Troubleshooting

DTC P0175 SYSTEM TOO RICH (BANK 2)

CIRCUIT DESCRIPTION

DTC Detection Condition:

The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim includes short-term fuel trim and the long-term fuel trim.

The short-term fuel trim is the short-term fuel compensation used to maintain the air-fuel ratio at its ideal theoretical value. The signal from the heated oxygen sensor indicates whether the air-fuel ratio is RICH or LEAN compared to the ideal theoretical value, triggering a reduction in the fuel volume if the air-fuel ratio is rich, and an increase in the fuel volume if it is lean.

The long-term fuel trim is the overall fuel compensation carried out in long-term to compensate for a continual deviation of the short-term fuel trim from the central value, due to individual engine differences, wear overtime and changes in the using environment.

If both the short-term fuel trim and the long-term fuel trim are LEAN or RICH beyond a certain value, it is detected as a malfunction and the MIL (CHK ENG) lights up.

HINT: If the total of the short-term fuel trim value and the long-term fuel trim value is within -25 - 25 %, the system is functioning normally.

Wiring Diagram:

Step 1 - 3:

Step 4:

Step 5 - 7:

Step 8 - 9:

Step 10 - 12:

Step 13:

INSPECTION PROCEDURE:

HINT: Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

CONFIRMATION DRIVING PATTERN




a. Connect the hand-held tester to the DLC3.
b. Switch the hand-held tester from the "normal mode" to "check mode".
c. Start the engine and let the engine idle for 100 seconds or more.
d. Drive the vehicle at 40 km/h (24 mph) or more for 20 seconds or more.
e. Let the engine idle for 20 seconds or more.
f. Let the engine idle for 30 seconds.

HINT: If a malfunction exists, the MIL will light up during step (f).

NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will be impossible.
If you do not have the hand-held tester, turn the ignition switch OFF after performing steps (c) to (f), then perform steps (c) to (f) again.

CHECK FOR INTERMITTENT PROBLEMS

Hand-held tester only:
By putting the vehicle's ECM in the check mode, the 1 trip detection logic is possible instead of the 2 trip detection logic and the sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.

1. Clear the DTCs.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.