Inspection Procedure 22
INSPECTION PROCEDURE 22: 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.
1. Check all vacuum hoses and connectors.
2. Check electrical wires and connectors for obvious problems.
3. Check the exhaust system for missing or damaged parts.
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 Trouble 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 the DTC set?
YES Refer to Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI).
NO Go to Step 5.
STEP 5. Check the ignition timing.
Testing and Inspection.
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.
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)Check the following items in the data list. Refer to Data List Reference Table Data List Reference Table.
4. Item 6: Engine Coolant Temperature Sensor.
5. Item 5: Intake Air Temperature Sensor.
6. Item AD: Cylinder 1, 4 Heated Oxygen Sensor (rear)
7. Item AF: Cylinder 2, 3 Heated Oxygen Sensor (rear)
8. Item BB: Barometric Pressure Sensor
(4)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 AC: Cylinder 1, 4 Heated oxygen sensor (front).
(1)Start the engine and run at idle.
(2)Set scan tool MB991958 to the data reading mode for item AC, Cylinder 1, 4 Heated Oxygen Sensor (front).
- Warm up the engine. When the engine is 2,500 r/min, the output voltage changes repeatedly between 0.4 volt or less and 0.6 - 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 DTC P0131 - Cylinder 1, 4 Heated Oxygen Sensor (front) Circuit Low Voltage P0131, DTC P0132 - Cylinder 1, 4 Heated Oxygen Sensor
(front) Circuit High Voltage P0132, DTC P0133 - Cylinder 1, 4 Heated Oxygen Sensor (front) Circuit Slow Response P0133, DTC P0134 - Cylinder 1, 4 Heated Oxygen Sensor (front) Circuit No Activity Detected P0134.
STEP 8. Using scan tool MB991958, check data list item AE: Cylinder 2, 3 Heated oxygen sensor (front).
(1)Start the engine and run at idle.
(2)Set scan tool MB991958 to the data reading mode for item AE, Cylinder 2, 3 Heated Oxygen Sensor (front).
- Warm up the engine. When the engine is 2,500 r/min, the output voltage changes repeatedly between 0.4 volt or less and 0.6 - 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 DTC P0151 - Cylinder 2, 3 Heated Oxygen Sensor (front) Circuit Low Voltage P0151, DTC P0152 - Cylinder 2, 3 Heated Oxygen Sensor
(front) Circuit High Voltage P0152, DTC P0153 - Cylinder 2, 3 Heated Oxygen Sensor (front) Circuit Slow Response P0153, DTC P0154 - Cylinder 2, 3 Heated Oxygen Sensor (front) Circuit No Activity Detected P0154.
STEP 9. Using scan tool MB991958, check data list item AD: Cylinder 1, 4 Heated oxygen sensor (rear).
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)Start the engine and run at idle.
(3)Set scan tool MB991958 to the data reading mode for item AD, Cylinder 1, 4 Heated Oxygen Sensor (rear).
9. Transaxle: 2nd speed
10. Drive with wide open throttle
11. Engine: 3,500 r/min
- The output voltages should be between 0.6 and 1.0 volt.
(4)Turn
the ignition switch to the "LOCK" (OFF) position.
Q. Is the sensor operating properly?
YES Go to Step 10.
NO Refer to DTC P0137 - Cylinder 1, 4 Heated Oxygen Sensor (rear) Circuit Low Voltage P0137, DTC P0138 - Cylinder 1, 4 Heated Oxygen Sensor
(rear) Circuit High Voltage P0138, DTC P0139 - Cylinder 1, 4 Heated Oxygen Sensor (rear) Circuit Slow Response P0139, DTC P0140 - Cylinder 1, 4 Heated Oxygen Sensor (rear) Circuit No Activity Detected P0140.
STEP 10. Using scan tool MB991958, check data list item AF: Cylinder 2, 3 Heated oxygen sensor (rear).
(1)Start the engine and run at idle.
(2)Set scan tool MB991958 to the data reading mode for item AF, Cylinder 2, 3 Heated Oxygen Sensor (rear).
12. Transaxle: 2nd speed
13. Drive with wide open throttle
14. 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 11.
NO Refer to DTC P0157 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit Low Voltage P0157, DTC P0158 - Cylinder 2, 3 Heated Oxygen Sensor
(rear) Circuit High Voltage P0158, DTC P0159 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit Slow Response P0159, DTC P0160 - Cylinder 2, 3 Heated Oxygen Sensor (rear) Circuit No Activity Detected P0160.
STEP 11. Check the EGR system.
Description and Operation.
Q. Is the EGR system normal?
YES Go to Step 12.
NO Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 12. Check the fuel pressure.
Refer to On-vehicle Service - Fuel Pressure Test Testing and Inspection.
Q. Is the fuel pressure normal?
YES Go to Step 13.
NO Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 13. Check the following items.
(1)Check the following items, and repair or replace the defective items.
15. Check the injectors for fuel leakage.
16. Check the ignition coil and spark plugs.
17. Check compression pressure.
18. Check the positive crankcase ventilation system.
19. Check the evaporative emission system.
(2)Then check the malfunction symptom.
Q. Is the malfunction symptom eliminated?
YES The check is completed.
NO Replace the catalytic converter. Then confirm that the malfunction symptom is eliminated.