System
Emissions & exhaust
DPF, EGR, AdBlue and SCR, NOx, catalysts and lambda sensors: the codes behind most warning lights on modern diesels.
69 real cases · Page 3 of 3
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Diagnosing P0403 and P0121 on a SKODA Yeti 2.0 TDI
Learn how to diagnose overlapping P0403 and P0121 faults on a VAG EA288 engine, from shared wiring harness failures to carbon sludge binding. -
Diagnosing P0299 Alongside an AdBlue Fault
A concrete diagnostic case of a 2016 diesel with a P0299 underboost code and an AdBlue fault, exploring charge air leaks, VNT issues, and DPF blockage. -
Diagnosing a P0420 on a 2011 Honda CR-V
A 2011 Honda CR-V presented with a P0420 fault code. We break down the diagnostic path, exploring catalyst degradation, secondary O2 sensors, and exhaust leaks. -
Diagnosing a P0420 on a 2012 Ford Focus III
A breakdown of a P0420 diagnosis on a 2012 Ford Focus III, exploring catalytic converter degradation, exhaust leaks, and a hidden EVAP purge valve issue. -
Diagnosing P0420 and C1201 on a 2005 Toyota Yaris II
A real diagnostic case study of a 2005 Toyota Yaris II with P0420 and C1201 codes, covering structured testing for catalysts, exhaust leaks, and O2 sensors. -
Diagnosing P2002 and P20EE with a Countdown
A 2016 diesel presented with P2002, P20EE, and a 250-mile no-start countdown. See how DPF backpressure and DEF dosing failures connect in this diagnostic case. -
Diagnosing P2002 on a 2020 Ford Transit Connect II
A detailed look at diagnosing code P2002 on a 2020 Ford Transit Connect II, exploring DPF saturation, sensor failures, and exhaust leaks. -
Diagnosing P24C6 on a 2019 Ford Tourneo Custom
A detailed look at diagnosing a P24C6 fault code on a 2019 Ford Tourneo Custom, covering PM sensor failures, wiring issues, and exhaust leaks. -
Resolving AdBlue Code P2BA9FD on a Mercedes V-Class
A step-by-step diagnostic breakdown of AdBlue fault code P2BA9FD on a 2014 Mercedes V-Class, covering fluid quality, dosing valves, and NOx sensors. -
Resolving P030273 and DPF Codes on a 2016 Mercedes Vito
A 2016 Mercedes Vito shows DPF fault codes P246B09 and P246392 alongside a cylinder misfire. Learn how to diagnose the root cause and save bay time. -
Diagnosing a P0471 Code on a 2015 Nissan Navara
A 2015 Nissan Navara NP300 II presented with a P0471 code and exhaust fumes in the cabin. We break down the diagnostic path for this specific vehicle fault. -
Renault Express P2000: Beyond the NOx Sensor
A 2020 Renault Express II with P2000, P1024, and P1006 codes usually points to sulfur poisoning rather than a failed NOx sensor. Explore the diagnostic path. -
Diagnosing P0131, P14AB, and P0441 on a 2017 VW Golf VII
Explore a real diagnostic case on a 2017 VW Golf VII with P0131, P14AB, and P0441 codes. Learn how an open EVAP valve triggers false lean sensor readings. -
Diagnosing a Stalling 2010 VW Golf VI With a P2251 Code
A 2010 Volkswagen Golf VI arrived with a P2251 oxygen sensor code and a stalling complaint. Here is how we evaluate conflicting codes and physical symptoms. -
Diagnosing a Cascading Electrical Failure on a 2014 Audi A6
A 2014 Audi A6 enters the shop misfiring with 11 fault codes across the injectors, EGR, AdBlue, and DPF systems. Here is how to sequence the diagnosis. -
Diagnosing P0402 on a 2016 VW Multivan T6
A 2016 Volkswagen Multivan T6 presents a P0402 code. We break down the diagnostic path from carbon buildup to MAF signal drift on the 2.0 TDI engine. -
Diagnosing a P0140 No Activity Code on a 2001 VW Bora
Explore a diagnostic case study of a 2001 VW Bora with a P0140 code. Discover why oxygen sensor inactivity involves more than just swapping the sensor. -
Diagnosing Overlapping Faults on a 2012 VW Polo V
See how Wrenchlane analyzed P0671, P0672, P0673, and P0405 alongside physical symptoms to guide a fast, accurate diagnosis on a 2012 Volkswagen Polo V. -
Diagnosing P20EE on a 2021 Toyota Proace Verso II
Step-by-step diagnostic breakdown of a P20EE code and AdBlue system warning on a Toyota Proace Verso II, exploring dosing, fluid, and sensor tests. -
Diagnosing P049B on a 2009 Mercedes-Benz C-Class (W204)
Explore the real diagnostic path for a P049B code on a 2009 Mercedes-Benz W204. Learn why carbon buildup and sensor faults trick the ECM on OM651 engines. -
Diagnosing a W211 E-Class with Multiple Independent Faults
Explore a real diagnostic case on a 2006 Mercedes W211 addressing accelerator pedal correlation codes, oxygen sensor failures, and glow plug issues.