Intake Air System Acura TL IV

Scheme 1

DTC P1077: IMT Valve Stuck in High RPM Position

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION )

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1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
2. Clear the DTC with the HDS
3. Do the IMT TEST in the INSPECTION MENU with the HDS Is the result OK? YES -Intermittent failure, the system is OK at this time Check for poor connections or loose terminals at the IMT actuator and the PCM NO -Go to step 4
4. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
5. Disconnect the IM T actuator 5P connector
6. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
7. Measure the voltage between IMT actuator 5P connector terminal No 1 and body ground Is there about 5 V? YES -Go to step 12 NO -Go to step 8
8. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
9. Jump the SCS line with the HDS
10. Disconnect PCM connector C (49P)
11. Check for continuity between IMT actuator 5P connector terminal No 1 and PCM connector terminal C11 Is there continuity? YES -Go to step 36 NO -Repair open in the wire between the PCM (C11) and the IMT actuator, then go to step 30
12. Measure the voltage between IMT actuator 5P connector terminal No 3 and body ground Is there about 5 V? YES -Go to step 17 NO -Go to step 13
13. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
14. Jump the SCS line with the HDS
15. Disconnect PCM connector B (49P)
16. Check for continuity between IMT actuator 5P connector terminal No 3 and PCM connector terminal B19 Is there continuity? YES -Go to step 36 NO -Repair open in the wire between the PCM (B19) and the IMT actuator, then go to step 30
17. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
18. Jump the SCS line with the HDS
19. Disconnect PCM connector C (49P)
20. Check for continuity between IMT actuator 5P connector terminal No 2 and PCM connector terminal C16 Is there continuity? YES -Go to step 21 NO -Repair open in the wire between the PCM (C16) and the IMT actuator, then go to step 30
21. Check for continuity between PCM connector terminal C48 and body ground Is there continuity? YES -Repair short in the wire between the PCM (C48) and the IMT actuator, then go to step 30 NO -Go to step 22
22. Check for continuity between PCM connector terminal C49 and body ground Is there continuity? YES -Repair short in the wire between the PCM (C49) and the IMT actuator, then go to step 30 NO -Go to step 23
23. Check for continuity between IMT actuator 5P connector terminal No 5 and PCM connector terminal C48 Is there continuity? YES -Go to step 24 NO -Repair open in the wire between the PCM (C48) and the IMT actuator, then go to step 30
24. Check for continuity between IMT actuator 5P connector terminal No 4 and PCM connector terminal C49 Is there continuity? YES -Go to step 25 NO -Repair open in the wire between the PCM (C49) and the IMT actuator, then go to step 30
25. Remove the IMT actuator (see «IMT ACTUATOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) )
26. Move the IMT valve by hand Does it move smoothly? YES -Go to step 27 NO -Remove the intake manifold upper cover (see step 5 on «INSTALLATION»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system) ), and repair the stuck valve If needed, replace the intake manifold (see «REMOVAL»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system) ), then go to step 30
27. Substitute a known-good IMT actuator (see «IMT ACTUATOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) )
28. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
29. Do the IMT TEST in the INSPECTION MENU with the HDS Is the result OK? YES -Replace the original IMT actuator (see «IMT ACTUATOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) ), then go to step 30 NO -Go to step 36
30. Reconnect all connectors
31. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
32. Reset the PCM with the HDS
33. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#idle-control-system__pcm-idle-learn-procedure) )
34. Check for Pending or Confirmed DTCs with the HDS Is DTC P1077 indicated? YES -Check for poor connections or loose terminals at the IMT actuator and the PCM, then go to step 1 NO -Go to step 35
35. Monitor the OBD STATUS for DTC P1077 in the DTCs MENU with the HDS Does the screen indicate PASSED? YES -Troubleshooting is complete If any other Pending or Confirmed DTCs were indicated in step 34, go to the indicated DTC's troubleshooting NO -If the screen indicates FAILED, check for poor connections or loose terminals at the IMT actuator and the PCM, then go to step 1 If the screen indicates NOT COMPLETED, keep idling until a result comes on
36. Reconnect all connectors
37. Update the PCM if it does not have the latest software (see «ECM/PCM UPDATE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__ecmpcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE ECM/PCM»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__substituting-the-ecmpcm) )
38. Start the engine, and let it idle without load (A/T in P or N, M/T in neutral) until the radiator fan comes on
39. Check for Pending or Confirmed DTCs with the HDS Is DTC P1077 indicated? YES -Check for poor connections or loose terminals at the IMT actuator and the PCM If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE ECM/PCM»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__substituting-the-ecmpcm) ), then go to step 38 If the PCM was substituted, go to step 1 NO -Go to step 40
40. Monitor the OBD STATUS for DTC P1077 in the DTCs MENU with the HDS Does the screen indicates PASSED? YES -If the PCM was updated, troubleshooting is complete If the PCM was substituted, replace the original PCM (see «ECM/PCM REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__ecmpcm-replacement) ) If any other Pending or Confirmed DTCs were indicated in step 39, go to the indicated DTC's troubleshooting NO -If the screen indicated FAILED, check for poor connections or loose terminals at the IMT actuator and the PCM If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE ECM/PCM»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__substituting-the-ecmpcm) ), then go to step 38 If the PCM was substituted, go to step 1 If the screen indicates NOT COMPLETED, keep idling until a result comes on

