Tech Tip: Infiniti DTC P0505 Due To Incorrect Idle Speed – UnderhoodService
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Tech Tip: Infiniti DTC P0505 Due To Incorrect Idle Speed

If one of the applied vehicles above has a DTC P0505 AAC/V stored, with no customer driveability incident, it may be caused by an elevated or incorrect engine idle speed setting. In some of these cases, the Idle Air Volume Learning (IAVL) procedure should be performed to resolve the incident. Use the Service Procedure outlined in this Tech Tip to identify and address this incident.

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If one of the applied vehicles above has a DTC P0505 AAC/V stored, with no customer driveability incident, it may be caused by an elevated or incorrect engine idle speed setting. In some of these cases, the Idle Air Volume Learning (IAVL) procedure should be performed to resolve the incident.

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Use the Service Procedure outlined below to identify and address this incident.

Note: The IAVL procedure referenced here is a new procedure for the applied vehicles. Idle speed is now completely controlled by the applied vehicle’s ECM. The “base idle speed” adjustment is replaced by the IAVL procedure.

Service Procedure:

Note: If a DTC is found when checking the SELF-DIAG RESULTS, FREEZE FRAME DATA must be printed before the code is erased.

1. Using CONSULT-II, select ENGINE and SELF-DIAG RESULTS. Verify that DTC P0505 AAC/V is stored. Select PRINT and attach the printout to the work order for future reference.

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2. Select F.F. DATA, select PRINT and attach the printout to the work order for future reference.

MODEL       IDLE SPEED
2000 I30      M/T: 625 +/- 50 rpm, A/T: 700 +/-50
                     rpm (in P or N position)
2001 QX4    750 +/-50 rpm (A/T in P or N position)
2000 G20    800 +/-50 rpm (A/T in P or N position)
 

3. Does the freeze frame data printed in step 2 show an engine temperature above 158° F (70° C) and an idle speed near the target idle speed shown in the chart above?

– If yes, proceed to step 4.

– If not, refer to the EC section of the applicable service manual for diagnosis of DTC P0505, including circuit checks.

4. Start the engine, bring it to operating temperature, and then let it idle.

5. Press BACK on CONSULT II to back out of F.F. DATA and SELF-DIAG RESULTS.

Note: BACK may need to be selected more than once to get to the desired screen.

6. Select DATA MONITOR and SELECTIONS FROM MENU. Select the following items:

– Engine Speed

– IACV-AAC/V

– Ignition Timing

– Coolant Temp/s.

7. Press START to launch DATA MONITOR. Then, press COPY to print the items selected and attach the printout to the work order for future reference.

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8. Press BACK on CONSULT II to back out of DATA MONITOR, then select WORK SUPPORT and IDLE AIR VOL LEARN.

Note: BACK may need to be ­selected more than once to get to the desired screen.

9. Press START and wait for the procedure to complete (usually 20 seconds to one minute).

10. After the IDLE AIR VOL LEARN status shows CMPLT, press BACK on CONSULT II to back out of IDLE AIR VOL LEARN.

11. Select DATA MONITOR and SELECTIONS FROM MENU. ­Select the following items:

– Engine Speed

– IACV-AAC/V

– Ignition Timing

– Coolant Temp/s.

MODEL        IDLE SPEED                                          TIMING
2000 I30       M/T: 625 +/- 50 rpm,                               15° +/-2° BTDC
                     A/T: 700 +/-50 rpm (in P or N position)
2001 QX4    750 +/-50 rpm (A/T in P or N position)    15° +/-2° BTDC
2000 G20    800 +/-50 rpm (A/T in P or N position)     15° +/-2° BTDC

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12. Compare the current DATA MONITOR information with the results printed in step 7.

– The target idle speed and ignition timing should be within the specifications shown in the chart above.

– The AAC/V steps should ­reflect a change from the prior reading.

13. With the engine at operating temperature, test-drive the vehicle to verify the DTC does not reset and the idle speed remains stable.

Technical service bulletin courtesy of Mitchell 1.

For more information on Mitchell 1 products and services, automotive professionals can log onto the company’s website at www.mitchell1.com.

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