Part 1
ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7]
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)
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 sensor and 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 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 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 sensor and 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 CHT 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 sensor and 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 No.1 Operation Inspection
1. Verify that the main relay clicks when the ignition switch is turned to ON and off position.
- If there is no operation sound, inspect the following:
- Main relay No.1 Testing and Inspection
- Harness and connector between battery and main relay No.1 terminal E
- Harness and connector between PCM terminal 1AZ and main relay No.1 terminal A
Drive-by-Wire Control System Inspection
Engine coolant temperature compensation inspection
1. Connect the M-MDS to the DLC-2.
2. Access the following PCM PIDs: On-Board Diagnostic Test
- 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:
- CHT 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 P0506:00, P0507:00 is not displayed. On-Board Diagnostic Test
- If P0506:00, P0507:00 are displayed, perform DTC inspection. P0506 P0507
4. Access the PCM PID RPM. On-Board Diagnostic Test
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.
- If load condition is not as specified, inspect the following:
- A/C switch and related wiring harness Front Climate Control Unit Inspection
- Fan switch and related wiring harness Front Climate Control Unit Inspection
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: On-Board Diagnostic Test
- P0122:00, P0123:00, P0222:00, P0223:00, P2101:00, P2107:00, P2112:00, P2122:00, P2123:00, P2127:00, P2128:00, P2135:00
- If any one DTC is displayed, perform DTC inspection. Engine - DTC Table
4. Access the PCM PIDs TP1, TP2. On-Board Diagnostic Test
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. Testing and Inspection
- 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 Testing and Inspection
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. Testing and Inspection
- If the throttle valve does not open, inspect the throttle valve actuator control motor and related wiring harness.
Brake override system operation inspection
NOTE:
- If the brake override system operates normally after performing the following inspection, the PCM detects DTC P2299:00.
1. Start the engine and run it is idling.
2. Verify that the engine speed becomes less than 1,100 rpm under the following conditions.
- P or N position
- Engine speed of 1,150 rpm or more other than idle
- Brake pedal depressed
- If the engine speed becomes less than 1,100 rpm, clear the PCM DTC using the M-MDS. (System operation is normal.)
- If the engine speed does not become less than 1,100 rpm, inspect for the following parts, then repair or replace the malfunctioning part:
- APP sensor Testing and Inspection
- TR switch Testing and Inspection
- Brake switch No.1 Testing and Inspection
- Brake switch No.2 Testing and Inspection
- Communication between PCM and TCM Initial Inspection and Diagnostic Overview
Fuel Injector Operation Inspection
Fuel Cut Control System Inspection
NOTE:
- This inspection has to perform after the Fuel Injector Operation Inspection.
If simulation function of the M-MDS is used:
1. Warm up the engine and idle it.
2. Connect the M-MDS to the DLC-2.
3. Access the PCM PIDs RPM and FUELSYS1. On-Board Diagnostic Test
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 FUELSYS1 PID is OL, and CL. when the RPM PID drops below 1,200 rpm.
- If not as specified, inspect the following:
- CHT sensor and related harness Testing and Inspection
- TR switch and related wiring harness Testing and Inspection
If simulation function of the 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.
- If not as specified, inspect the following.
- CHT sensor and related harness Testing and Inspection
- TR switch and related wiring harness 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 PCM PID FP and inspect if the operation sound is heard.
- If no operation sounds is heard, proceed to next step.
4. Measure the voltage at fuel pump terminal B (wiring harness-side).
Specification
- B+ (Ignition switch at on)
- If the voltage is as specified, inspect the following:
- Fuel pump continuity
- Fuel pump ground
- If not as specified, inspect the following:
- Fuel pump relay Testing and Inspection
- Wiring harness connector (Battery positive terminal-Fuel pump relay-Fuel pump)
- Wiring harness between fuel pump relay and PCM terminal 1BI
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 (Ignition switch (IG1)-Fuel pump relay-PCM terminal 1BI)
Spark Test
1. Disconnect the fuel pump relay.
2. Verify that each ignition coil 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.
Purge Control System Inspection
If simulation function of the M-MDS is used:
1. Start the engine.
2. Disconnect the vacuum hose between purge solenoid valve and charcoal canister.
3. Put the finger to the purge solenoid valve and verify that there is no vacuum applied when the engine is cold.
- If there is a vacuum, inspect the following:
- Wiring harness and connectors (Purge solenoid valve-PCM terminal 2H)
- Purge solenoid vale (stuck open) Testing and Inspection
4. Connect the M-MDS to the DLC-2 and verify that the DTC P0443:00 is shown. On-Board Diagnostic Test
- Perform the DTC inspection. P0443
5. Access the PCM PID EVAPCP. On-Board Diagnostic Test
6. Increase the duty value of the purge valve to 50 % 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. Testing and Inspection
7. Warm up the engine to normal operating temperature.
CAUTION:
- While performing Step 8 with vehicle driving, always operate the vehicle in a safe and lawful manner.
- When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later.
8. Monitor the EVAPCP PID using the M-MDS, and drive the vehicle approx. 2,000 rpm for 30 s or more.
- If the EVAPCP PID is 0 %, inspect the following PCM PIDs:
- MAF, APP1, APP2, TP_REL and LOAD
If simulation function of the M-MDS is not used:
1. Start the engine.
2. Disconnect the vacuum hose between purge solenoid valve and charcoal canister.
3. Put the finger to the purge solenoid valve and verify that there is no vacuum applied when the engine is cold.
- If there is a vacuum, inspect the following:
- Wiring harness and connectors (Purge solenoid valve-PCM terminal 2H)
- Purge solenoid vale (stuck open) Testing and Inspection
4. Connect the M-MDS to the DLC-2 and verify that the DTC P0443:00 is shown. On-Board Diagnostic Test
- Perform the DTC inspection. P0443
5. Access the PCM PIDs EVAPCP and ECT. On-Board Diagnostic Test
6. Verify that the ECT PID is more than 78 °C {172 °F}.
- If the ECT PID reading indicates less than 78 °C {172 °F}, perform the ECT inspection.
7. Set the vehicle on the dynamometer or chassis roller.
WARNING:
- When the dynamometer or chassis roller is operating, there is a possibility that the operator may come into contact with or be caught up in the rotating parts, leading to serious injuries or death. When performing work while the dynamometer or chassis roller is operating, be careful not to come into contact with or caught up in any of the rotating parts.
8. Drive the vehicle approx. 2,000 rpm for 30 s or more.
- If there is no vacuum, inspect the following:
- Wiring harness and connector (Main relay No.1-Purge solenoid valve-PCM terminal 2H)
- Purge solenoid valve Testing and Inspection
- PCM PIDs MAF, APP1, APP2, TP_REL and LOAD
- If there is vacuum, inspect the following:
- Vacuum hose (Purge solenoid valve-Charcoal canister)
A/C Cut-off Control System Inspection
1. Start the engine.
2. Turn the A/C switch and the fan switch on.
3. Verify that the A/C compressor magnetic clutch actuates.
- If it does not actuate, go to symptom troubleshooting "NO.23 A/C DOES NOT WORK SUFFICIENTLY". No. 23 A/C Does Not Work Sufficiently
4. Depress the accelerator pedal to WOT and verify that the magnetic clutch does not actuate for 2-5 s.
- If it actuates, inspect as follows:
- A/C relay Testing and Inspection
- Open or short to ground circuit in wiring harness and connectors (A/C relay-PCM terminal 1W)
- A/C related parts
- PCM PIDs APP1 and APP2
Continued in Part 2 Part 2