P0101 Code – MAF Sensor Range / Performance
Acasa › Blog › obd2 What Does P0101 Code Mean The P0101 diagnostic trouble code indicates that the engine control unit (ECU) has detected an abnormal signal from the Mass…
OBD2 is the standard on-board diagnostic system in modern vehicles. The engine control unit logs faults as trouble codes (such as P0171 or P0420), and a scan tool plugged into the OBD port reads them along with live engine data.
This page collects our OBD2 guides: individual code explanations (P0102, P0125, P0129, P0138, P0171, P0420, P0507, P059F and more), brand-specific code guides for Ford and Opel, winter-related codes, live-data checks, and notes on scan tools and VAG security gateway (SFD/SGW) access.
A trouble code does not tell you which part to replace. It only shows where the control unit noticed a problem. That is why each guide goes beyond the code itself: what to check first, which parameters to watch, and when the real cause is somewhere else. The articles are written for roadside and mobile diagnostics, based on real cases.
P0304 Code – Cylinder 4 Misfire Detected
Acasa › Blog › obd2 What Does the P0304 Code Mean The P0304 code indicates that the engine control unit (ECU) has detected a misfire in cylinder 4. A misfire…
P0302 Code – Cylinder 2 Misfire Detected
Acasa › Blog › obd2 What Does the P0302 Code Mean The P0302 code indicates that the engine control unit (ECU) has detected a misfire in cylinder 2. A misfire…
P0301 Code – Cylinder 1 Misfire Detected
Acasa › Blog › obd2 What Does the P0301 Code Mean The P0301 code indicates that the engine control unit (ECU) has detected a misfire in cylinder 1. A misfire…
P0174 Code – System Too Lean Bank 2
Acasa › Blog › obd2 What Does the P0174 Code Mean The P0174 code indicates that the engine control unit (ECU) has detected a lean air-fuel mixture on bank 2…
P0172 Code – Engine Running Too Rich
Acasa › Blog › obd2 What Does the P0172 Code Mean The P0172 code indicates that the engine control unit (ECU) has detected a fuel mixture that is too rich.…
P2453 – DPF Sensor Range Problem!
Acasa › Blog › obd2 The P2453 fault code indicates that the DPF differential pressure sensor is reporting values outside the expected performance range. Unlike P2452 (electrical circuit fault), P2453…
P2452 – DPF Sensor Circuit Fault!
Acasa › Blog › obd2 The P2452 fault code indicates a circuit malfunction in the DPF differential pressure sensor. Without accurate pressure readings, the ECM cannot properly control regeneration cycles.…
P0100 – MAF Circuit Failure?
Acasa › Blog › obd2 The P0100 – MAF Circuit code is one of the most common intake-related OBD2 faults. When triggered, the engine control module detects a malfunction within…
P0402 – EGR Excessive Flow? Diesel Power Loss!
Acasa › Blog › obd2 The P0402 fault code signals that the Exhaust Gas Recirculation (EGR) system is flowing more exhaust gas than the engine control module (ECM) expects under…