The Engine Control Module (ECM/PCM/ECU), which controls your vehicle’s computer, detects an issue with its electric cooling fan. The PCM detects temperature changes via the coolant sensor. The PCM will activate the fan if the engine temperature reaches the specified ...
Category: Diagnostic Trouble Codes
Welcome to our Diagnostic Trouble Codes Blog — your reference point for understanding what your car’s fault codes really mean.
Discover clear, easy-to-follow articles explaining OBD-II codes, common causes, symptoms, and recommended fixes across all major vehicle systems.
From check-engine lights and sensor faults to emissions and drivability issues, our content helps you move from code to cause with confidence.
Learn how to interpret fault codes correctly, avoid unnecessary repairs, and diagnose problems the smart way.
Ask4Auto Latest Articles
P0355 Fault in the Ignition Coil “E” Primary/Secondary Circuit: What is it?
The majority of modern vehicles use a coil-on plug (COP) system. This eliminates the requirement for spark plugs, distributor caps and wires. The ignition coil in this system is located directly above the plug. Each cylinder has its own coil, ...
P0300 Random/Multiple Cylinder Misfire Detected Fault: What is it?
The P0300 code means that the computer of your vehicle has detected an ignition fault (misfire) in more than one engine cylinder. Other fault codes, from P0301 through P0308, will also likely occur. This code’s last number indicates the cylinders ...
P0430 Catalyst System Efficiency Below Threshold (Bank 2) Fault: What is it?
This code may appear alongside misfire codes and oxygen sensor codes. The ECU sets the P0430 code when it detects low catalytic conversion efficiency. The code may appear when the ECU detects a low catalytic efficiency. This can be due ...
U0100 Lost Communication with ECM/PCM Fault: What is it?
The fault code U0100 indicates a loss of signals between an Electronic Control Module (ECM/PCM), and another module. A short circuit may have also caused the communication to be interrupted. All systems of modern vehicles are controlled by computers. Engine ...
P0017 Camshaft Position B – Camshaft Position Correlation (Bank 1) Fault: What is it?
The fault code P0017 may indicate that the camshaft or crankshaft of the engine is malfunctioning. These two components are vital to the engine’s performance and must be in perfect sync. The engine control module can generate the P0117 error ...
P0302 Cylinder 2 Misfire Detected Fault: What is it?
The vehicle computer (PCM/ECM/ECU), detects multiple misfires on cylinder number 2. You should not check the second cylinder of the engine firing order. Instead, you should look at the cylinder that is numbered “2” in the engine cylinder arrangement. In ...
P0141 Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 2) Fault: What is it?
What makes fault code P0141 different from the others? What makes fault code P0141 different from others?Fault Code P0141 is ‘Oxygen Sensor Heating Circuit Malfunction (Bank 1, Sensor 2)’. This fault code indicates that the oxygen sensor heater circuit (downstream), ...
U0073 Control Module Communication Bus ‘A’ Off Fault: What is it?
Error code U0073 means ‘Control Module Communication Data Line “A” Closed’. This error code is generally triggered when the communication between the control modules of your vehicle is completely or partially lost. This code is only applicable to fuel-injected engine ...
P0010 Camshaft Position ‘A’ Actuator Circuit (Bank 1) Fault: What is it?
The engine’s variable valve timing (VVT system) is the cause of fault code P0010. The Engine Control Module’s (ECM/PCM/ECU), if it has set the fault code P0010 indicates a problem with the solenoids of the VVT that send oil pressure ...