Part 1

ENGINE CONTROL SYSTEM OPERATION INSPECTION [AJ]

Input Signal System Investigation Procedure
1. Find an unusual signal.
2. Locate its source.
3. Repair or replace the defective part.
4. Confirm that the unusual signal has been erased.

Finding unusual signals
While referring to ON-BOARD DIAGNOSTIC TEST [AJ], 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 unusual.
2. When recreating the problem, any sudden change in monitor input signals that is not consciously created by the driver can be judged as unusual.

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 done, 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 harness or terminal from water damage, leading to problems with the vehicle.






Variable resistance type 1 (APP sensor, TP sensor and EGR boost sensor)

Investigate the input signal system for variable resistance type 1
1. When you get an unusual signal, 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 M-MDS voltages, inspect the harness for open or short circuits.
- If the sensor and M-MDS voltages are the same, inspect for the following points concerning the sensor connector.
- If there are no problems, proceed to next investigation below.
- Female terminal opening is loose.
- Coupler (pin holder) damage
- Pin discoloration (blackness)

Investigate the standard power supply system 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 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 harness
- Harness/pin crimp is loose or disconnected.

Investigate the GND system 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 harness
- Female terminal opening is loose open or short circuit in harness
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected.






Variable resistance type 2 (MAF sensor)

Investigate the GND system 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 harness
- Female terminal opening is loose.
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected.

Investigate the input signal system for variable resistance type 2
1. When you get an unusual signal, 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 M-MDS voltages, inspect the harness for open or short circuits.
- If the sensor and 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.

Investigate the electrical supply system 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 harness
- Harness/pin crimp is loose or disconnected.






Thermistor type (IAT sensor and ECT sensor)

Investigate the input signal system for thermistor type
1. When you get an unusual signal, 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 M-MDS voltages, inspect the harness for open or short circuits.
- If the sensor and 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.

Investigate the GND system 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 harness
- Female terminal opening is loose.
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected.






VSS
1. Measure the #1 PCM terminal voltage and confirm that it is at 0 V or 5 V when the ignition switch at ON position and the engine at idle.
- If it is at 0 V or 5 V, intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING [AJ].) Intermittent Concern Troubleshooting
- If not, inspect the following points concerning the PCM connector.
- If there is no problem, inspect for the following:
- 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 and confirm that it is at 0 V or 5 V when the ignition switch at ON and the engine at idle.
- If it is at 0 V or 5 V, intermittent concern exists. (See INTERMITTENT CONCERN TROUBLESHOOTING [AJ].) Intermittent Concern Troubleshooting
- If not, inspect the following points concerning the sensor connector.
- If there is no problem, inspect for the following:
- Female terminal opening is loose.
- Coupler (pin holder) damage
- Pin discoloration (blackness)
- Harness/pin crimp is loose or disconnected.

3. Confirm that the #3 terminal switch voltage is at 0 V.
- If it is at 0 V, inspect the sensor. If necessary, replace the sensor.
- If necessary, replace the sensor.

- If not, inspect for the following:
- Open circuit in 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
- Harness and connector between ignition switch and main relay terminal A.
- Harness and connector between PCM terminal 1Z and main relay terminal E.

Intake Manifold Vacuum Inspection
1. Verify air intake hoses are installed properly.
2. Start the engine and run it at idle.
3. Measure the manifold vacuum using a vacuum gauge.
- If not as specified, inspect following:
- Air suction at throttle body, intake manifold and PCV valve installation points
- EGR valve (struck open)
- Fuel injector insulator
- Engine compression

NOTE: Air suction can be located by engine speed change when lubricant is sprayed on the area where suction occurs.

Electronic Throttle Control Inspection

Engine coolant temperature compensation inspection
1. Connect the M-MDS to the DLC-2.
2. Select the PID/DATA MONITOR AND RECORD function on the M-MDS display.
3. Select the following PIDs.
- ECT
- IAT
- RPM

4. Verify that the engine is in cold condition, then start the engine.
5. Verify that the engine speed decreases as the engine warm-up.
- If the engine speed does not decrease or decreases slowly, inspect the following:
- ECT sensor and related harness (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [AJ].)
- Throttle body and related harness (See THROTTLE ACTUATOR INSPECTION [AJ].)Testing and Inspection (See THROTTLE POSITION (TP) SENSOR INSPECTION [AJ].)Testing and Inspection

Load compensation inspection
1. Start the engine and run is at idle.
2. Connect the M-MDS to the DLC-2.
3. Verify that P0506, P0507 or P0511 are not displayed.
- If P0506, P0507 or P0511 are displayed, perform DTC inspection. (See DTC TABLE [AJ].) Diagnostic Trouble Code Descriptions

4. Select 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.
- If not as specified at specific load condition, inspect the following:
- A/C switch and related harness (See CLIMATE CONTROL UNIT INSPECTION [L3, AJ].)
- Fan switch and related harness (See CLIMATE CONTROL UNIT INSPECTION [L3, AJ].)
- PSP switch and related harness (See POWER STEERING PRESSURE (PSP) SWITCH INSPECTION [AJ].)

Throttle position (TP) sweep inspection
1. Connect the M-MDS to the DLC-2.
2. Turn ignition switch to ON position.
3. Verify that following DTCs are not displayed:
- P0121, P0122, P0123, P0221, P0222, P0223, P2100, P2101, P2102, P2103, P2107, P2108, P2119, P2122, P2123, P2127, P2128, P2135, P2136
- If any DTC is displayed, perform DTC inspection. (See DTC TABLE [AJ].) Diagnostic Trouble Code Descriptions

4. Access TP_REL PID.
5. Verify that the PID reading is within the CTP value.
- If the PID reading is out of range, perform the following:
- Remove air duct from throttle body.
- Verify that throttle valve moves when the accelerator pedal is depressed.
- If the throttle valve moves, inspect the following:

- TP sensor and related harness
- If the throttle valve does not move, inspect the following:

- Throttle actuator control motor and related harness

6. Gradually move the throttle valve and verify that the PID reading increases linearly.
- If the PID reading drops momentarily, inspect the following:
- TP sensor

7. Fully depress the accelerator pedal and verify that the PID reading is within the WOT value.
- If the PID reading is out of range, perform the following:
- Remove air duct from throttle valve body.
- Verify that the throttle valve moves when the accelerator pedal is depressed.
- If the throttle valve moves, inspect the TP sensor and related harness.
- If the throttle valve does not move, inspect the throttle actuator control motor and related harness.