Code Definition

P1200 — Injector control circuit

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

About P1200

P1200 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 P1200 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.

P1200 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

Fuel injectors are supplied with battery voltage through the ignition circuit or an injector fuse, and the Engine Control Module (ECM) completes the circuit by switching the injector ground side on and off through an internal low side driver. The ECM continuously monitors the voltage on each control circuit and expects to see a specific pattern, including the inductive kick spike of around 60V to 80V that appears when the driver turns off and the injector coil collapses. DTC P1200 is set when the ECM detects that the injector control circuit is not behaving as expected, which covers an open ci...

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