Scheme 1
DTC P0401: EGR Insufficient Flow
Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
- Turn the ignition switch ON (II).
- Clear the DTC with the HDS.
- Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Do the EGR TEST in the INSPECTION MENU with the HDS. Is the result OK? YES - Go to step 5. NO - Go to step 7 .
- Test-drive under these conditions: Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C) Transmission in D position Vehicle speed at 25 mph (40 km/h) or more, and engine speed between 1,100 rpm and 3,000 rpm During the drive, decelerate (with the throttle fully closed) for 5 seconds
- Monitor the OBD STATUS for DTC P0401 in the DTCs MENU with the HDS. Does the screen indicate FAILED? YES - Remove the engine cover, clean the intake manifold, and EGR ports with throttle plate and induction cleaner, then go to step 9 . NO - If the screen indicates PASSED, intermittent failure, the system is OK at this time. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 5 and recheck.
- Turn the ignition switch OFF.
- Replace the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
- Test-drive under these conditions: Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C) Transmission in D position Vehicle speed at 25 mph (40 km/h) or more, and engine speed between 1,100 rpm and 3,000 rpm During the drive, decelerate (with the throttle fully closed) for 5 seconds
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P0401 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 15 . NO - Go to step 14.
- Monitor the OBD STATUS for DTC P0401 in the DTCs MENU with the HDS. Does the screen indicate PASSED? YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 13 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1 . If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 12 .
- Reconnect all connectors, then update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
- Test-drive under these conditions: Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C) Transmission in D position Vehicle speed at 25 mph (40 km/h) or more, and engine speed between 1,100 rpm and 3,000 rpm During the drive, decelerate (with the throttle fully closed) for 5 seconds
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P0401 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then go to step 16 . If the PCM was substituted, go to step 1 . NO - Go to step 18.
- Monitor the OBD STATUS for DTC P0401 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 «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs were indicated in step 17 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then go to step 16 . If the PCM was substituted, go to step 1 . If the screen indicates NOT COMPLETED, go to step 16 .
DTC P0404: EGR Control Circuit Range/ Performance Problem
Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
Scheme 2
Scheme 3
Scheme 4
Scheme 5
Scheme 6
- Turn the ignition switch ON (II).
- Clear the DTC with the HDS.
- Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Do the EGR TEST in the INSPECTION MENU with the HDS. Is the result OK? YES - Intermittent failure, the system is OK at this time. Clean any carbon build-up on the EGR valve with throttle plate and induction cleaner. NO - Go to step 5.
- Turn the ignition switch OFF.
- Disconnect the EGR valve 6P connector.
- At the sensor side, measure resistance between EGR valve 6P connector terminals No. 1 and No. 2. Is there 100 kohms, or more? YES - Go to step 25 . NO - Go to step 8.
- Measure resistance between EGR valve 6P connector terminals No. 1 and No. 3. Is there 100 kohms, or more? YES - Go to step 25 . NO - Go to step 9.
- Check for continuity between EGR valve 6P connector terminal No. 6 and body ground. Is there continuity? YES - Go to step 10. NO - Repair open in the wire between the EGR valve and G101, then go to step 26 .
- Jump the SCS line with the HDS.
- Disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C10 and body ground. Is there continuity? YES -Repair short in the wire between the PCM (C10) and the EGR valve, then go to step 26 . NO - Go to step 13.
- Check for continuity between PCM connector terminal C10 and EGR valve 6P connector terminal No. 4. Is there continuity? YES - Go to step 14. NO - Repair open in the wire between the PCM (C10) and the EGR valve, then go to step 26 .
- Remove the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Clean the intake manifold EGR port and the passage inside the EGR valve with throttle plate and induction cleaner.
- Install the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Reconnect the EGR valve 6P connector.
- Reconnect PCM connector C (49P).
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
- Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Do the EGR TEST in the INSPECTION MENU with the HDS. Is the result OK? YES - Go to step 32 . NO - Go to step 24.
