Diagnostic article Generic OBD-II
P245D: EGR cooler bypass circuit high under motor command
Learn why P245D is a commanded EGR bypass motor power-short diagnosis, how GM qualifies it and why current alone cannot locate the fault.
Read before applying this article
Documented application
2025 GM 04A documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
The documented P245D strategy checks whether commands to the high-pressure EGR cooler bypass valve are shorted to the power supply. Its component description names the bypass DC motor. “Circuit high” does not mean that exhaust temperature or bypass opening is excessively high.
Current and operating state belong together
A hardware-reported current above 8 A through the H-bridge switches is the failure criterion. This check runs with the H-bridge driver on, rather than proving a short merely from voltage observed while the output is idle. A technician needs the output command and driver status alongside any electrical measurement.
The sampling rule is 160 failures in 200 samples on a 12.5 ms task. Type B, two-trip reporting is listed. Enable conditions include powertrain relay supply above 11 V, completion of cranking, an enabled diagnostic system and a determinate hardware error status. A low-supply or reset interval cannot be substituted for the qualifying operating conditions.
Why the companion code matters
The ground-short monitor uses the same overcurrent limit. Consequently, an overcurrent trace by itself cannot distinguish the P245D power-short classification from the low-circuit alternative. Preserve both codes and the controller's hardware fault information before clearing the record.
Check the applicable schematic for the motor's two driven connections and the controller output arrangement. Neither “high” nor the 8 A criterion identifies a particular connector pin. Position feedback and cooler-flow complaints may provide additional evidence, but they do not replace this electrical assessment. The summary table supplies a detection strategy, not a basis for replacing the complete cooler assembly.
Source and applicability
2025 GM 04A documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 1194.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
EGR Cooler Bypass Control Circuit High Bank 1
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT