The three-cylinder turbo petrol of Fiesta and Focus. Early years had cooling system and wet-belt issues; coils and plugs are routine wear.
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.
Turbocharger Underboost
The turbo is producing less boost pressure than the ECU requests.
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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