P217B: Fuel Injector Group G Supply Voltage Circuit Low

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.

Medium severity. Can I keep driving?Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

Symptoms

Check engine lamp on immediately
Cylinder 7 misfire, reduced power

Most likely causes

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

What to check, in order

Start with the simplest. You can tick off each step.

Check the connector and wiring of the injector indicated
With the connector unplugged, check whether the signal wire is making contact with ground.
Measure the resistance and compare it with the manufacturer's specification
Check the control signal with an oscilloscope; on direct injection or diesel engines, leave this to a repair shop because of the high voltages
On diesels, check the per-cylinder injection corrections

Good to know

Repair difficulty: hard
It can trigger limp mode.
It affects emissions.

What each character of P217B means

P: Powertrain: engine and transmission
2: Generic code: same on every make
1: Air and fuel
7B: Specific fault in that system

Frequently asked questions

Can I keep driving with code P217B?

Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.

What causes code P217B?

The most common causes are: cylinder 7 feed wire grounded at the rear of the engine; cylinder 7 injector shorted to ground; engine control module output stage faulty.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.