (Scheme 105): 14-Way Connector (Scheme 106): 14-Way Connector
3. Unplug 14-way connector with cavities No. 8-14, from engine control module. Turn ignition on and connect positive lead of voltmeter to cavity No. 14 of 14-way engine control module connector. Move negative lead of voltmeter to negative battery terminal. If voltmeter reads within one volt of battery voltage, go to next step. If voltmeter reads zero to one volt, repair alternator field circuit for short to ground.
4. Turn ignition off and unplug 60-way connector. Connect an ohmmeter between No. 14 of 60-way connector and ground. If ohmmeter does not show continuity, logic board is defective. Replace engine control module. If ohmmeter is showing continuity, repair Dark Green/Orange wire of cavity No. 14 for short to ground.

Note. Before replacing engine control module, ensure that terminal in cavity is not damaged causing a poor connection.

Scheme 107

Scheme 108

1. Connect diagnostic readout box to engine harness connector. Connect one end of voltmeter to a good engine ground. Put system in ATM Test Mode 09. Touch other lead to each of alternator field terminals. Check voltmeter reading. If voltmeter reads zero volts at both alternator field terminals, repair J2 circuit to alternator field for an open circuit to wiring harness splice.
2. If voltmeter reads battery voltage at one field terminal and is pulsating between zero and battery voltage at other terminal, check for improper alternator drive belt tightness. Check battery or alternator for normal operation. If voltmeter reads battery voltage at both field terminals, turn ignition off and unplug 14-way connector from engine control module. (Scheme 107): 14-Way Connector (Scheme 108): 14-Way Connector
3. Connect voltmeter to cavity No. 14 and turn ignition on. If voltmeter reads within one volt of battery voltage, go to step 4). If voltmeter reads zero, repair Dark Green wire of cavity No. 14 of 14-way connector for an open circuit to alternator.
4. Turn ignition off and separate the engine control module (SMEC) 14-way connector. Reconnect half of connector that contains cavities No. 1-7 to engine control module. Connect positive lead of analog voltmeter to cavity No. 14 in half of 14-way connector that is not connected to the SMEC. Connect negative lead of voltmeter to cavity No. 11 of same connector. Place system in ATM Test Mode 09.
5. If voltmeter is pulsating between zero and 12 volts, power board is defective. Replace engine control module. If voltmeter reads zero volts, turn ignition off and unplug 60-way connector from engine control module. Connect ohmmeter between cavity No. 11 of 14-way connector and cavity No. 14 of 60-way connector. If ohmmeter shows continuity, logic board is defective. Replace engine control module. If ohmmeter is not showing continuity, repair Dark Green/Orange wire of 60-way connector for an open circuit to 14-way connector.

CCS1 - CODES 15, 34, 12/34, 15/55 OR 12/15

1. Connect diagnostic readout tool to engine harness connector. Place system in Diagnostic Test Mode and record all codes set. If no fault codes are set (88-55 or 88-12-55), go to step 2). If code 34 is set (88-34-55 or 88-12-34-55), go to «CCS2 - SPEED CONTROL SERVO»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system) . If code 15 is set (88-15-55 or 88-12-15-55), perform DR3.
2. Place system in Sensor Test Mode 09. Ensure that speed control switch is in "OFF" position. While observing readout tool, move on/off switch to "ON" position. Press "SET" button and press "RESUME" button. Record all display readings. If display reads 00-10-01, control switch is okay. Perform «CCS3 - SPEED CONTROL SERVO CKT»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system) . If display reads blank-blank-blank, perform «CCS4 - SPEED CONTROL SERVO HARNESS CKT»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system) . If display reads blank-10-10, perform «CCS5 - SPEED CONTROL SERVO HARNESS CKT (CONT»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system) .). If display reads 00-00-00, perform «CCS6 - SPEED CONTROL SERVO HARNESS CKT (CONT»(/dodge/caravan/i-1984-1990/remont/testing-diagnostics/#25l-efc-system) .).

