P2DDE Fuel Injection Quantity D Lower Than Expected

P2DDE covers a fourth injection path, D, delivering too little fuel. The letter is assigned by the manufacturer; no one documents this code openly. CARB section 1968.2 (f)(4.2.2) sets two ways to catch it: either the shortfall is detected before emissions pass the malfunction threshold, or, where no injection fault can push emissions that high, once the control has used up its range and the commanded quantity cannot be reached. Since 2013 the monitor must also count how often it runs. Ford's diesels turn the global version of this finding into a lean code, P0171, below a fueling error of -0.15. Look first at the injectors of group D, then at fuel supply and the air and lambda signals. P2DDF is too much in D.

Likely causes

Symptoms

• Check engine light on
• Lack of power
• Occasional stumbling or misfire-like running

Repair estimate

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

Parts involved

Related codes

References: law.cornell.edu, fordservicecontent.com.