ENGINE CONTROL SYSTEM OPERATION INSPECTION [G6]

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Main Relay Operation Inspection

1.  Verify that the main relay clicks when the ignition switch turned to the ON position and off.

•  If there is no operation sound, inspect the following.
―  Main relay (See MAIN RELAY INSPECTION [G6].)
―  Wiring harness and connector between ignition switch and main relay


Intake Manifold Vacuum Inspection

1.  Verify the air intake hoses are installed properly.

2.  Start the engine and idle it.

3.  Disconnect the vacuum hose between the intake manifold and purge solenoid valve from the intake manifold side.

4.  Connect a vacuum gauge to the intake manifold and measure the intake manifold vacuum. (See INTAKE MANIFOLD VACUUM INSPECTION [G6])

•  If not as specified, inspect the following.
―  Air suction at throttle body, intake manifold and PCV valve installation points
―  Fuel injector
―  Accelerator cable free play
―  Engine compression (See COMPRESSION INSPECTION [G6].)


Idle Air Control System Inspection


Engine coolant temperature compensation inspection

1.  Connect the M-MDS to the DLC-2.

2.  Access the following PIDs.

•  ECT
•  IAC
•  RPM

3.  Verify that the engine is in cold condition, then start the engine.

4.  Verify that the engine speed decreases as the engine warms up.

•  If the engine speed does not decrease or decreases slowly, inspect the following.
―  ECT sensor inspection
―  IAC valve inspection


Load compensation inspection

1.  Start the engine and run is during idle.

2.  Disconnect the IAC valve connector and verify that the engine rotation changes.

•  If the engine condition does not change, do as follows.
1.  Connect the IAC valve connector
2.  Connect the M-MDS to DLC-2.
3.  Verify that P0505 is not displayed.
•  If P0505 is shown, perform the DTC inspection. (See DTC P0505 [G6].)
4.  Change the duty value of the IAC valve to 100% using simulation function of the IAC PID.
5.  Verify that the idle speed increases.
•  If the idle speed increases, replace the PCM.
•  If the idle speed does not change, inspect the following.
―  IAC valve air passage
―  Open or short circuit in wiring harness between IAC valve terminals and PCM terminals 2W

3.  Warm up the engine to normal operating temperature and run it at idle.

4.  Access the following PIDs.

•  ACSW
•  IAC
•  PSP
•  RPM

5.  Verify that the engine speed is within the specification under each load condition. (See ENGINE TUNE-UP [G6])

•  If not as specified under each load condition, inspect the following.
―  Refrigerant pressure switch (low, high) and related wiring harness (See REFRIGERANT PRESSURE SWITCH INSPECTION.)
―  Fan switch and related wiring harness (See FAN SWITCH INSPECTION.)
―  PSP switch and related wiring harness (See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [G6].)

6.  Turn the electrical loads on and verify that the engine speed is within the specification. (See ENGINE TUNE-UP [G6].)


Fuel Line Pressure Inspection

Warning
•  Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death. Fuel can also irritate skin and eyes.
•  To prevent this, always complete the “BEFORE REPAIR PROCEDURE”. (See BEFORE REPAIR PROCEDURE [G6].)

1.  Disconnect the negative battery cable.

2.  Connect a fuel pressure gauge between the fuel filter and fuel distributor.

3.  Connect the negative battery cable.

Caution
•  Connecting the DLC terminals may possibly cause a malfunction. Carefully connect the specified terminals only.

4.  Short the DLC terminal F/P to body ground using a jumper wire.

5.  Turn the ignition switch on and measure the fuel line pressure.

Specification
270—310 kPa {2.7—3.2 kgf/cm2, 39—45 psi}

6.  Turn off the ignition switch and disconnect the jumper wire.

•  If the pressure is higher than specified, inspect the fuel pump maximum pressure. If normal, inspect fuel return hose or the pressure regulator for clogging.
•  If the pressure is lower than specified, measure the fuel line pressure while pinching the return hose.
―  If the fuel line pressure quickly increases, inspect the pressure regulator and PRC solenoid valve.
―  If fuel line pressure gradually increases, inspect the fuel pump maximum pressure. If the fuel pump maximum pressure is normal, inspect for clogging between fuel pump body and pressure regulator.


Fuel Pressure Hold Inspection

Warning
•  Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death. Fuel can also irritate skin and eyes.
•  To prevent this, always complete the “BEFORE REPAIR PROCEDURE”. (See BEFORE REPAIR PROCEDURE [G6].)

1.  Disconnect the negative battery cable.

2.  Connect a fuel pressure gauge between the fuel filter and fuel distributor.

3.  Connect the negative battery cable.

Caution
•  Connecting the wrong DLC terminals may possibly cause a malfunction. Carefully connect the specified terminals only.

