Part 1
ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF]
Part 1 of 2
Input Signal System Inspection Procedure
1. Find an irregular signal.
2. Locate source.
3. Repair or replace the malfunctioning part.
4. Confirm that the irregular signal is no longer detected.
Finding irregular signals
While referring to On-Board Diagnostic Test, use the PID/DATA monitor and record function to inspect the input signal system relating to the problem.
1. Start the engine and idle the vehicle. You can assume that any signals that are out of specification by a wide margin are irregular.
2. When recreating the problem, any sudden change in monitor input signals that is not intentionally created by the driver can be determined as irregular.
Locating the source of unusual signals
CAUTION:
- Compare the M-MDS monitor voltage with the measurement voltage using the digital measurement system function. If you use another tester, misreading may occur.
- When measuring voltage, attach the tester GND to the GND of the PCM that is being tested, or to the engine itself. If this is not performed, the measured voltage and actual voltage may differ.
- After connecting the pin to a waterproof coupler, confirming continuity and measuring the voltage, inspect the waterproof connector for cracks. If there are any, use sealant to fix them. Failure to do this may result in deterioration of the wiring harness or terminal from water damage, leading to problems with the vehicle.
Variable resistance type 1 (TP sensor and APP sensor)
Input signal system inspection for variable resistance type 1
1. When an irregular signal is detected, measure the #1 PCM terminal voltage.
- If the #1 terminal voltage and the M-MDS monitor voltage are the same, proceed to the next step.
- If there is a difference of 0.5 V or more, inspect for the following points concerning the PCM connector:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
2. Measure the #2 sensor terminal voltage.
- If there is a 0.5 V or more difference between the sensor and the M-MDS voltages, inspect the wiring harness for open or short circuits.
- If the sensor and the M-MDS voltages are the same, inspect for the following points concerning the sensor connector:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- If there are no problems, proceed to next investigation below.
Standard power supply system inspection for variable resistance type 1
- Confirm that the #3 terminal is at 5 V.
- If the measured voltage on the #3 terminal is 5 V, inspect the following points on the sensor connector.
- If there is no problem, inspect for the following:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- If the #3 terminal measures other than 5 V, inspect for the following:
- Open or short circuit in wiring harness
- Harness/pin crimp is loose or disconnected
GND system inspection for variable resistance type 1
- Confirm that terminal sensor #5 is at 0 V.
- If it is at 0 V, inspect the sensor.
- If necessary, replace the sensor.
- If not, inspect for the following:
- Open or short circuit in wiring harness
- Female terminal opening is loose causing an open or short circuit in wiring harness
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
Variable resistance type 2 (MAF sensor)
GND system inspection for variable resistance type 2
- Confirm that terminal sensor #4 is at 0 V.
- If it is at 0 V, inspect the sensor.
- If necessary, replace the sensor.
- If not at 0 V, inspect for the following:
- Open circuit in wiring harness
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
Input signal system inspection for variable resistance type 2
1. When an irregular signal is detected, measure the #1 PCM terminal voltage.
- If the #1 terminal voltage and the M-MDS monitor voltage are the same, proceed to the next step.
- If there is a difference of 0.5 V or more, inspect for the following points concerning the PCM connector:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
2. Measure the #2 sensor terminal voltage.
- If there is a 0.5 V or more difference between the sensor and the M-MDS voltages, inspect the wiring harness for open or short circuits.
- If the sensor and the M-MDS voltages are the same, inspect the following points concerning the sensor connector:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
- If there are no problems, proceed to next investigation below.
Electrical supply system inspection for variable resistance type 2
- Confirm that the sensor #3 terminal is B+.
- If the measured voltage on the #3 terminal is B+, inspect the following points on the sensor connector.
- If there is no problem, inspect for the following:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- If the #3 terminal measures other than B+, inspect the following:
- Open or short circuit in wiring harness
- Harness/pin crimp is loose or disconnected
Thermistor type (IAT sensor and ECT sensor)
Input signal system inspection for thermistor type
1. When an irregular signal is detected, measure the #1 PCM terminal voltage.
- If the #1 terminal voltage and the M-MDS monitor voltage are the same, proceed to the next step.
