The small turbo petrol of Cruze and Trax. Cooling leaks, the valve-cover PCV and the turbo wastegate are typical - hence the frequent P0299 and P0171 duo.
Click a code for the full breakdown: symptoms, causes, and whether you can keep driving.
Turbocharger Underboost
The turbo is producing less boost pressure than the ECU requests.
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.
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.
Coolant Temperature Below Thermostat Regulating Temperature
The engine takes too long to warm up - the ECU sees coolant temperature staying below where the thermostat should regulate it.
Turbocharger Overboost Condition
Boost pressure exceeded the safe limit - the wastegate or boost control is not relieving pressure.
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.
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