DTC P1078: IMT Valve Stuck in Low RPM Position

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION )

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1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
2. Clear the DTC with the HDS
3. Do the IMT TEST in the INSPECTION MENU with the HDS Is the result OK? YES -Intermittent failure, the system is OK at this time Check for poor connections or loose terminals at the IMT actuator and the PCM NO -Go to step 4
4. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
5. Disconnect the IMF actuator 5P connector
6. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
7. Check the IMT VALVE SW in the DATA LIST with the HDS Is CLOSE indicated? YES -Go to step 12 NO -Go to step 8
8. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
9. Jump the SCS line with the HDS
10. Disconnect PCM connector B (49P)
11. Check for continuity between PCM connector terminal B19 and body ground Is there continuity? YES -Repair short in the wire between the PCM (B19) and the IMT actuator, then go to step 24 NO -Go to step 31
12. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
13. Jump the SCS line with the HDS
14. Disconnect PCM connector C(49P)
15. Check for continuity between PCM connector terminal C48 and body ground Is there continuity? YES -Repair short in the wire between the PCM (C48) and the IMT actuator, then go to step 24 NO -Go to step 16
16. Check for continuity between PCM connector terminal C49 and body ground Is there continuity? YES -Repair short in the wire between the PCM (C49) and the IMT actuator, then go to step 24 NO -Go to step 17
17. Check for continuity between IMT actuator 5P connector terminal No 5 and PCM connector terminal C48 Is there continuity? YES -Go to step 18 NO -Repair open in the wire between the PCM (C48) and the IMT actuator, then go to step 24
18. Check for continuity between IMT actuator 5P connector terminal No 4 and PCM connector terminal C49 Is there continuity? YES -Go to step 19 NO -Repair open in the wire between the PCM (C49) and the IMT actuator, then go to step 24
19. Remove the IMT actuator (see «IMT ACTUATOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) )
20. Move the IMT valve by hand Does it move smoothly? YES -Go to step 21 NO -Remove the intake manifold upper cover (see step 5 on «INSTALLATION»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system) ), and repair the stuck valve If needed, replace the intake manifold (see «REMOVAL»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system) ), then go to step 24
21. Substitute a known-good IMT actuator (see «IMT ACTUATOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) )
22. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
23. Do the IMT TEST in the INSPECTION MENU with the HDS Is the result OK? YES -Replace the original IMT actuator (see «IMT ACTUATOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) ), then go to step 24 NO -Go to step 32
24. Reconnect all connectors
25. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
26. Reset the PCM with the HDS
27. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#idle-control-system__pcm-idle-learn-procedure) )
28. Start the engine, and let it idle without load (A/T in P or N, M/T in neutral) until the radiator fan comes on
29. Hold the engine speed at 4,000 rpm for 3 seconds or more, then let it idle
30. Check for Pending or Confirmed DTCs with the HDS Is DTC P1078 indicated? YES -Check for poor connections or loose terminals at the IMT actuator and the PCM, then go to step 1 NO -Go to step 31
31. Monitor the OBD STATUS for DTC P1078 in the DTCs MENU with the HDS Does the screen indicates PASSED? YES -Troubleshooting is complete If any other Pending or Confirmed DTCs were indicated in step 30, go to the indicated DTC's troubleshooting NO -If the screen indicates FAILED, check for poor connections or loose terminals at the IMT actuator and the PCM, then go to step 1 If the screen indicates NOT COMPLETED, go to step 28
32. Reconnect all connectors
33. Update the PCM if it does not have the latest software (see «ECM/PCM UPDATE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__ecmpcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE ECM/PCM»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__substituting-the-ecmpcm) )
34. Start the engine, and let it idle without load (A/T in P or N, M/T in neutral) until the radiator fan comes on
35. Hold the engine speed at 4,000 rpm for 3 seconds or more, then let it idle
36. Check for Pending or Confirmed DTCs with the HDS Is DTC P1078 indicated? YES -Check for poor connections or loose terminals at the IMT actuator and the PCM If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE ECM/PCM»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__substituting-the-ecmpcm) ), then go to step 34 If the PCM was substituted, go to step 1 NO -Go to step 37
37. Monitor the OBD STATUS for DTC P1078 in the DTCs MENU with the HDS Does the screen indicate PASSED? YES -If the PCM was updated, troubleshooting is complete If the PCM was substituted, replace the original PCM (see «ECM/PCM REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__ecmpcm-replacement) ) If any other Pending or Confirmed DTCs were indicated in step 36, go to the indicated DTC's troubleshooting NO -If the screen indicated FAILED, check for poor connections or loose terminals at the IMT actuator and the PCM If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE ECM/PCM»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__substituting-the-ecmpcm) ), then go to step 34 If the PCM was substituted, go to step 1 If the screen indicates NOT COMPLETED, go to step 34