- If there is a difference of 0.5 V or more, inspect the following points concerning the PCM connector:
- Female terminal opening loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
2. Measure the #2 sensor terminal voltage.
- If there is a 0.5 V or more difference between the sensor and the M-MDS voltages, inspect the wiring harness for open or short circuits.
- If the sensor and the M-MDS voltages are the same, inspect the following points concerning the sensor connector:
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
- If there are no problems, proceed to next investigation below.
GND system inspection for thermistor type
- Confirm that terminal sensor #3 is at 0 V.
- If it is at 0 V, inspect the sensor. If necessary, replace the sensor.
- If not, inspect for the following:
- Open circuit in wiring harness
- Female terminal opening is loose
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected
Main Relay Operation Inspection
1. Verify that the main relay clicks when the ignition switch is turned to ON position and off.
- If there is no operation sound, inspect the following:
- Main relay Testing and Inspection
- Harness and connector between battery and main relay terminal E
- Harness and connector between PCM terminal 1Q and main relay terminal A
Intake Manifold Vacuum Inspection
1. Verify that the intake air hoses are installed securely.
2. Disconnect the vacuum hose connecting the intake manifold and the purge solenoid valve (purge solenoid valve side) and install the vacuum gauge.
3. Warm up the engine.
4. Measure the intake manifold vacuum while idling (no load) using the vacuum gauge. Component Tests and General Diagnostics
- If not within the specification, perform the following inspections:
- Compression pressure Testing and Inspection
- Air intake
- Each hose installation part
- Throttle body installation part
- Fuel injector installation part
- PCV valve installation part
- Dynamic chamber installation port
- Intake manifold installation part
Electronic Throttle Control System Inspection
Engine coolant temperature compensation inspection
1. Connect the M-MDS to the DLC-2.
2. Access the following PIDs:
- ECT
- IAT
- RPM
3. Verify that the engine is cold, 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 and related wiring harness Testing and Inspection
- Throttle body and related wiring harness Testing and Inspection
Load compensation inspection
1. Start the engine and idle it.
2. Connect the M-MDS to the DLC-2.
3. Verify that P0506, P0507, or P0511 is not displayed.
- If P0506, P0507 or P0511 are displayed, perform DTC inspection. DTC Table Engine
4. Access the RPM PID.
NOTE:
- Excludes temporary idle speed drop just after the loads are turned on.
5. Verify that the engine speed is within the specification under each load condition. Testing and Inspection
- If load condition is not as specified, inspect the following:
- A/C switch and related wiring harness
Climate Control Unit Inspection [Manual Air Conditioner]
Climate Control Unit Inspection [Full-Auto Air Conditioner]
- Fan switch and related wiring harness
Climate Control Unit Inspection [Manual Air Conditioner]
Climate Control Unit Inspection [Full-Auto Air Conditioner]
Throttle position (TP) sweep inspection
1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to the ON position.
3. Verify that none of the following DTC are displayed:
- P0122, P0123, P0222, P0223, P0638, P2101, P2107, P2108, P2109, P2112, P2119, P2122, P2123, P2127, P2128, P2135, P2138
- If any one DTC is displayed, perform DTC inspection. DTC Table Engine
4. Access the TP REL PID.
5. Verify that the PID reading is within the CTP value. Component Tests and General Diagnostics
- If the PID reading is out of range, perform the following:
- Remove the air duct from the throttle body.
- Verify that the throttle valve opens when the accelerator pedal is depressed.
- If the throttle valve opens, inspect the TP sensor and related wiring harness.
- If the throttle valve does not open, inspect the throttle valve actuator control motor and related wiring harness.
6. Gradually depress the throttle pedal and verify that the PID reading increases accordingly.
- If the PID reading drops momentarily, inspect the following:
- TP sensor
7. Fully depress the throttle pedal and verify that the PID reading is within WOT value. Component Tests and General Diagnostics
- If the PID reading is out of range, perform the followings:
- Remove the air duct from throttle body.
- Verify that the throttle valve opens when throttle pedal is depressed.
- If the throttle valve opens, inspect the TP sensor and related wiring harness.
- If the throttle valve does not open, inspect the throttle valve actuator control motor and related wiring harness.