4.  Short the DLC terminal F/P to body ground using a jumper wire.

5.  Turn the ignition switch on for approx. 10 s to operate the fuel pump body.

6.  Turn off the ignition switch and disconnect the jumper wire.

7.  Observe the fuel pressure after 5 min.

•  If the pressure is lower than specified, measure the fuel line pressure while pinching the return hose.
―  If the fuel line pressure holds, replace the pressure regulator. (See PRESSURE REGULATOR REMOVAL/INSTALLATION [G6].)
―  If the fuel line pressure does no hold, inspect the fuel leakage from fuel line and fuel injector.
Specification
More than 150 kPa {1.5 kgf/cm2, 21 psi}


Pressure Regulator Control Inspection

Warning
•  Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death. Fuel can also irritate skin and eyes.
•  To prevent this, always complete the “BEFORE REPAIR PROCEDURE”. (See BEFORE REPAIR PROCEDURE [G6].)

1.  Disconnect the negative battery cable.

2.  Connect a fuel pressure gauge between the fuel filter and fuel distributor.

3.  Connect the negative battery cable.

4.  Measure the fuel pressure under the following conditions.

Specifications

Condition

Fuel pressure [kPa {kgf/cm2, psi}]
Idling
210—250 {2.1—2.6, 30—36}
210—250
{2.1—2.6, 30—36}
270—310
{2.7—3.2, 39—45}
During 120 s of hot start
270—310 {2.7—3.2, 39—45}
After 120 s of hot start
210—250 {2.1—2.6, 30—36}
Judgment
Normal
Not Normal
(Perform Inspection 1)
Not Normal
(Perform Inspection 2)


Inspection 1

1.  Connect the M-MDS to DLC-2.

2.  Start the engine and let idle.

3.  Turn the test mode on using a simulation function.

4.  Turn the PRC solenoid valve from off to on using simulation function of FPRC PID and inspect if the fuel pressure changes.

•  If the pressure changes, inspect the following.
―  ECT, IAT and TP PIDs (See PCM INSPECTION [G6].)
•  If the pressure does not change, do as follows.
1.  Turn the test mode on using a simulation function.
2.  Turn the PRC solenoid valve from off to on using simulation function of FPRC PID and inspect if the operation sound of the valve is heard.
3.  If the operating sound is heard, inspect the pressure regulator.
4.  If the operating sound is not heard, inspect the PRC solenoid valve.


Inspection 2

1.  Connect the M-MDS to DLC-2.

2.  Turn the ignition switch to the ON position.

3.  Turn the PRC solenoid valve from off to on using simulation function of FPRC PID and inspect if the operating sound is heard.

•  If the operating sound is heard, inspect for a loose or damaged vacuum hose. (Pressure regulator—PRC solenoid valve —intake manifold)
•  If the operating sound is not heard, inspect the PRC solenoid valve.


Fuel Injector Operation Inspection

STEP

INSPECTION

RESULTS

ACTION
1
While cranking engine, inspect for fuel injector operating sound at each cylinder using a soundscope.
Is operating sound heard?
Yes
Fuel injector operation is normal.
No
Not heard at all cylinders:
Go to the next step.
Not heard at some cylinders:
Go to Step 3.
2
Carry out main relay operation inspection.
Is main relay operation normal?
Yes
Inspect following:
•  Fuel injector power system related wiring harnesses and connectors
•  PCM connectors
•  Fuel injector ground and related wiring harnesses and connectors
No
Repair or replace malfunctioning parts.
3
Change fuel injector connector of not operating fuel injector and operating fuel injector.
Is operating sound heard?
Yes
Go to the next step.
No
Replace fuel injector.
4
Are wiring harnesses and connectors of not operating fuel injector normal? (Open or short)
Yes
Inspect PCM terminal voltage of fuel injector signal.
No
Repair or replace malfunctioning parts.


Fuel Cut Control System Inspection

1.  Warm-up engine and idle it.

2.  Turn off the electrical loads and A/C switch.

3.  Connect the M-MDS to the DLC-2.

4.  Select RPM and INJ1, INJ2 PIDs.

5.  Monitor both PIDs while performing the following steps.

(1)  Depress the accelerator pedal and increase the engine speed to 4,000 rpm.
(2)  Release the accelerator pedal (brake pedal is not depressed) and verify that the fuel injector duration time is 0 ms, and 2—5 ms when the engine speed drops 1,200 rpm or less.
•  If not as specified, inspect the following.
―  ECT sensor inspection
―  Neutral/clutch switch inspection


Fuel Pump Operation Inspection

1.  Connect the M-MDS to the DLC-2.

2.  Remove the fuel-filler cap.

3.  Turn the ignition switch to the ON position.

4.  Turn the fuel pump relay from off to on using simulation function of FP PID and inspect if the operation sound is heard.

•  If no operation sounds is heard, proceed to next step.

