The heart of Silverado and Tahoe. The AFM cylinder deactivation is infamous for lifter failures - a misfire on an AFM V8 almost always leads there. Oil consumption too.
Click a code for the full breakdown: symptoms, causes, and whether you can keep driving.
Random/Multiple Cylinder Misfire Detected
The engine control unit detects misfires occurring randomly across multiple cylinders, meaning combustion is failing intermittently in more than one cylinder.
Cylinder 1 Misfire Detected
Combustion is repeatedly failing in cylinder 1. The ECU counts crankshaft speed fluctuations and attributes them to that specific cylinder.
Catalyst Efficiency Below Threshold (Bank 2)
Same fault as P0420 but on the second cylinder bank of V6/V8 engines - the catalytic converter on bank 2 is underperforming.
Catalyst System Efficiency Below Threshold (Bank 1)
The downstream oxygen sensor shows the catalytic converter on bank 1 is no longer cleaning exhaust gases efficiently.
System Too Lean (Bank 1)
The engine is getting too much air or too little fuel on bank 1 - the ECU has hit the limit of its ability to compensate.
System Too Lean (Bank 2)
The fuel mixture on bank 2 is too lean - twin of P0171 on V-engines. Both appearing together points to a shared cause.
Torque Converter Clutch Circuit Performance
The automatic transmission torque converter lock-up clutch is slipping or not engaging as commanded.
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