Cruise Control System Test 1 (CCS1). Scheme 109

Scheme 110

Scheme 111

1. Connect diagnostic readout tool to engine harness connector. Connect voltmeter to Tan/Red wire of speed control servo harness connector and ground. Place system in ATM Test Mode 08. Turn speed control switch to "ON" position. If voltmeter is pulsating between zero and 12 volts, vacuum solenoid is okay. Go to next step. If voltmeter reads within one volt of battery voltage, go to step 5). If voltmeter reads between zero and one volt, go to step 6).
2. Turn ignition off and connect voltmeter to Light Green/Red wire of speed control servo harness connector and ground. Turn ignition on and turn speed control switch to "ON" position. If voltmeter reads within one volt of battery voltage, go to step 3). If voltmeter reads between zero and one volt, go to step 4).
3. Turn ignition off and unplug 60-way connector from engine control module. Connect voltmeter to cavity No. 60 of 60-way connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads between zero and one volt, repair wire of cavity No. 60 for an open circuit to speed control servo connector. NOTE: Before replacing engine control module, always ensure that cavity terminals are okay and not damaged. Also check for proper connections and wiring.
4. Connect voltmeter to Light Green/Red wire of speed control servo harness and ground. Unplug 60-way connector and turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads between zero and one volt, repair wire of cavity No. 60 for short circuit to ground from logic board to speed control servo connector. (Scheme 110): View From Terminal End (Scheme 111): Speed Control Servo Connector
5. Turn ignition off and unplug 60-way connector. Connect voltmeter to cavity No. 53 of 60-way connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads between zero and one volt, repair wire of cavity No. 53 for open circuit to speed control servo connector.
6. Connect voltmeter to Tan/Red wire of speed control servo harness and ground. Unplug 60-way connector and turn ignition on. If voltmeter reads within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads between zero and one volt, go to next step.
7. With speed control switch in "ON" position, turn ignition off. Connect voltmeter to Dark Blue/Red wire of speed control servo harness connector and ground. Turn ignition on. If voltmeter reads within one volt of battery voltage, replace speed control servo. If voltmeter still reads between zero and one volt, go to next step.
8. Connect voltmeter to Dark Blue/Red wire of brake switch harness connector and ground. If voltmeter reads within one volt of battery voltage, repair Dark Blue/Red wire for an open circuit to speed control servo. If voltmeter still reads between zero and one volt, go to next step.
9. Connect voltmeter to Yellow/Red wire of brake switch harness connector and ground. If voltmeter reads within one volt of battery voltage, replace brake switch. If voltmeter still reads zero, repair Yellow/Red wire for an open circuit to wiring harness splice.

Scheme 112

Scheme 113

1. Turn ignition off and unplug speed control servo connector. Connect an ohmmeter between Black wire of speed control servo harness connector and ground. If ohmmeter is showing continuity, go to next step. If ohmmeter is not showing continuity, repair Black wire for an open circuit to wiring harness splice.
2. Connect diagnostic readout tool to the engine harness connector. Place system in Switch Test Mode and press brake pedal. If display changes, go to step 4). If display does not change, proceed to the next step.
3. Place gear selector in "PARK", "NEUTRAL" and "DRIVE", while observing diagnostic readout tool. If display changes as gear selector is moved, go to step 6). If display does not change as gear selector is moved, go to next step.
4. Turn ignition off and unplug 60-way connector. Connect an ohmmeter to cavity No. 30 of 60-way connector and ground. Unplug battery quick disconnect and turn ignition on. Place gear selector in "PARK", "NEUTRAL" and "DRIVE" and observe position. If ohmmeter is showing continuity in all gear positions, check wire of cavity No. 30 for a short to ground. Also check for a bad neutral switch. (Scheme 112): 60-Way Connector (Scheme 113): View From Terminal End
5. If ohmmeter shows no continuity in all positions of gear selector, repair wire of cavity No. 30 for an open circuit to neutral switch. If ohmmeter reads Park (continuity), Reverse (no continuity), Neutral (continuity) and Drive (no continuity), logic board is defective. Replace engine control module.
6. Reconnect speed control servo connector and connect diagnostic readout tool to engine harness connector. Unplug speed control servo vacuum supply hose from power brake booster. Connect an auxiliary vacuum supply to booster. Place system in ATM Test Mode 08 and apply vacuum to servo.
7. If the system turns on/off as vacuum is being applied and throttle is opening and closing, check vacuum supply to speed control servo. Also check speed sensor operation using Engine Running Test Mode 71. If system turns on/off while vacuum is being applied and throttle is not opening and closing, replace speed control servo.

Note. Before replacing servo, ensure that speed control cable is properly adjusted or is not damaged. Also ensure that vacuum hoses are not leaking or restricted.

Scheme 114

Scheme 115

1. Connect diagnostic readout tool to engine harness connector. Place system in Sensor Test Mode 09 and turn speed control switch to "ON" position. Connect jumper wire between Dark Blue/White wire and Yellow/Red wire of speed control switch harness connector. Do not disconnect speed control switch connector. If 00 is displayed, replace speed control switch. If display is blank, go to next step.
2. Turn ignition off. Connect negative lead of voltmeter to ground. Connect positive lead to Dark Blue/White wire of speed control switch harness connector. Turn ignition on. If voltmeter is within one volt of battery voltage, go to next step. If voltmeter reads zero, repair Dark Blue/White wire for an open circuit to fuse box. (Scheme 114): Voltmeter (Scheme 115): Jumper
3. Turn ignition off and unplug 60-way connector. Connect negative lead of voltmeter to ground and positive lead to cavity No. 8 of 60-way connector. Turn ignition on. If voltmeter is within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, repair Yellow/Red wire of cavity No. 8 for an open circuit to speed control switch.

Note. Do not disconnect speed control switch.