- Turn the ignition switch OFF.
- Replace the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Reconnect all connectors.
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
- Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Do the EGR TEST in the INSPECTION MENU with the HDS.
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P0404 indicated? YES -Check for poor connections or loose terminals at the EGR valve and the PCM. If the connector and terminal fits are OK, go to step 34 . NO -Go to step 33.
- Monitor the OBD STATUS for DTC P0404 in the DTCs MENU with the HDS. Does the screen indicate PASSED? YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 32 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1 . If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to step 30 .
- Reconnect all connectors, then update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
- Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Do the EGR TEST in the INSPECTION MENU with the HDS.
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P0404 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then go to step 35 . If the PCM was substituted, go to step 1 . NO - Go to step 38.
- Monitor the OBD STATUS for DTC P0404 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 «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs were indicated in step 37 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then go to step 35 . If the PCM was substituted, go to step 1 . If the screen indicates NOT COMPLETED, go to step 35 .
DTC P0406: EGR Valve Position Sensor Circuit High Voltage
Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
Scheme 7
Scheme 8
- Turn the ignition switch ON (II).
- Check the EGR VLS in the DATA LIST with the HDS. Is 4.88 V or more indicated? YES - Go to step 3. NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EGR valve and the PCM.
- Turn the ignition switch OFF.
- Disconnect the EGR valve 6P connector.
- Turn the ignition switch ON (II).
- Measure voltage between EGR valve 6P connector terminals No. 2 and No. 3. Is there about 5 V? YES - Go to step 11 . NO - Go to step 7.
- Turn the ignition switch OFF.
- Jump the SCS line with the HDS.
- Disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C16 and EGR valve 6P connector terminal No. 2. Is there continuity? YES - Go to step 18 . NO - Repair open in the wire between the EGR valve and the PCM (C16), then go to step 13 .
- Turn the ignition switch OFF.
- Replace the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Reconnect all connectors.
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P0406 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1 . NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) .
- Reconnect all connectors.
- Update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P0406 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM (see «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs are indicated, go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) .
Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
Scheme 9
Scheme 10
Scheme 11
Scheme 12
Scheme 13
Scheme 14
Scheme 15
Scheme 16
Scheme 17
Scheme 18
- Turn the ignition switch ON (II).
- Clear the DTC with the HDS.
- Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Do the EGR 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 EGR valve and the PCM. NO - Go to step 5.
- Turn the ignition switch OFF.
- Turn the ignition switch ON (II).
- Check the EGR VLS in the DATA LIST with the HDS. Is about 0 V indicated? YES - Go to step 8. NO - Go to step 21 .
- Turn the ignition switch OFF.
- Disconnect the EGR valve 6P connector.
- Turn the ignition switch ON (II).
- Measure voltage between EGR valve 6P connector terminal No. 3 and body ground. Is there about 5 V? YES - Go to step 16 . NO - Go to step 12.
- Turn the ignition switch OFF.
- Jump the SCS line with the HDS.
- Disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C12 and EGR valve 6P connector terminal No. 3. Is there continuity? YES - Go to step 52 . NO - Repair open in the wire between the EGR valve and the PCM (C12), then go to step 44 .
- Turn the ignition switch OFF.
- Jump the SCS line with the HDS.
- Disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C34 and body ground. Is there continuity? YES - Repair short in the wire between the PCM (C34) and the EGR valve, then go to step 44 . NO - Go to step 20.
- Check for continuity between PCM connector terminal C34 and EGR valve 6P connector terminal No. 1. Is there continuity? YES - Go to step 21. NO - Repair open in the wire between the PCM (C34) and the EGR valve, then go to step 44 .
- Turn the ignition switch OFF.
- If not already done, disconnect the EGR valve 6P connector.
- At the EGR valve side, measure resistance between EGR valve 6P connector terminals No. 1 and No. 2. Is there resistance of 100 kohms or more? YES - Go to step 43 . NO - Go to step 24.
