P217B: Fuel Injector Group G Supply Voltage Circuit Low

What does P217B mean?

P217B reports the feed of injector group G as grounded, which on GM's direct-injection V8 engines is the injector of cylinder 7, at the rear of bank 1. GM's 2016 table 16OBDG07A and the 2018 LT4 table of the supercharged 6.2 V8 measure it with the driver switched on: if 25 A or more flows through the high side, the line is grounded somewhere. The check runs every 100 ms as soon as the battery has 11 V; 10 failures in 20 samples set the code as type A, so the MIL comes on in the same trip. Check the harness routing at the rear of the engine and the injector connector before suspecting the module. The module stops firing the injector, which shows up as a cylinder 7 misfire. P217C is the high fault, P217A the general one.

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

Symptoms

• Check engine lamp on immediately
• Cylinder 7 misfire, reduced power

Common causes

• High Cylinder 7 feed wire grounded at the rear of the engine
• Medium Cylinder 7 injector shorted to ground
• Low Engine control module output stage faulty

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