Scheme 116

Scheme 117

1. Connect jumper wire between Dark Blue/White wire and Brown/Red wire of speed control switch harness connector. If 00 is displayed, replace speed control switch. If 10 is displayed, go to next step. (Scheme 116): View From Terminal End (Scheme 117): Jumper
2. Turn ignition off and unplug 60-way connector. Connect negative lead of voltmeter to ground and positive lead to cavity No. 9 of 60-way connector. Turn ignition on. If voltmeter is within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, repair Brown/Red wire of cavity No. 9 for an open circuit to speed control switch.

Scheme 118

Scheme 119

1. Connect diagnostic readout tool to engine harness connector. Place system in Sensor Test Mode 09 and turn speed control switch to "ON" position. Connect jumper between White wire and Dark Blue/White wire of speed control switch harness connector. If 01 is displayed, replace speed control switch. If 00 is displayed, proceed to the next step. NOTE: Do not disconnect speed control switch. (Scheme 118): View From Terminal End (Scheme 119): Jumper
2. Turn ignition off and unplug 60-way connector from engine control module. Connect negative lead of voltmeter to ground and positive lead to cavity No. 7 of 60-way connector. Turn ignition on and press "RESUME" switch. If voltmeter is within one volt of battery voltage, logic board is defective. Replace engine control module. If voltmeter reads zero, repair White wire of cavity No. 10 for an open circuit to speed control switch.

FUEL SYSTEM PRESSURE RELEASE

Note. The fuel system is under constant pressure. Before servicing fuel system ensure that pressure is released.

Removal & Installation

1. Loosen gasoline cap in order to release tank pressure. Remove wiring harness connector from injector.
2. Ground one terminal of injector. Connect a jumper wire to second terminal and energize injector by touching other end of jumper to battery positive terminal. This will release system pressure. NOTE: DO NOT energize injector longer than 10 seconds or damage may result to fuel injector.
3. Remove jumper wires and proceed with fuel system service.

Removal

1. Remove air cleaner and perform fuel system pressure release. Disconnect negative battery cable. Disconnect all vacuum hoses and electrical connectors.
2. Remove the throttle cable. Remove the speed control cable and transmission kickdown cable (if equipped). Remove return spring and fuel lines. Remove throttle body mounting screws. Remove the throttle body.

Note. Never use silicone lubricants on "O" rings or seals, as damage may result.

Installation

Using a new gasket, mount throttle body to intake manifold. Reverse removal procedure to complete installation.

1. Remove air cleaner and perform fuel system pressure release. Disconnect negative battery cable. Remove 3 screws attaching pressure regulator to throttle body. CAUTION: Place a shop towel around fuel inlet chamber to contain any fuel remaining in the system.
2. Pull pressure regulator from throttle body. Carefully remove "O" ring from pressure regulator and remove old gasket.

Install new gasket and "O" ring. Reverse removal procedure and check regulator for leaks to complete installation.

1. Remove air cleaner assembly and perform fuel system pressure release. Disconnect negative battery cable. Remove pressure regulator.
2. Remove screw holding down injector cap. Using 2 small screwdrivers, lift cap off injector using slots provided. Place a small screwdriver in hole in front of electrical connector.
3. Gently pry injector from pod. Ensure that injector lower "O" ring has been removed from pod.

Install new "O" ring on injector. The new injector should already have new "O" ring installed. Apply a light coating of caster oil or petroleum jelly on "O" rings. Reverse removal procedure to complete installation.

Note. Ensure that injector and cap are keyed in the proper position.

Disconnect negative battery cable and remove air cleaner. Disconnect 3-way connector at TPS. Remove 2 screws attaching TPS to throttle body. Pull TPS off throttle shaft.

Reverse removal procedure to install. Tighten screws to 20 INCH lbs. (2 N.m).

Remove air cleaner and disconnect throttle cables from throttle body linkage. Remove 2 screws from throttle cable bracket and lay bracket aside. Disconnect wiring and unscrew sensor.

Apply heat transfer compound to tip portion of new sensor. Reverse removal procedure to complete installation.

Remove air cleaner and negative battery cable. Disconnect the 4-pin connector. Remove temperature sensor from throttle housing. Remove 2 screws and remove AIS motor from throttle body housing. Ensure that "O" rings are removed with AIS motor.

Ensure that pintle is in retracted position. If pintle measures more than 1" (25 mm), it must be retracted using ATM test code 03. Battery should be connected for this procedure. Replace all "O" rings and reverse removal procedure to complete installation.

Remove air cleaner duct from SMEC and remove battery. Remove 2 mounting screws and wiring connectors from module. Remove module. To install, reverse removal procedure.

2.5L CEC Wiring Diagram. Scheme 120

See also:
• NS2 - CHECKING FOR FUEL SPRAY
• NS6 - CHECKING FOR CODE 43
• NS14 - CODES 11
• NS3 - CODE 88
• NS9 - CODE 26 OR 27
• NS13 - CHECKING INJECTOR
• NS4 - CHECKING FOR FOULED PLUGS
• NS5 - TIMING CHECK
• NS7 - CHECKING COIL
• NS8 - CHECKING ENGINE CONTROL MODULE