PROBLEMS & DIAGNOSTICS
2015 Chevrolet Silverado 1500 Check Engine Light & OBD-II Codes
Read the stored diagnostic trouble codes and freeze-frame information before replacing parts; a code identifies a circuit or condition, not necessarily a failed component.
Confirm the engine, trim, drivetrain, market and installed equipment before using a part number, capacity or repair procedure.
Common code definitions
Browse the entries below.
| Code | General diagnostic meaning |
|---|---|
| P0300 | Random/multiple-cylinder misfire |
| P0171 | Fuel system too lean, Bank 1 |
| P0174 | Fuel system too lean, Bank 2 |
| P0420 | Catalyst efficiency, Bank 1 |
| P0430 | Catalyst efficiency, Bank 2 |
| P0442 | Small EVAP leak |
| P0455 | Large EVAP leak |
| P0700 | Transmission control system requests MIL |
| P0741 | Torque-converter clutch performance / stuck off |
These definitions are general OBD-II starting points. Diagnose using the exact vehicle and code subtypes.
What the light means
A steady light generally calls for diagnosis soon. A flashing light can indicate active catalyst-damaging misfire and needs immediate caution. Record all codes, including pending and transmission-related information, before clearing them.
A practical diagnostic order
Inspect obvious fluid leaks, loose electrical connectors and current vehicle symptoms. Compare codes with known operating conditions; one problem can cause several codes. Clearing the light before recording data makes the underlying fault harder to identify.
- P0300: random/multiple-cylinder misfire.
- P0420/P0430: catalyst efficiency below threshold on the specified bank.
- P0442/P0455: evaporative-system leak detection faults.
- P0700: transmission controller requests a warning light.
Which code page should I read?
Start with P0300 for misfires, P0171/P0174 for lean fuel mixture, P0442/P0455 for EVAP leaks, and P0420/P0430 for catalyst monitoring. Codes P0700 and P0741 call for identifying the transmission and inspecting related TCM and converter-clutch information, not clearing the light and replacing parts blindly.
Use the correct model-year manual and current service information. Stop if instructions or safety precautions are unclear, and use a qualified technician for work you cannot verify.
References and further reading
This independent guide is not endorsed by the vehicle manufacturer. Let us know if you spot an error.