P2054: DEF valve 2 low-side ground-short supervision

P2054 is the circuit-low code for bank 1, unit 2 of the reductant injection system. The GM row reviewed here specifically monitors a low-side short to ground on DEF metering valve 2. The evidence is supplied by the control hardware rather than inferred from catalyst behavior.

Channel and fault direction both matter

The second-valve hardware interface must report its ground-short state as faulted. Its result must also be determinate. These requirements distinguish P2054 from an open circuit, a short toward battery supply and an unavailable hardware diagnosis, even though all can concern the same dosing valve.

The table gives no fixed terminal voltage or resistance to reproduce with a meter. Applying generic limits would add a test that the source does not support. It also gives no basis for assuming that the valve itself, rather than another part of its circuit, must be replaced.

An eligible confirmation

The monitor requires calibration enablement, battery voltage above 11 volts and key-on or engine-running operation, with cranking excluded. Thirty failures in 60 samples qualify the condition on a 100-millisecond time base. The listed reporting is Type A, one trip.

Verification should establish a valid, nonfaulted ground-short diagnosis for valve 2 after those conditions are satisfied. Pump-pressure recovery or a successful test of valve 1 cannot substitute for that channel-specific result. Component identification and electrical isolation must follow the vehicle's service information; this explanation covers only the 2025 GM monitor described in the source.

Source: GM monitor, PDF page 778.