Inspection Procedure 18
Inspection Procedure 18: Transient, Mass Emission Tailpipe Test Failure.COMMENT
- The test is failed when the air/fuel ratio is not controlled to the ideal air/fuel ratio. This occurs due to the feedback control by heated oxygen sensor signals, insufficient EGR flow rate, or deteriorated catalyst.
NOTE: If the three-way catalyst temperature is low when checking the exhaust gas, the three-way catalyst cannot sufficiently clean the emissions. Warm up the engine sufficiently before checking the exhaust, and check immediately.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of air/fuel ratio control system.
- Malfunction of the EGR system.
- Deteriorated catalyst.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Check the exhaust gas with the engine at normal operating temperature.
Q: Was the exhaust gas checked with engine warmed sufficiently?
YES : Go to Step 2.
NO : Check it again after enough warm up.
STEP 2. Check the following items.
1. Check the following items.
a. Check all vacuum hoses and connectors.
b. Check electrical wires and connectors for obvious problems.
Q: Are they normal?
YES : Go to Step 3.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 3. Check the driveability.
Q: Is the driveability normal?
YES : Go to Step 4.
NO : Refer to MFI Symptom Chart. Symptom Chart
STEP 4. Using scan tool MB991958, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Read the DTC.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?
YES : Refer to MFI Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions
NO : Go to Step 5.
STEP 5. Check the ignition timing.
Refer to Engine Mechanical, On-vehicle Service-Ignition Timing Check.
Q: Is the ignition timing normal?
YES : Go to Step 6.
NO : Check that the crankshaft position sensor and timing belt cover are in the correct position. Then confirm that the malfunction symptom is eliminated.
STEP 6. Using scan tool MB991958, check data list.
1. Turn the ignition switch to the "ON" position.
2. Check the following items in the data list. Refer to MFI Data List Reference Table. Datal List Reference Table
a. Item 6: Engine Coolant Temperature Sensor.
b. Item 5: Intake Air Temperature Sensor.
c. Item AC: Heated Oxygen Sensor Bank 1, Sensor 1 (right front)
d. Item AE: Heated Oxygen Sensor Bank 2, Sensor 1 (left front)
e. Item BB: Barometric Pressure Sensor
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?
YES : Go to Step 7.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 7. Using scan tool MB991958, check data list item AD: Heated oxygen sensor bank 1, sensor 2 (right rear).
1. Start the engine and run at idle.
2. Set scan tool MB991958 to the data reading mode for item AD, Heated Oxygen Sensor bank 1, sensor 2 (right rear).
a. Transaxle: "L" range
b. Drive with wide open throttle
c. Engine: 3,500 r/min
- The output voltages should be between 0.6 and 1.0 volt.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Go to Step 8.
NO : Refer to MFI P0137-Heated Oxygen Sensor Circuit Low Voltage (bank 1, sensor 2), P0137 DTC P0138-Heated Oxygen Sensor Circuit High Voltage (bank 1, sensor 2), P0138 DTC P0139-Heated Oxygen Sensor Circuit Slow Response (bank 1, sensor 2), P0139 DTC P0140-Heated Oxygen Sensor Circuit No Activity Detected (bank 1, sensor 2). P0140
STEP 8. Using scan tool MB991958, check data list item AF: Heated oxygen sensor bank 2, sensor 2 (left rear).
1. Start the engine and run at idle.
2. Set scan tool MB991958 to the data reading mode for item AF, Heated Oxygen Sensor bank 2, sensor 2 (left rear).
a. Transaxle: "L" range
b. Drive with wide open throttle
c. Engine: 3,500 r/min
- The output voltage should be between 0.6 and 1.0 volt.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Go to Step 9.
NO : Refer to MFI P0157-Heated Oxygen Sensor Circuit Low Voltage (bank 2, sensor 2), P0157 DTC P0158-Heated Oxygen Sensor Circuit High Voltage (bank 2, sensor 2), P0158 DTC P0159-Heated Oxygen Sensor Circuit Slow Response (bank 2, sensor 2), P0159 DTC P0160-Heated Oxygen Sensor Circuit No Activity Detected (bank 2, sensor 2). P0160
STEP 9. Check the EGR system.
Refer to Emission Control-Exhaust Gas Recirculation (EGR) System-General Information (Exhaust Gas Recirculation System).
Q: Is the EGR system normal?
YES : Go to Step 10.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 10. Check the fuel pressure.
Refer to MFI On-vehicle Service-Fuel Pressure Test. Testing and Inspection
Q: Is the fuel pressure normal?
YES : Go to Step 11.
NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 11. Check the spark plugs.
Refer to Engine Electrical, Ignition System-On-vehicle Service-Spark Plug Check And Cleaning.
Q: Are there any abnormalities?
YES : Replace the spark plug. Then confirm that the malfunction symptom is eliminated.
NO : Go to Step 12.
STEP 12. Check the ignition coil.
1. Remove the intake manifold.
2. Refer to Engine Electrical, Ignition System-On-vehicle Service-Ignition Coil Check.
Q: Are there any abnormalities?
YES : Replace the ignition coil. Then confirm that the malfunction symptom is eliminated.
NO : Go to Step 13.
STEP 13. Check the compression pressure.
Refer to Engine Mechanical, On-vehicle Service-Compression Pressure Check.
Q: Is the compression pressure normal?
YES : Go to Step 14.
NO : Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 14. Check the positive crankcase ventilation valve.
Refer to Emission Control-Positive Crankcase Ventilation System-Positive Crankcase Ventilation System Check. Testing and Inspection
Q: Is the positive crankcase ventilation valve?
YES : Go to Step 15.
NO : Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 15. Check the purge control system.
Refer to Emission Control-Evaporative Emission Control System-Purge Control System Check (Purge Flow Check). Purge Flow Check
Q: Is the purge control system normal?
YES : Go to Step 16.
NO : Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 16. Check the following items.
1. Check the following items.
a. Check the injectors for fuel leakage.
b. Check if the injectors are clogged.
Q: Are there any abnormalities?
YES : Replace it. Then confirm that the malfunction symptom is eliminated. Then confirm that the malfunction symptom is eliminated.
NO : Replace the catalytic converter. Then confirm that the malfunction symptom is eliminated.