DIAGNOSIS WITH VEHICLE CONTEXT

Follow the evidence.

Find a guide for your code and vehicle. Each article explains the findings that change the diagnosis, with the model, engine and year limits shown up front.

32 diagnostic guides

Audi · P0299 / P029900

Audi A4 P0299: confirm the CAEB wastegate diagnosis

A4 CAEB: distinguish intake faults, sporadic codes and confirmed wastegate wear before replacing a turbocharger.

Audi A4

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Porsche · P0299

2015 Porsche Macan Turbo P0299: software or hardware?

Use recorded rpm, engine load and DME version to guide diagnosis before parts.

Porsche Macan

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Toyota · P0300 / P0305 / P0306 / P1605 / P030000 / P030027 / P030085 / P030500 / P030600 / P160500

Toyota Camry and Avalon V6 P0300: when calibration is the right branch

Match the high-load event and installed calibration before programming.

Toyota Camry · Toyota Avalon

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Honda · P0300 / P0301 / P0302 / P0303 / P0304 / P0172

Honda CR-V P0300 and P0172: separate update, plug and camshaft branches

2017–2018 CR-V: repair history, spark-plug findings and a separate noise inspection determine which Honda procedure applies.

Honda CR-V

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Acura · P0430

Acura MDX and TLX P0430: check software before condemning the catalyst

Acura's documented P0430 software case requires exact vehicle eligibility and transmission-software confirmation.

Acura MDX · Acura TLX

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Lexus · P0430

2010 Lexus RX450h P0430: the B2S2 result that changes the repair

The RX450h bulletin selects a bank-2 downstream oxygen-sensor repair only after a specific warm-engine scan result.

Lexus RX450h

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Toyota · P0A80 / P0A7F / P1AC000 / P1A8000

Toyota Prius P0A80 and P0A7F: what cooling-fan debris does—and does not—prove

Understand Toyota's debris-related hybrid-battery case without mistaking fan cleaning for a guaranteed battery repair.

Toyota Prius

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Honda · P0301 / P0302 / P0303 / P0304

Honda Accord V6 P0301–P0304: software, fouled plugs or piston rings?

Plug fouling, software and cylinder codes select the documented repair branch.

Honda Accord

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Ford · P0300 / P0301 / P0302 / P0303 / P0304 / P0305 / P0306 / P0316 / P0171 / P0174 / P2196 / P2198

2018 F-150 P0300 and P0171: when injectors are actually implicated

Follow the code and build-date branches before approving injector replacement.

Ford F-150

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Chevrolet / GMC · P0171 / P0174

Colorado and Canyon P0171 + P0174: inspect connections, then calibration

A paired-code case for 2020–2021 LGZ trucks, with a defined path if faults return.

Chevrolet Colorado · GMC Canyon

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Chevrolet / GMC · P0420 / P0430

Silverado and Sierra P0420/P0430: check the airbox before exhaust parts

Look for an intake sealing failure before authorizing catalyst or oxygen-sensor work.

Chevrolet Silverado · Chevrolet Suburban · Chevrolet Tahoe · GMC Sierra · GMC Yukon

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Chevrolet · P0171 / P1101 / P0106 / P0299 / P0507 / P2096

Chevrolet Cruze P0171/P1101: the PCV leak and manifold valve check

Distinguish a leaking camshaft-cover diaphragm from the intake-manifold cause that can damage it.

Chevrolet Cruze

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Ford · P1450 / P0456

Ford Escape/Fusion P1450 after refueling: match the purge-valve case

Separate a documented post-refueling start problem from a capless-inlet warning.

Ford Escape · Ford Fusion

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Ford · P2111 / P2112

F-150 P2111/P2112: why the 2015 and 2016 repair branches differ

Use the VIN-specific 16B32 history before treating every throttle-control fault alike.

Ford F-150

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Audi · P2187 / P2279 / P1297

Audi A3/A4 P2187, P2279 or P1297: match the PCV hardware first

Identify the applicable hardware and update history.

Audi A3 · Audi A4

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Audi · P2279 / P227900 / P0507 / P050700

Audi A8 P2279/P0507 and a warm-idle whistle: the two-check breather diagnosis

Two observations must agree before this Audi bulletin supports an oil-separator replacement.

