P0171
ON BOARD DIAGNOSIS LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the front heated oxygen sensor. The ECM calculates the necessary compensation to correct the offset between the actual and the theoretical ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).
DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.
With Consult
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds .
3. Turn ignition switch "ON" and select "SELF-LEARN CONTROL" in "ACTIVE TEST" mode with CONSULT-II.
4. Clear the self-learning control coefficient by touching "CLEAR".
5. Select "DATA MONITOR" mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 should be detected at this stage, if a malfunction exists.
7. If it is difficult to start engine at step 6, the fuel injection system has a malfunction.
8. Crank engine while depressing accelerator pedal. If 1st trip DTC is detected and engine starts, go to "Diagnostic Procedure" below. If engine does not start, visually check for exhaust and intake air leak.
OR
With Generic Scan Tools
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds .
3. Disconnect mass air flow sensor harness connector. Then restart and run engine for at least 3 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness connector.
5. Select "MODE 7" with GST Make sure 1st trip DTC P0100 is detected.
6. Select "MODE 4" with GST and erase the 1st trip DTC P0100.
7. Start engine again and run it for at least 10 minutes at idle speed.
8. Select "MODE 7" with GST. The 1st trip DTC P0171 should be detected at this stage, if a malfunction exists.
9. If it is difficult to start engine at step 8, the fuel injection system has a malfunction.
10. Crank engine while depressing accelerator pedal. If engine starts, go to "Diagnostic Procedure" below. If 1st trip DTC is detected and engine does not start, visually check for exhaust and intake air leak.
OR
Without Consult
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds .
3. Disconnect mass air flow sensor harness connector. Then restart and run engine for at least 3 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness connector.
5. Turn ignition switch "ON".
6. Perform Diagnostic Test Mode II (Self-diagnostic results) with ECM. Make sure 1st trip DTC 0102 is detected.
7. Erase the 1st trip DTC 0102 by changing from Diagnostic Test Mode II to Diagnostic Test Mode I.
8. Perform Diagnostic Test Mode II (Self-diagnostic results) with ECM. Make sure DTC 0505 is detected.
9. Start engine again and run it for at least 10 minutes at idle speed.
The 1st trip DTC 0115 should be detected at this stage, if a malfunction exists.
10. If it is difficult to start engine at step 9, the fuel injection system also has a malfunction.
11. Crank engine while depressing accelerator pedal. If 1st trip DTC is detected and engine starts, go to "Diagnostic Procedure" below. If engine does not start, visually check for exhaust and intake air leak.
EC-FUEL-01:
EC-FUEL-01 - Connector View:
WIRING DIAGRAM
DIAGNOSTIC PROCEDURE
Diagnostic Procedure (Part 1 Of 2):
