Inspection Procedure 23
Transient, Mass Emission Tailpipe Test FailureCOMMENT
- 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 tool:
- MB991502: Scan Tool (MUT-II)
STEP 1. Check the exhaust gas with the engine at normal operating temperature.
Q: After enough warm up, was the exhaust gas checked enough?
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.
c. Check the exhaust system for missing or damaged parts.
Q: Are they normal?
YES: Go to Step 3.
NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 3. Check the drive ability.
1. Check if the malfunction symptom described on the symptom chart is occurring.
Q: Is the drive-ability normal?
YES: Go to Step 4.
NO: Refer to, Trouble Symptom Chart.
STEP 4. Using scan tool MB991502, read the diagnostic trouble code (DTC).
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 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 the DTC output?
YES: Refer to, Diagnostic Trouble Code Chart.
NO: Go to Step 5.
STEP 5. Check the ignition timing.
Refer to On-vehicle Service - Ignition Timing Check. <3.0L Engine>
Refer to On-vehicle Service - Ignition Timing Check. <3.5L Engine>
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 MB991502, check data list.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Check the following items in the data list. Refer to, Data List Reference Table.
a. Item 21: Engine Coolant Temperature Sensor.
b. Item 13: Intake Air Temperature Sensor.
c. Item 25: Barometric pressure Sensor.
d. Item 69: Right Bank Heated Oxygen Sensor (rear)
e. Item 59: Left Bank Heated Oxygen Sensor (rear)
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 7.
NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 7. Using scan tool MB991502, check data list item 39: Right Bank heated oxygen sensor (front).
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 39, Right Bank Heated Oxygen Sensor (front).
- Warm up the engine. When the engine is decelerated suddenly from 4000 r/min, the output voltage should increase from 200 mV or less to 600 - 1000 mV in a few seconds.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 8.
NO: Refer to, DTC P0132- Heated Oxygen Sensor Circuit High Voltage (bank 1, sensor 1), P0133 - Heated Oxygen Sensor Circuit Slow Response (bank 1, sensor 1), P0134 - Heated Oxygen Sensor Circuit No Activity Detected (bank 1, sensor 1)8.
STEP 8. Using scan tool MB991502, check data list item 11: Left Bank Heated oxygen sensor (front).
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 11, Left Bank Heated Oxygen Sensor (front).
- Output voltage should be 0.6 - 1.0 volts when sudden revving.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 9.
NO: Refer to, DTC P0152 - Heated Oxygen Sensor Circuit High Voltage (bank 2, sensor 1), P0153 - Heated Oxygen Sensor Circuit Slow Response (bank 2, sensor 1), P0154 - Heated Oxygen Sensor Circuit No Activity Detected (bank 2, sensor 1).
STEP 9. Using scan tool MB991502, check data list item 39: Right Bank Heated oxygen sensor (front).
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 39, Right Bank Heated Oxygen Sensor (front).
- Voltage should fluctuate between 0 - 0.4 volts and 0.6 - 1.0 volts while after the engine has been warmed.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 10.
NO: Go to Step 12.
STEP 10. Check the EGR system.
Refer to Emission Control System - EGR System Check.
Q: Is the EGR system normal?
YES: Go to Step 11.
NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 11. Using scan tool MB991502, check data list item 69: Right Bank Heated oxygen sensor (rear).
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 to the data reading mode for item 69, Right Bank Heated Oxygen Sensor (rear).
- Average voltage should be 0.6 volts or less, when idling.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 16.
NO: Replace the right bank heated oxygen sensor (front). Then confirm that the malfunction symptom is eliminated.
STEP 12. Using scan tool MB991502, check data list item 11: Left Bank Heated oxygen sensor (front).
1. Start the engine and run at idle.
2. Set scan tool MB991502 to the data reading mode for item 11, Left Bank Heated Oxygen Sensor (front).
- Warm up the engine. When the engine is decelerated suddenly from 4000 r/min, the output voltage should increase from 200 mV or less to 600 - 1000 mV in a few seconds.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 13.
NO: Go to Step 15.
STEP 13. Check the EGR system.
Refer to Emission Control System - EGR System Check.
Q: Is the EGR system normal?
YES: Go to Step 14.
NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 14. Using scan tool MB991502, check data list Item 59: Left Bank Heated oxygen sensor (rear).
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 to the data reading mode for item 59, Left Bank Heated Oxygen Sensor (rear).
- Average voltage should be 0.6 volts or less, when idling.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 16.
NO: Replace the left bank heated oxygen sensor (front). Then confirm that the malfunction symptom is eliminated.
STEP 15. Check the fuel pressure.
Refer to, Fuel Pressure Test.
Q: Is the fuel pressure normal?
YES: Go to Step 16.
NO: Repair or replace. Then confirm that the malfunction symptom is eliminated.
STEP 16. Check the following items.
1. Check the following items, and repair or replace the defective items.
a. Check the injectors for fuel leakage.
b. Check the ignition coil, spark plugs, spark plug cables.
c. Check compression pressure.
d. Check the positive crankcase ventilation system.
e. Check the evaporative emission control system.
2. Then check the malfunction symptom.
Q: Is the malfunction symptom is eliminated?
YES: The check is completed.
NO: Replace the catalytic converter. Then confirm that the malfunction symptom is eliminated.