Operation CHARM: Car repair manuals for everyone.
Home >> Mazda >> 2012 >> 6 L4-2.5L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Component Tests and General Diagnostics >> Engine Control System Operation Inspection >> Part 1

Part 1





ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.5]

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 ground to the ground 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.

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 to ON and off.

- If there is no operation sound, inspect the following:

- Main relay Relay Inspection
- Harness and connector between ignition switch and main relay
- Harness and connector between PCM terminal 1Q and main relay

Intake Manifold Vacuum Inspection

1. Verify air intake hoses are installed properly.

2. Start the engine and run it at idle.

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.

- If not as specified, inspect the following:

Specification
- More than 60 kPa {450 mmHg, 18 inHg}

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

- Air suction at throttle body, intake manifold and PCV valve installation points
- EGR valve (stuck open)
- Fuel injector insulator
- Engine compression Testing and Inspection

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:

- 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 P0506:00 or P0507:00 is not displayed. On-Board Diagnostic Test

- If the P0506:00 or 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 Manual Air Conditioner Full-Auto Air Conditioner
- Fan switch and related wiring harness Manual Air Conditioner Full-Auto Air Conditioner
- PSP switch and related wiring harness Testing and Inspection

Idle speed (ATX: P, N position, MTX: Neutral position)
- 600-700 rpm

Idle-up speed (ATX: P, N position, MTX: Neutral position)
- A/C on and: 600-850 rpm
- Electrical loads on: 650-750 rpm (MTX), 600-750 rpm (ATX)
- While turning steering wheel: 650-750 rpm

Throttle position (TP) sweep inspection

1. Connect the M-MDS to the DLC-2.

2. Switch the ignition to ON.

3. Verify that none of the following DTC are displayed: On-Board Diagnostic Test

- P0122:00, P0123:00, P0222:00, P0223:00, P0638:00, P2100:00, P2101:00, P2107:00, P2108:00, P2119:00, P2122:00, P2123:00, P2127:00, P2128:00, P2135:00, P2138:00

- If any one DTC is displayed, perform DTC inspection. Engine - DTC Table

4. Access the PCM PIDs APP1 and APP2 using the M-MDS. On-Board Diagnostic Test

5. Verify the APP1 and APP2 PIDs when the accelerator pedal released and depresses.
Specification

- Accelerator pedal released:

- APP1: Approx. 0.4 V
- APP2: Approx. 0.4 V

- Accelerator pedal depressed:

- APP1: Approx. 3.4 V
- APP2: Approx. 3.4 V

- If not as specified, inspect for the following harnesses and connectors:

- APP sensor terminal A-PCM terminal 1W
- APP sensor terminal B-PCM terminal 1AP
- APP sensor terminal C-PCM terminal 1AV
- APP sensor terminal D-PCM terminal 1AS
- APP sensor terminal E-PCM terminal 1AO
- APP sensor terminal F-PCM terminal 1AL

- If there is no malfunction, replace the accelerator pedal. Service and Repair

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.

- Neutral (MTX)
- P or N position (ATX)
- 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.) On-Board Diagnostic Test
- 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
- Neutral switch (MTX) Testing and Inspection
- CPP switch (MTX) Testing and Inspection
- TR switch (ATX) Testing and Inspection
- Brake switch No.1 Testing and Inspection
- Brake switch No.2 Testing and Inspection
- Communication between PCM and TCM (ATX) Initial Inspection and Diagnostic Overview

Variable Intake Air Control Operation Inspection

1. Start the engine.

2. Inspect the rod operation under the following condition: Rod operation





- 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 P0661:00 or P0662:00 is not displayed. On-Board Diagnostic Test

- If DTC P0661:00 or P0662:00 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 PCM PID ECT. On-Board Diagnostic Test

3. Verify that ECT PID is between 60 °C {140 °F} and 67 °C {153 °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 P2009:00 or P2010:00 is not displayed. On-Board Diagnostic Test

- If DTC P2009:00 or P2010:00 are shown, perform DTC inspection. 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 Shutter Valve Actuator Inspection
- Shutter valve stuck open or closed

Fuel Injector Operation Inspection

If simulation function of M-MDS is used:





If simulation function of M-MDS is used:





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. Access the PCM PID RPM. On-Board Diagnostic Test

5. Listen for the fuel injector operation sound at all cylinders using the soundscope and monitor both PIDs 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 fuel injector operation sound stops, and starts again when the engine speed drops below 1,200 rpm.

- If not as specified, inspect the following:

- ECT sensor and related wiring harness Testing and Inspection
- CPP switch and related wiring harness (MTX) Testing and Inspection
- Neutral switch and related wiring harness (MTX) Testing and Inspection
- TR switch and related wiring harness (ATX) Testing and Inspection

Fuel Pump Operation Inspection

1. Remove the fuel-filler cap.

2. Switch the ignition to ON.

3. Turn the fuel pump relay from off to on using the FP PID and inspect if the operation sound is heard. On-Board Diagnostic Test

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

4. Measure voltage at wiring harness side fuel pump terminal B

Specification
- B+ (Ignition at on)

- If the voltage is as specified, inspect the following:

- Fuel pump continuity
- Fuel pump ground
- Wiring harness between fuel pump relay and PCM terminal 1BG

- If not as specified, inspect the following:

- Fuel pump relay Relay 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 Relay Inspection
- Wiring harness and connectors (Main relay-Fuel pump relay-PCM terminal 1BG)

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.









EGR Control System Inspection

1. Crank the engine and verify that EGR valve operation (initial operation) sound is heard.

- If the operation sound is not heard, connect the M-MDS to the DLC-2 and verify that the DTC P0403:00 is shown. On-Board Diagnostic Test

- Perform DTC inspection. P0403

2. Start the engine and idle it.

3. Warm up the engine to normal operating temperature.

4. Access the following PCM PIDs: On-Board Diagnostic Test

- ECT, RPM, SEGRP_DSD, APP1, APP2, VSS

5. Idle the vehicle and verify that the SEGRP value is 0.

Continued in Part 2 Part 2
pro multis · About Operation CHARM