Fuel System - MIL ON, DTC P0420 Set
12-036
November 21, 2012
Applies To:
2007-09 RDX - ALL
2010 RDX 2WD - From VIN 5J8TB2H..AA000001 thru 5J8TB2H..AA004530
2010 RDX SH-AWD - From VIN 5J8TB1H..AA000001 thru 5J8TB1H..AA007495
MIL Comes On With DTC P0420
SYMPTOM
The MIL is on, and DTC P0420 (TWC catalyst system efficiency below threshold) is stored.
PROBABLE CAUSE
The flapper valve in the fuel tank unit may rub on the fuel filter. Under low fuel levels this may cause a lean fuel condition, which may result in
damage to the warm up three way catalyst (WU-TWC).
CORRECTIVE ACTION
Replace the fuel tank unit (fuel pump module assembly) and the WU-TWC.
PARTS INFORMATION
Fuel Pump Module Assembly (includes fuel tank unit, base gasket, locknut, and locknut plate):
P/N: 17045-STK-A01
Warm Up Three Way Catalyst:
P/N: 18190-RWC-A00
Turbo to Warm Up Three Way Catalyst Gasket:
P/N: 18234-RWC-A01
Turbo to Warm Up Three Way Catalyst Bolt:
(2 required)
P/N: 90011-RWC-A01
Turbo to Warm Up Three Way Catalyst Nut:
P/N: 90212-RSR-E01
Under-Floor Catalyst Front Gasket:
P/N: 18229-SLJ-033
Under-Floor Catalyst Rear Gasket:
P/N: 18393-SS0-J30
Exhaust Pipe to Under-Floor Catalyst Nut:
(3 required)
P/N: 90212-SA5-003
SH-AWD Only
Fill Washer, 24 mm:
P/N: 90441-PK4-000
Drain Washer, 18 mm:
P/N: 90471-PX4-000
REQUIRED MATERIALS
ATF-DW1 (SH-AWD Only):
(4 quarts)
P/N: 08200-9008A
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TOOL INFORMATION
Fuel Sender Wrench: T/N 07AAA-S0XA100
WARRANTY CLAIM INFORMATION
The normal warranty applies.
REPAIR PROCEDURE
1. Relieve the fuel pressure as described in the appropriate service manual. Online, enter keywords FUEL PRESSURE, and select Fuel Pressure
Relieving.
2. Remove the fuel cap.
3. Fold the rear seat down, then remove the left rear door sill trim.
4. Pull back the carpet to expose the fuel tank access panels.
5. Remove the access panel from the left side of the floor.
6. Disconnect the fuel tank unit 4P connector.
7. Disconnect the quick-connect fittings from the fuel tank unit.
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8. Loosen the locknut with a fuel sender wrench.
9. Remove the locknut and the locknut plate, and lift up the fuel tank unit from the fuel tank. Disconnect the transfer tube.
10. Temporarily position the new base gasket on the new fuel tank unit.
11. Make sure the mark on the transfer tube is facing up.
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12. Connect the transfer tube, then insert the new fuel tank unit partially into the fuel tank.
NOTE:
^ Be careful not to damage the new base gasket.
^ Be careful not to bend the fuel gauge sending unit.
^ Do not coat the base gasket with oil.
13. Transfer the base gasket from the fuel tank unit to the fuel tank.
14. Align the marks on the fuel tank and the fuel tank unit, then insert the fuel tank unit until it sits on the base gasket.
NOTE:
To prevent a fuel leak, check the base gasket, visually or by hand, to make sure it is not pinched.
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15. Using the fuel sender wrench, install a new locknut with a new locknut plate and torque it to 70 N.m (51.6 lb-ft).
NOTE:
^ After torquing, make sure the marks are still aligned.
^ After installation, check the base gasket visually or by hand again to make sure its not pinched.
16. Connect the fuel tank unit 4P connector.
17. Reconnect the negative cable to the battery and turn the ignition switch to ON (II) (do not operate the starter motor) two or three times to raise
the fuel pressure.
18. Check for leaks in the fuel supply system.
19. Reinstall the remaining parts in the reverse order of removal.
20. Remove the charge air cooler cover.
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21. Remove the charge air cooler cover bracket.
22. Remove the power steering feed hose bracket, then remove the hose in the direction of the arrow.
23. Remove the turbocharger cover.
24. Remove the A/F sensor.
25. Raise the vehicle on a lift.
26. Remove the splash shield.
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27. Remove the 4P connector from the water hose lower cover, then remove the cover.
28. Remove the under-floor TWC. NOTE: SH-AWD model is shown.
29. Remove the WU-TWC bracket. NOTE: SH-AWD model is shown.
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30. Disconnect the secondary HO2S 4P connector, then remove the secondary HO2S.
31. SH-AWD Models Only: Remove the transfer assembly.
^ Shift the transmission into N.
^ Remove the drain plug, and drain the automatic transmission fluid (ATF).
^ Reinstall the drain plug with a new sealing washer.
^ Remove the bolt securing the transfer breather hose bracket, and disconnect the breather hose from the breather pipe on the transfer
assembly. Cap the breather pipe to prevent fluid from leaking out.
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^ Make a reference mark across the propeller shaft and the transfer companion flange.
^ Separate the propeller shaft from the transfer companion flange.
^ Remove the transfer assembly from the transmission.
32. Remove the P/S heat shield.
33. Remove the water hose upper cover.
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34. Remove the mounting bolts and nut from the WU-TWC.
35. From under the vehicle, slide the WU-TWC toward the passenger's side to free the WU-TWC from the stud on the turbocharger.
36. Rotate the turbocharger side of the WU-TWC down to the steering gearbox housing, then slide the WU-TWC toward the driver's side along the
gearbox housing until the WU-TWC clears the turbocharger.
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37. Lower and rotate the under-floor TWC side of the WU-TWC toward the passenger's side, then remove the WU-TWC from the subframe.
38. Remove the WU-TWC cover.
39. Install the converter cover onto the new WU-TWC, then insert the WU-TWC into vehicle.
40. Install the parts in the reverse order of removal.
^ Replace the WU-TWC gaskets.
^ Replace the bolts and the nut that attach the WU-TWC to the turbocharger.
^ Replace the under-floor TWC gaskets and nuts.
41. SH-AWD Models: Refill the ATF - 2.9L (3.1 qt).