Carbon Accumulation Check

Note. If the malfunction indicator lamp (MIL) has been reported on, check for diagnostic trouble codes (DTCs)

Scheme 16

1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard
2. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
3. Make sure the HDS communicates with the PCM If it does not, go to the DLC circuit troubleshooting (see «DLC CIRCUIT TROUBLESHOOTING»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__dlc-circuit-troubleshooting) )
4. Start the engine Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle
5. Check the REL TP SENSOR in the DATA LIST with the HDS The reading should be below 2 46 percent If it is not, clean the throttle body (see «THROTTLE BODY CLEANING»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system__throttle-body-cleaning) )

Throttle Position Learning Check

Note. If the malfunction indicator lamp (MIL) has been reported on, check for diagnostic trouble codes (DTCs)

Scheme 17

1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard
2. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
3. Make sure the HDS communicates with the PCM If it does not, go to the DLC circuit troubleshooting (see «DLC CIRCUIT TROUBLESHOOTING»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__dlc-circuit-troubleshooting) )
4. Select the INSPECTION MENU with the HDS
5. Do the TP LEARNING CHECK in the ETCS TEST If needed, clean the throttle body (see «THROTTLE BODY CLEANING»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system__throttle-body-cleaning) )

Throttle Body Cleaning

Scheme 18

1. Check for damage to the air cleaner element If the air cleaner element is damaged, replace it (see «AIR CLEANER ELEMENT INSPECTION/REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system) )
2. Remove the throttle body (see «THROTTLE BODY REMOVAL/INSTALLATION»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system__throttle-body-removalinstallation) )
3. Clean off the carbon from the throttle valve and inside the throttle body with a paper towel soaked in throttle plate cleaner NOTE: Remove the throttle body to clean it Be careful not to pinch your fingers To avoid removing the molybdenum coating, do not clean the bearing area of the throttle shaft (A) Do not spray throttle plate cleaner directly on the throttle body Use Acura genuine throttle plate cleaner
4. Install the throttle body (see «THROTTLE BODY REMOVAL/INSTALLATION»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system__throttle-body-removalinstallation) )
5. Reset the PCM with the HDS (see «ECM/PCM RESET»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#fuel-and-emissions-systems__ecmpcm-reset) )
6. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode and wait 2 seconds
7. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#idle-control-system__pcm-idle-learn-procedure) )