5.  Measure the voltage at wiring harness-side fuel pump terminal B.

Specification
B+ (ignition switch is ON position)
•  If the voltage is as specified, inspect the following.
―  Fuel pump continuity
―  Fuel pump ground
―  Wiring harness between fuel pump relay and PCM terminal 1H
•  If not as specified, inspect the following.
―  Fuel pump relay (See MAIN RELAY INSPECTION [G6].)
―  Wiring harness and connector (Main relay—fuel pump relay—fuel pump)


Fuel Pump Control Inspection

1.  Connect the M-MDS to the DLC-2.

2.  Turn the ignition switch to the ON position.

3.  Turn the test mode on using a simulation function.

4.  Turn the fuel pump relay from off to on using simulation function of FP PID and inspect if the operating sound of the fuel pump relay is heard.

•  If no operating sound is heard, inspect the fuel pump relay.
•  If the fuel pump relay is normal, inspect the following.
―  Wiring harnesses and connectors (Main relay—fuel pump relay—PCM)


Ignition Timing Control Inspection

1.  Connect a timing light to the engine.

2.  Crank the engine.

3.  Verify that the timing mark (yellow) on the crankshaft pulley is within the specification. (See ENGINE TUNE-UP [G6].)

4.  Increase the engine speed and verify the ignition timing is advanced.

•  If the ignition timing is not advanced, carry out the following.
―  CMP sensor inspection
―  MAF sensor inspection


Spark Test

1.  Remove the fuel pump relay.

2.  Verify that each high-tension lead and connector is connected properly.

3.  Inspect the ignition system in the following procedure.

Warning
•  High voltage in the ignition system can cause strong electrical shock which can result in serious injury. Avoid direct contact to the vehicle body during the following spark test.

STEP

INSPECTION

ACTION
1
Remove high-tension lead from spark plug.
Hold high-tension lead with pliers installed 5—10 mm {0.20—0.39 in}from ground.
Crank the engine and verify that there is a strong blue spark. (Inspect each cylinder.)
Yes
Ignition system is normal.
No
Some cylinders do not spark:
•  Go to the next step.
All cylinders do not spark:
•  Go to Step 3.
2
Is high-tension lead resistance correct?
Yes
Inspect for cracks or damage of high-tension lead, distributor and ignition coil.
No
Replace the high-tension lead.
3
Does PCM or ignition coil connector have poor connection?
Yes
Repair or replace connector.
No
Go to the next step.
4
Is igniter normal?
Yes
Go to the next step.
No
Replace igniter.
5
Is ignition coil winding resistance normal?
Yes
Go to the next step.
No
Replace ignition coil.
6
Are distributor cap and rotor normal?
Yes
Go to the next step.
No
Replace distributor cap or rotor.
7
Are the following parts normal?
•  CMP sensor
•  PCM terminal 2E voltage
Specification
Approx. 1.5 V
Yes
Inspect for open or short circuit in wiring harness and connector of CMP sensor.
No
Repair or replace the malfunctioning part.


Purge Control System Inspection

1.  Start the engine and idle it.

2.  Disconnect the vacuum hose between the purge solenoid valve and the charcoal canister.

3.  Put a finger to the purge solenoid valve verify that there is no vacuum applied when the engine is cold.

•  If there is no vacuum, inspect the following.
―  Wiring harness and connectors (Purge solenoid valve—PCM terminal 2X)
―  Purge solenoid valve

4.  Warm up the engine to the normal operating temperature.

5.  Stop the engine.

6.  Connect the M-MDS to the DLC-2.

7.  Turn the ignition switch to the ON position.

8.  Access ECT PID.

9.  Verify that the engine coolant temperature is 60 °C {140 °F} or more.

•  If the ECT PID indicates 60 °C {140 °F} or more, carry out the ECT sensor inspection.

10.  Increase the duty value of the purge solenoid valve to 50% using simulation function of EVAPCP PID and inspect if the operation sound of the valve is heard.

•  If the operation sound is heard, inspect for the loose or damaged vacuum hose. (Intake manifold—purge solenoid valve—charcoal canister)
•  If the operation sound is not heard, perform the purge solenoid valve inspection.


A/C Cut-off Control System Inspection

1.  Start the engine.

2.  Turn the A/C switch and fan switch on.

3.  Verify that the A/C compressor magnetic clutch actuates.

•  If it does not actuate, go to symptom troubleshooting “No.22 A/C does not work sufficiently”. (See NO.22 A/C DOES NOT WORK SUFFICIENTLY [G6].)
Note
•  Specification of A/C cut-off control times is from 2 to 5 s.

4.  Fully open the throttle valve in a short period and verify that the A/C compressor magnetic clutch does not actuate.

•  If it actuates, inspect as following.
(1)  Connect the M-MDS to the DLC-2.
(2)  Turn the A/C switch off.
(3)  Turn the ignition switch to the ON position.
(4)  Turn the test mode on using a simulation function.
(5)  Turn the A/C relay from off to on using a simulation function of ACCS PID and inspect if the operation sound of the relay is heard.
•  If the operation sound is heard, inspect TP PID.
•  If the operation sound is not heard, inspect following.
―  A/C relay
―  Open circuit or short to ground in wiring harness and connectors (Main relay—A/C relay—PCM terminal 1J)
―  A/C related parts