Hyundai Sonata LF: Intake And Exhaust System / Muffler Repair procedures
Front Muffler
| 1. |
Disconnect the battery negative terminal. |
| 2. |
Disconnect the rear oxygen sensor connector (A). 
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| 3. |
Remove the front muffler (A).
Tightening torque:
39.2 ~ 58.8 N.m (4.0 ~ 6.0 kgf.m, 28.9 ~ 43.4 lb-ft)
|

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| 4. |
Install in the reverse order of removal.
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When installing, replace with new gaskets. |
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Center Muffler
| 1. |
Remove the bracket(A). |
| 2. |
Remove the catalytic converter and the center muffler (B).
Tightening torque:
39.2 ~ 58.8 N.m (4.0 ~ 6.0 kgf.m, 28.9 ~ 43.4 lb-ft)
|

|
| 3. |
Install in the reverse order of removal.
|
When installing, replace with new gaskets. |
|
Main Muffler
| 1. |
Remove the catalytic converter and the center muffler (B).
Tightening torque:
39.2 ~ 58.8 N.m (4.0 ~ 6.0 kgf.m, 28.9 ~ 43.4 lb-ft)
|

|
| 2. |
Install in the reverse order of removal.
|
When installing, replace with new gaskets. |
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Replacement procedure of center muffler using clamp
Under warranty : Replace the center muffler assembly.
Out of warranty : It is available to replace the center muffler as the procedure below.
| 1. |
Check that the clamping part of the center muffler assembly is damaged or deformed.
If the muffler is too corroded to clamp, replace the center muffler assembly. 
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| 2. |
Record the gap (A, B, C, D, E, F) between the tail pipe (or tail trim) and the rear bumper.
[Pipe type] 
[Trim type] 
[Bumper-integrated trim type] 
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| 3. |
Remove the catalytic converter & center muffler (A). 
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| 4. |
Cut the center muffler as the instruction below.
[With dent]
| A. |
Cut the front dent of the muffler. 
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[Without dent]
| A. |
Cut the muffler by reffering to the front dent of A/S muffler as shown in the image below. 
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[A/S muffler]
| A. |
Cut the rear dent of the A/S muffler. 
|
| • |
To prevent a leak, remove the rust on the clamping part or the burr on the cutting part. |
| • |
Cut the pipe vertically. |
|
| • |
Pipe cutter available to cut the pipe vertically. |

| • |
Use a hacksaw as the procedure below, if a pipe cutter is unavailable. |
| 1. |
Mark the cutting position to cut the pipe vertically. 
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| 2. |
Cut the pipe along the marking line by using hacksaw. 
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| 5. |
Install the center muffler.
| (1) |
Install the catalytic converter (A) and the center muffler (B) for A/S by tightening the nuts lightly, not completely. 
|
When installing the muffler, replace the gasket with new one. |
|
| (2) |
Put the clamp (A) between the cutting part of each pipe and tighten the clamp lightly, not completely. 
|
| (3) |
Tighten the catalytic converter and the center muffler with specified torque.
Tightening torque :
39.2~58.8 N.m (4.0 ~ 6.0 kgf.m, 28.9~43.4 lb-ft)
|
|
| (4) |
Compare the gap between the tail pipe(or tail trim) and the
rear bumper with the record measured before removing the center muffler
assembly.
|
If the tail pipe is installed differently compared to the
initial position, the bumper might be damaged by the pipe heat or
interfere between the tail pipe and the rear bumper. |
|
| (5) |
Do not tighten the clamp at a time. Tighten the clamp nuts to the specified torque, by turns.
Tightening torque :
17.6~23.5 N.m (1.8 ~ 2.4 kgf.m, 13.0~17.4lb-ft)
|

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Do not reuse the clamp that was tightened completely. It may cause leak to reuse the clamp that was tightened completely. |
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Other information:
Inspection
Throttle Position Sensor (TPS)
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Start the engine and measure the output voltage of TPS 1 and 2 at C.T. and W.O.T.
Specification: Refer to “Specification”
ETC Motor
1...
C..