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DEF Contamination

2011-2012 Ford F-Super Duty vehicles equipped with a 6.7L diesel engine may exhibit DTC P1291 and/or P1292 due to an internally shorted fuel injector. An internal short in a fuel injector may be caused by the fuel being contaminated with diesel exhaust fluid (DEF) or by fuel gelling.

1. Remove the fuel conditioning module mounted filter.

2. Allow the filter and filter bowl to dry for two hours. If the filter and/or bowl turns white, the concern was caused by DEF contamination. The complete high pressure fuel system and diesel fuel control module (DFCM) will need to be replaced. The base fuel system will need to be flushed. If the filter did not turn white, proceed to Step 3.

3. Inspect the engine wiring harness (12B637) for wire chafes near the EGR cooler. If a chafe is found, repair as needed. Position the metal EGR cooler gasket tab eyelet rearward and flush with the cooler housing.

4. If no chafing is found, electrically disconnect each fuel injector for the suspect DTC P1291, at injectors 1, 4, 6 and 7. For DTC P1292, disconnect injectors 2, 3, 5 and 8.

5. Check for continuity between the injector electrical pins and the injector body. If continuity is present, replace the injectors and the injector return hose.

ITEM                                 P/N

Injector return hose………BC3Z-9A564-A

Fuel injectors 1, 2, 7, 8…..BC3Z-9H529-A

Fuel injectors 3, 4, 5, 6…..BC3Z-9H529-B

After allowing the fuel filter to dry, determine if it turns white.
<p>After allowing the fuel filter to dry, determine if it turns white.</p>

Inspect the wire chafing near the EGR cooler.
<p>Inspect the wire chafing near the EGR cooler.</p>

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