No Start Rough Idle – MIL with DTC’s P0171, P0174, P0173, P2195, P2197, P0420, P0301, P0302, P0303, P0304, P0305, P0306 – 2003-2005 Lincoln LS

ROUGH IDLE OR MIL LAMP ON

 

LINCOLN:

2003-2005 LS

 

2003-2005 Lincoln LS vehicles with 3.0L Duratec V6 engines may exhibit a no start, rough idle, or malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P0171, P0174, P0173, P2195, P2197, P0420, P0301, P0302, P0303, P0304, P0305, P0306.

 

This may be due to a vacuum leak at the PCV tube.

 

ACTION:

Inspect the PCV tube at all joints for possible disconnection and/or for loose or swollen rubber fittings.

If any of the connections/fittings are loose, install a new PCV tube.

Refer to the following Service Procedure.

If no problems are found with the PCV tube perform normal diagnostics outlined in the appropriate PC/ED manual.

 

SERVICE PROCEDURE

1. Remove engine appearance cover.
2. Disconnect the two (2) retention clips holding the throttle body coolant return line to the PCV hose.

NOTE: ONE RETENTION CLIP IS LOCATED AT RIGHT SIDE OF UPPER INTAKE MANIFOLD, AND THE SECOND CLIP IS BEHIND THE UPPER INTAKE MANIFOLD (FIGURE 1).

 

3. Remove the PCV hose push pin retainer from the flange at the right rear corner of upper intake manifold (Figure 1).

Figure 1

4. Disconnect PCV hose connector from the upper intake manifold at the rear of the throttle body (Figure 2).

Figure 2

5. Disconnect the PCV hose from the PCV valve elbow, at left rear of LH valve cover (Figure 3).

Figure 3

6. Remove and discard old PCV hose.

 

NOTE: THE NEW PCV HOSE COMES WITH SPRING CLAMPS ALREADY IN PLACE. DO NOT REMOVE THE PLASTIC CLIPS FROM THE SPRING CLAMPS PRIOR TO HOSE INSTALLATION. THE PLASTIC CLIPS HOLD THE SPRING CLAMPS OPEN.

NOTE: WHEN INSTALLING THE NEW PCV HOSE ASSEMBLY, THE FOLLOWING ORDER MUST BE FOLLOWED TO PREVENT DAMAGE TO THE NEW HOSE.

NOTE: THE NEW PCV HOSE SHOULD BE ROUTED SO THE COOLANT HOSE ON THE RIGHT SIDE OF THE UPPER INTAKE MANIFOLD, AND THE BRAKE BOOSTER VACUUM HOSE AT THE REAR LEFT SIDE OF THE UPPER INTAKE MANIFOLD, ARE POSITIONED UNDER THE NEW PCV HOSE (FIGURE 4).

Figure 4

7. Position new PCV hose by sliding it rearward over the intake manifold towards the cowl (Figure 5).

Figure 5

8. Attach and fully seat the PCV hose connector at intake manifold. Position the spring clamp 15 degrees inboard by rotating the hose. Do not attempt to rotate the spring clamp on the hose. While holding and fully seating the PCV hose on intake manifold hose nipple, remove the plastic clip from spring clamp by pulling the clip straight up (Figure 6).

Figure 6

9. Attach PCV hose to PCV valve elbow at the left rear of LH valve cover. While holding PCV hose in place on PCV elbow, remove the plastic clip from spring clamp by pulling clip straight up (Figure 7).

Figure 7

10. Attach PCV hose push pin to flange on right rear corner of the upper intake manifold (Figure 1).
11. Attach the two (2) coolant line retention clips to PCV hose. Position the coolant line rearward so that it does not contact the edge of the flange on the right rear corner of the upper intake manifold (Figure 1).
12. Reinstall engine cover.
13. Clear all DTCs.

 

PART NUMBER	PART NAME
3W4Z-6A664-CB	PCV Tube

 

Last update on 2026-06-10 / Affiliate links / Images from Amazon Product Advertising API

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Last update on 2026-06-18 / Affiliate links / Images from Amazon Product Advertising API

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Last update on 2026-06-10 / Affiliate links / Images from Amazon Product Advertising API

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