2020 GMC Sierra 3500HD P02D0 Code: Causes and Fixes
I have a 2020 GMC Sierra 3500HD with the 6.6L L5P Duramax and it set code P02D0. There are no other codes. The check engine light came on when I was accelerating hard to merge onto the highway, but the truck still drives normally—no noticeable loss of power, rough running, or other symptoms. I drove about 80 miles home with the light on and have continued driving it since without issues. Before taking it to a shop, I’m looking for common causes and any reasonable checks or fixes I can try first (I’ve seen possibilities mentioned like injector wiring/harness, the injector itself, or fuel system/injection pump-related issues).
Code P02D0 on your 2020 GMC Sierra 3500HD 6.6L L5P Duramax points to a problem with Fuel Injector #2 control circuit. The most likely cause is a wiring or connector issue at that injector, followed by a faulty injector itself. The fuel injection pump is less commonly the root cause but worth considering if the first two check out.
Most likely culprits
- Injector wiring harness or connector: Corrosion, broken wires, or poor connection at injector #2 is the most common cause of this code.
- Fuel Injector #2 failure: Internal short, open coil, or mechanical failure inside the injector can trigger this code.
- Fuel injection pump or control module: Less likely without other symptoms or codes, but a failing pump or module can cause injector control faults.
How to narrow it down
- Visually inspect injector #2 wiring and connector for corrosion, damage, or loose pins. Wiggle the harness while monitoring for changes in engine behavior or CEL.
- Measure injector #2 coil resistance with a multimeter. Compare to factory spec (usually around 1.5-2.5 ohms for Duramax injectors). Out-of-spec means injector likely bad.
- Check for voltage and ground at injector #2 connector with ignition on and engine cranking. No voltage or ground indicates wiring or PCM driver issue.
- Swap injector #2 with another cylinder's injector if possible and clear codes. If code moves to the other cylinder, injector is bad.
- Scan live data for injector pulse width and command signals to confirm PCM is commanding the injector properly.
- If wiring and injector test good, consider fuel injection pump diagnostics or PCM software updates at dealer.
Possible parts (if needed)
- Fuel Injector #2 (only if resistance or swap test confirms failure)
- Injector Wiring Harness or Connector (only if visual or electrical faults found)
- Fuel Injection Pump (only if injector and wiring check out but code persists)
A few questions
- Have you noticed any fuel smell, smoke, or rough running at any time?
- Has the truck had any recent work done on the fuel system or wiring harness?
- Do you have access to a scan tool that can show live injector pulse data or command status?