P0171 Diagnostic Guide
P0171 may indicate the fuel trim correction has moved too far in the lean direction for the controller to compensate.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Engine diagnostics
Published vehicle-specific guides in this diagnostic system.
P0191 Diagnostic Guide
P0191 may mean the engine controller is seeing a fuel rail pressure sensor performance problem, often because the pressure readings do not agree the way the controller expects.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P0201 Diagnostic Guide
P0201 may mean the engine control module is seeing a possible problem with the cylinder 1 fuel injector control circuit.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Wait to Start Indicator Control Circuit
P0381 may mean the ECM commanded the wait to start indicator, but the circuit response may not match the commanded state.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Exhaust Gas Recirculation Flow Insufficient
P0401 means the engine computer may be seeing less EGR flow response than expected when it commands EGR operation.
Article vehicle: 2020 25 Chevrolet Silverado 2500 6.6 diesel
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Exhaust Gas Recirculation Control Circuit
P0403 generally means the vehicle may be detecting an electrical control problem in the EGR valve circuit rather than a basic flow or soot concern by itself.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Exhaust Gas Recirculation Open Position Performance
P0404 means the EGR valve position may not be matching what the engine control module expects when it commands the valve.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Exhaust Gas Recirculation Open Position Performance
P0404 may mean the control module is commanding EGR valve movement, but the measured EGR position may not match the desired position as expected.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P0405 Diagnostic Guide
P0405 usually means the controller may be seeing the EGR position feedback lower than expected.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Transmission Control Module Requested MIL Illumination
P0700 often means the transmission control module may have detected an emissions-related transmission fault and requested the malfunction indicator lamp through the vehicle network
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Torque Converter Clutch System Stuck Off
P0741 may mean the transmission control system is not seeing the torque converter clutch apply or hold as expected.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Reductant Heater 1 Control Circuit Shorted to Control Circuit
P10D9 may mean the DEF reductant heater control circuit is seeing a possible circuit-to-circuit fault.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P115E Diagnostic Guide
P115E may indicate that NOx Sensor 1 is not operating within the range the control module expects.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P119D Diagnostic Guide
P119D may indicate the downstream NOx Sensor 2 signal is not matching the range the control system expects.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P2002 Diagnostic Guide
P2002 may indicate that the diesel particulate filter is not reducing soot as efficiently as expected.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P20E8 Diagnostic Guide
P20E8 may indicate the reductant pressure is lower than expected in the diesel exhaust fluid aftertreatment system.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P20EE Diagnostic Guide
P20EE may mean the SCR NOx catalyst efficiency is being judged lower than expected by the engine control system.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Particulate Filter Regeneration Frequency
P2459 may mean the diesel particulate filter regeneration frequency is not matching what the control module expects.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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P24A0 Diagnostic Guide
P24A0 may indicate the closed loop particulate filter regeneration temperature control is at its limit on the low-temperature side.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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Idle Speed High
P0507 may mean the engine is idling higher than the control module is requesting.
Article vehicle: 2020-2025 Chevrolet Silverado 2500 6.6 diesel
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