Part 1
ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF]Input Signal System Inspection Procedure
1. Find an irregular signal.
2. Locate source. (See Locating the source of unusual signals.)
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 [LF], 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 WDS or equivalent 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 EGR boost 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 WDS or equivalent 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 WDS or equivalent voltages, inspect the wiring harness for open or short circuits.
- If the sensor and the WDS or equivalent 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 (mass air flow (MAP) sensor and VSS)
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 WDS or equivalent 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 WDS or equivalent voltages, inspect the wiring harness for open or short circuits.
- If the sensor and the WDS or equivalent 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 WDS or equivalent 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 WDS or equivalent voltages, inspect the wiring harness for open or short circuits.
- If the sensor and the WDS or equivalent 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 (See RELAY INSPECTION.)
- Harness and connector between battery and main relay terminal A.
- Harness and connector between PCM terminal 10 and main relay terminal E.
Intake Manifold Vacuum Inspection [LF]
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.
- If not within the specification, perform the following inspections.
- Compression pressure.
- 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 WDS or equivalent 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.
- Electronic throttle body and related wiring harness.
Load compensation inspection
1. Start the engine and idle it.
2. Connect the WDS or equivalent to the DLC-2.
3. Verify that P0506, P0507, or P0511 is not displayed.
- If P0506, P0507 or P0511 are displayed, perform DTC inspection. (See DTC TABLE [LF].) Diagnostic Trouble Code Descriptions
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 toad condition. (See Engine TUNE-UP [LF].)
- If load condition is not as specified, inspect the following:
- A/C switch and related wiring harness (See CLIMATE CONTROL UNIT INSPECTION.)
- Fan switch and related wiring harness (See CLIMATE CONTROL UNIT INSPECTION.)
Throttle position (TP) sweep inspection
1. Connect the WDS or equivalent 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.
4. Access TPJ=REL PID.
5. Verify that the PID reading is within the CTP value.(See PCM INSPECTION [LF].)
- If the PID reading is out of range, perform the following;
- Remove the air duct from the throttle valve body.
- Verify that the throttle valve opens when the accelerator pedal is depressed.
- If the throttle valve opens, inspect the throttle position sensor and related wiring harness
- If the throttle valve does not open, inspect the throttle 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:
- Throttle position sensor
7. Fully depress the throttle pedal and verify that the PID reading is within WOT value. (See PCM INSPECTION [LF].)
- If the PID reading is out of range, perform the followings'
- Remove the air duct from throttle valve body
- Verify that the throttle valve opens when throttle pedal is depressed.
- If the throttle valve opens, inspect the throttle position sensor and related wiring harness
- If the throttle valve does not open, inspect the throttle actuator control motor and related wiring harness.