P2147: Fuel Injector Group A Supply Voltage Circuit Low

What does P2147 mean?

P2147 means the common feed of injector group A is pulled toward ground. GM documents it in detail for its 2018 Duramax diesels: the high-side line to injectors 1 and 4 (group 1 on both the 2.8 L four and the 6.6 L V8) shows 0.5 Ω or less to ground while the driver is switched on; with the engine running and more than 11 V, 5 failures in 10 samples at 100 ms set it, type A, lamp on the first trip (2025 tables: 4 of 8). Ford's 2023 diesels report a short of group A to ground or battery found by the driver chip after about 0.2 s. On GM petrol direct injection such as the Saab 9-5 2.0T the code stands for low voltage on the high-side control line of cylinder 1. Both injectors of the group usually stop, so two cylinders drop out. P2148 is the opposite fault.

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

Symptoms

• Two cylinders misfire at once
• Heavy loss of power, rough running
• Check engine lamp on immediately

Common causes

• High Injector supply wire chafed and shorted to ground
• Medium Injector of the group shorted internally to its body
• Medium Water in the injector harness connector
• Low Faulty injector driver in the engine control module

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