P020A: Cylinder 1 Injection Timing

What does P020A mean?

P020A reports a fault in the injection timing of cylinder 1 on a diesel engine. Unlike P01CB/P01CC ('over retarded/advanced', the result of the injector learning routine in overrun), this code has no direction, and what it checks is up to the manufacturer. GM uses it as an electrical check on a four-cylinder diesel and on the 6.6 litre L5P Duramax V8: at every injection the engine module measures how long the injector current takes to reach its pull-in level of 13 A. If on the V8 that time is outside 60–150 µs in 10 of 20 samples, the code sets and the warning light comes on in the first trip. FCA lists it for the 3.0 litre EcoDiesel V6 together with the learning codes: check injector coding, charge air leaks and the injector clamp, reset the zero fuel calibration and repeat the learning drive; if the code returns, the injector is replaced.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Rough running or misfire, rough idle
• Loss of power, smoke or knocking possible

Common causes

• High Injector of cylinder 1 faulty (coil, armature, wear, deposits)
• Medium Injector wiring or connector: contact resistance, corrosion, chafing
• Medium Engine software sets the code falsely (update available for some models)
• Low Injector driver stage or boost voltage in the engine module
• Low Wrong injector code, contaminated fuel or loose injector clamp

Likelihood is a general estimate across vehicles; your make and model may differ.