Audi A8

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Volkswagen · P0401 / P2002 / P240F

VW Golf/Jetta TDI P0401: the DPF and EGR-filter repair

A soot finding, airflow check and adaptation determine this repair.

Volkswagen Golf · Volkswagen Jetta

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Volkswagen · P0420 / P0430

2018 VW Atlas P0420/P0430: why the catalyst and software repair go together

Identify the applicable Atlas bulletin and distinguish catalyst faults from the separate software-only code group.

Volkswagen Atlas

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BMW · 29E0 / 29E1 / 2B16 / 2B17 / 2B18 / 2B19 / 2B1A / 2B1B / 2B1C / 2B1D / 2B22 / 2B23

BMW X6 N63 29E0 and misfire faults: one injector or an entire bank?

Native codes, test results and injector indexes explain the repair quantity.

BMW X6 xDrive50i

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Mercedes-Benz · P0128 / P012800

Mercedes P012800 on M270/M274: check software and the thermostat test

Engine identity and a cold-start check determine the appropriate diagnosis.

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Hyundai · P0128

Hyundai P0128: when the answer is a thermostat, and when it is software

Compare the 2017 Elantra thermostat campaign with the 2018 Elantra GT and 2019 Veloster 1.6T software campaign before authorizing a repair.

Hyundai Elantra GT · Hyundai Veloster · Hyundai Elantra

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Kia · P0011 / P0014 / P0016 / P0017

Kia P0016: Soul reluctor alignment or Forte adaptive reset?

A post-replacement Soul timing fault and a scoped Forte CVVT condition require different checks. Compare the evidence before replacing another part.

Kia Soul · Kia Forte

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Jeep · P0456 / P1CEA / U0100

2019 Jeep Renegade P0456: test for a leak before the software update

Understand the leak-test result, software status and capless filler on the 2019 Renegade 1.3L.

Jeep Renegade

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Dodge · P0455 / P0456 / P0440 / P0441

2022 Dodge Challenger P0456 or P0455: choose the correct EVAP bulletin

Compare the EZH, EZC and ESG engine bulletins, understand the manual-transmission completion step, and separate a software case from a demonstrated leak.

Dodge Challenger

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Ram · P0128 / P0456 / P06EF / P0175 / P258B

2019 Ram 1500 eTorque P0128: check the revision and all three modules

Check the later bulletin, companion faults and PCM/HCP/TCM completion before approving an eTorque repair.

Ram 1500

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Jeep · P0456

2023 Jeep Grand Cherokee P0456: prove a filler-tube leak before replacement

Use the initial SLVT, weld-area finding and repeated leak test to evaluate a filler-tube estimate.

Jeep Grand Cherokee

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Porsche · P000A / P0011 / P000C / P0021 / P0068 / P1074 / P0300 / P1023 / P1026 / P1031 / P053F

Porsche Cayenne and Panamera camshaft codes: evidence before an engine estimate

Read the fault combination, mechanical findings and campaign history as separate pieces of evidence.

Porsche Cayenne · Porsche Panamera

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Nissan · P0442 / P0455 / P0456

2018 Nissan Rogue P0456: a loose cap or a real EVAP leak?

Separate the dashboard cap message, stored leak codes and a measured leak before replacing parts.

Nissan Rogue

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Nissan · P17F0 / P17F1

Nissan Pathfinder P17F0 and P17F1: why the repair branches differ

Understand the required judder complaint, chain-inspection branch and diagnostic-software check.

Nissan Pathfinder

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Subaru · P2682

Subaru P2682: confirm the thermo control valve and repair eligibility

Distinguish the documented sensor-intrusion concern, revised part identification and VIN-specific coverage.

Subaru Outback · Subaru Forester

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Subaru · P2764

Subaru Outback P2764: check the electrical branch before condemning the CVT

Why module location, fluid temperature and recorded circuit measurements matter to this fault.

Subaru Outback · Subaru Legacy

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Mazda · P0126

Mazda CX-5 P0126: when the thermostat-set repair applies

Check the companion code and recorded coolant temperature before choosing a cooling-system repair.

Mazda CX-5

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Looking up a definition? The code dictionary lists reference labels separately from these diagnostic guides.

Scan-report checklist · Safety boundaries · Documented vehicle cases