- At the EGR valve side, measure resistance between EGR valve 6P connector terminals No. 1 and No. 3. Is there resistance of 100 kohms or more? YES - Go to step 43 . NO - Go to step 25.
- If not already done, jump the SCS line with the HDS.
- If not already done, disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C10 and body ground. Is there continuity? YES - Repair short in the wire between the PCM (C10) and the EGR valve, then go to step 44 . NO - Go to step 28.
- Check for continuity between PCM connector terminal C10 and EGR valve 6P connector terminal No. 4. Is there continuity? YES - Go to step 29. NO - Repair open in the wire between the PCM (C10) and the EGR valve, then go to step 44 .
- Check for continuity between EGR valve 6P connector terminal No. 6 and body ground. Is there continuity? YES - Go to step 30. NO - Repair open in the wire between the EGR valve and G101 (see «GROUND TO COMPONENTS INDEX»(/acura/mdx/ii-2006-2010/remont/body-electrical/#ground-distribution__ground-to-components-index) ), then go to step 44 .
- Reconnect PCM connector C (49P).
- At the EGR valve side, connect the battery positive terminal to EGR valve 6P connector terminal No. 4 with a jumper wire.
- Start the engine and let it idle, then connect the battery negative terminal to EGR valve 6P connector terminal No. 6 with a jumper wire. Does the engine stall or run rough? YES - Go to step 51 . NO - Go to step 33.
- Turn the ignition switch OFF.
- Remove the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Clean the intake manifold EGR port at the passage inside the EGR valve with throttle plate and induction cleaner.
- Install the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Reconnect all connectors.
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
- Do the EGR TEST in the INSPECTION MENU with the HDS. Is the result OK? YES - Go to step 49 . NO - Go to step 42.
- Turn the ignition switch OFF.
- Replace the EGR valve (see «EGR VALVE REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) ).
- Reconnect all connectors.
- Turn the ignition switch ON (II).
- Reset the PCM with the HDS.
- Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/mdx/ii-2006-2010/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
- Do the EGR TEST in the INSPECTION MENU with the HDS.
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P2413 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1 . NO - Go to step 50.
- Monitor the OBD STATUS for DTC P2413 in the DTCs MENU with the HDS. Does the screen indicate PASSED? YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 49 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1 . If the screen indicates EXECUTING or OUT OF CONDITION, keep idling until a result comes on.
- Turn the ignition switch OFF.
- Reconnect all connectors.
- Update the PCM if it does not have the latest software (see «PCM UPDATE»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-update) ), or substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ).
- Do the EGR TEST in the INSPECTION MENU with the HDS.
- Check for Temporary DTCs or DTCs with the HDS. Is DTC P2413 indicated? YES - Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then recheck. If the PCM was substituted, go to step 1 . NO - Go to step 56.
- Monitor the OBD STATUS for DTC P2413 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 «PCM REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#pgm-fi-system__pcm-replacement) ). If any other Temporary DTCs or DTCs were indicated in step 55 , go to the indicated «DTCs troubleshooting»(/acura/mdx/ii-2006-2010/remont/auxiliary-emission-control-systems/#egr-system) . NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM (see «SUBSTITUTING THE PCM»(/acura/mdx/ii-2006-2010/remont/testing-diagnostics/#fuel-and-emissions-systems__substituting-the-pcm) ), then go to step 54 . If the PCM was substituted, go to step 1 . If the screen indicates EXECUTING or OUT OF CONDITION, go to step 54 and recheck.
Scheme 19
- Remove the engine cover (see step 1 on «INTAKE MANIFOLD REMOVAL AND INSTALLATION»(/acura/mdx/ii-2006-2010/remont/exhaust/#intake-manifold-and-exhaust-system) ).
- Remove the main under-hood fuse box.
- Disconnect the EGR valve connector (A).
- Remove the EGR valve (B).
- Install the parts in the reverse order of removal with a new gasket (C).