Code Definition

P1222 — Injector circuit cylinder 1 intermittent

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1222

P1222 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1222 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1222 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The cylinder 1 fuel injector is supplied with battery voltage whenever the ignition is on and the Engine Control Module (ECM) completes the circuit by switching the ground side through an internal low side driver, monitoring the voltage on the control line to confirm the injector is behaving as expected. DTC P1222 is set when the ECM detects an intermittent fault in the cylinder 1 injector control circuit, meaning the circuit works correctly most of the time but momentarily opens, shorts or fails to switch. The intermittent nature is the defining feature of this code, and it points firmly at a...

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