Scheme 19

1. Do the battery removal procedure (see «BATTERY REMOVAL AND INSTALLATION»(/acura/tl/iv-2008-2011/remont/body-electrical/#battery) )
2. Disconnect the MAF sensor/IAT sensor 5P connector (A)
3. Remove the harness clamps (B) and the bolt (C)
4. Loosen the band (D), then remove the air cleaner housing (E)
5. Install the parts in the reverse order of removal NOTE: When tightening the screw of the hose band (F), align the edge of the hose band (G) between the marks (H) (or within the mark (I)) painted on the hose band
6. Do the battery installation procedure (see «BATTERY REMOVAL AND INSTALLATION»(/acura/tl/iv-2008-2011/remont/body-electrical/#battery) )

Scheme 20

1. Open the air cleaner housing cover (A)
2. Remove the air cleaner element (B) from the air cleaner housing (C)
3. Check the air cleaner element for damage or clogging If it is damaged or clogged, replace it NOTE: Do not use compressed air to clean the air cleaner element
4. Clean and remove any debris from inside the air cleaner housing
5. Install the parts in the reverse order of removal If you did not replace the air cleaner element, this procedure is complete If the maintenance minder required air cleaner element replacement, reset the maintenance minder (see «MAINTENANCE MAIN ITEMS»(/acura/tl/iv-2008-2011/remont/reset-procedures/#maintenance) ) If the idle speed fluctuates, do the idle speed inspection (see «IDLE SPEED INSPECTION»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#idle-control-system__idle-speed-inspection) )

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1. Remove the splash separator (A)
2. Do the battery removal procedure (see «BATTERY REMOVAL AND INSTALLATION»(/acura/tl/iv-2008-2011/remont/body-electrical/#battery) )
3. Remove the air cleaner (see «THROTTLE BODY CLEANING»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#intake-air-system__throttle-body-cleaning) )
4. Remove the battery base (A)
5. Remove the intake air duct (A)
6. Remove the front bumper (see «FRONT BUMPER REMOVAL/INSTALLATION»(/acura/tl/iv-2008-2011/remont/exterior-body-panels/#bumper-system__front-bumper-removalinstallation) )
7. Remove the intake air resonator (A)
8. J37A4 engine: Remove the brake duct (B).
9. Install the parts in the reverse order of removal
10. Do the battery installation procedure (see «BATTERY REMOVAL AND INSTALLATION»(/acura/tl/iv-2008-2011/remont/body-electrical/#battery) )

Scheme 25

1. Disconnect the IMT actuator 5P connector (A)
2. Remove the bolts (B) and the IMT actuator (C)
3. Install the parts in the reverse order of removal with a new O-ring (D)

Throttle Body Removal/Installation

Note. If you are replacing or cleaning the throttle body, begin at step 1 If you are removing the throttle body temporarily, begin at step 4

Scheme 26

1. Connect the HDS while the engine is stopped
2. Select the INSPECTION MENU with the HDS
3. Do the TP POSITION CHECK in the ETCS TEST
4. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode
5. Disconnect the MAP sensor connector (A)
6. Remove the intake air duct (B)
7. Disconnect the throttle body connector (C)
8. Disconnect and plug the water bypass hoses (D), then remove the throttle body (E)
9. Install the parts in the reverse order of removal with a new gasket (F) NOTE: When tightening the screw of the hose band (G), align the edge of the hose band (H) with the mark (I) painted on the hose band After the installation, refill the radiator with engine coolant (see «COOLANT CHECK»(/acura/tl/iv-2008-2011/remont/cooling-system-mechanical/#cooling-system) )
10. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#idle-control-system__pcm-idle-learn-procedure) )

See also:
• GENERAL TROUBLESHOOTING INFORMATION
• INSTALLATION
• PCM IDLE LEARN PROCEDURE
• ECM/PCM UPDATE
• SUBSTITUTING THE ECM/PCM
• ECM/PCM REPLACEMENT
• DLC CIRCUIT TROUBLESHOOTING
• ECM/PCM RESET
• BATTERY REMOVAL AND INSTALLATION
• MAINTENANCE MAIN ITEMS
• IDLE SPEED INSPECTION
• FRONT BUMPER REMOVAL/INSTALLATION
• COOLANT CHECK
• IMT ACTUATOR REPLACEMENT
• THROTTLE BODY CLEANING
• THROTTLE BODY REMOVAL/INSTALLATION