P2DDF Fuel Injection Quantity D Higher Than Expected

P2DDF says injection path D sends more fuel than the engine control asked for. The estimate behind it depends heavily on the air side: if the airflow meter reports too little air, or the NOx or oxygen sensor shows a richer lambda than real, the module sees a surplus that the injectors never delivered, so sensors deserve a check before injectors are replaced. GM also weights its limits with ambient pressure, so altitude alone should not trip the test. Ford's diesels judge the global error over 15 percent rich as P0172, with coolant between 70 and 120 °C. No manufacturer documents P2DDF itself. Excess fuel in D means soot, smoke and, on diesels, faster filter loading; P2DDE is the shortfall.

Likely causes

Symptoms

• Check engine light on
• Black smoke, particulate filter loading faster
• Fuel consumption up

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com.