Variable Intake air Control Operation Inspection
1. Start the engine.
2. Inspect the rod operation. Variable Intake Air Shutter Valve Actuator Inspection
- If the rod operation is not as specified, inspect as follows:
a. Stop the engine.
b. Connect the M-MDS to the DLC-2.
c. Verify that DTC P0661 or P0662 is not displayed.
- If DTC P0661 or P0662 is shown, perform DTC inspection. P0661 P0662
d. Inspect the variable intake air solenoid valve. Variable Intake Air Solenoid Valve Inspection
- If the variable intake air solenoid valve is not normal, replace the variable intake air solenoid valve. Service and Repair
- If the variable intake air solenoid valve is normal, inspect the following:
- Vacuum hose and vacuum chamber for looseness or damage
- Shutter valve actuator Variable Intake Air Shutter Valve Actuator Inspection
- Shutter valve stuck open or closed
Variable Tumble Control Operation Inspection
1. Connect the M-MDS to the DLC-2.
2. Access the ECT PID.
3. Verify that the ECT PID is below 60 °C {140 °F}.
4. Start the engine.
5. Inspect rod operation under the following conditions: Rod operation
- If the rod operation is not specified, inspect as follows:
a. Verify that DTC No. P2004, P2006, P2009 or P2010 is not displayed.
- If DTC No. P2004, P2006, P2009 or P2010 are shown, perform DTC inspection. P2004 P2006 P2009 P2010
b. Inspect the variable tumble solenoid valve. Variable Tumble Solenoid Valve Inspection
- If the variable tumble solenoid valve is not normal, replace the variable tumble solenoid valve. Service and Repair
- If the variable tumble solenoid valve is normal, inspect the following:
- Vacuum hose and vacuum chamber for looseness or damage
- Shutter valve actuator Variable Tumble Solenoid Valve Inspection
- Shutter valve stuck open or closed
Fuel Injector Operation Inspection
If simulation function of M-MDS is used:
Step 1-Step 4:
If simulation function of M-MDS is not used:
Step 1-Step 4:
Fuel Cut Control System Inspection
NOTE:
- This inspection has to perform after the Fuel Injector Operation Inspection.
If simulation function of M-MDS is used:
1. Warm up the engine and idle it.
2. Connect the M-MDS to the DLC-2.
3. Select the RPM and FUELPW1 PIDs.
4. Monitor the both PIDs while performing the following steps.
a. Depress the accelerator pedal and increase the RPM PID to 4,000 rpm.
b. Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the FUELPW1 PID is 0 ms, and 2-5 ms when the RPM PID drops below 1,200 rpm.
- If not as specified, inspect the following:
- ECT sensor and related harness Testing and Inspection
- Neutral switch and related harness Testing and Inspection
- CPP and related harness Testing and Inspection
If simulation function of M-MDS is not used:
1. Warm up the engine and idle it.
2. Measure the fuel injector control signal wave profile using the oscilloscope while performing the following steps.
a. Depress the accelerator pedal and increase the engine speed to 4,000 rpm.
b. Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the wave profile constant B+, and appears wave, when the engine speed drops below 2,200 rpm. Component Tests and General Diagnostics
- If not as specified, inspect the following:
- ECT sensor and related harness Testing and Inspection
- Neutral switch and related harness Testing and Inspection
- CPP and related harness Testing and Inspection
- TR switch and related wiring harness (AT) Testing and Inspection
Fuel Pump Operation Inspection
1. Remove the fuel-filler cap.
2. Turn the ignition switch to the ON position.
3. Turn the fuel pump relay from off to on using the FP PID and inspect if the operation sound is heard.
- If no operation sounds is heard, proceed to next step.
4. Measure voltage at wiring harness side fuel pump connector terminal B.
Specification
- B+ (Ignition switch at on)
- If the voltage is as specified, inspect the following:
- Fuel pump continuity
- Fuel pump GND
- Wiring harness between fuel pump relay and PCM terminal 1H
- If not as specified, inspect the following:
- Fuel pump relay Testing and Inspection
- Wiring harness connector (Main relay-fuel pump relay-fuel pump)
Fuel Pump Control System Inspection
1. Crank the engine and verify that fuel pump relay operation sound is heard.
2. If operation sound is not heard, inspect the following:
- Fuel pump relay Testing and Inspection
- Wiring harness and connectors (Main relay-fuel pump relay-PCM terminal 1H)
Continued in Part 2 Part 2