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VOLKSWAGEN
P2187
P0171
P0507

P2187 P0171 P0507 VW 2.0 TSI – System Too Lean at Idle & High Idle RPM Diagnostics

Diagnostic Priority: High
Complexity Level: Advanced

Diagnostic guide for P2187, P0171, and P0507 on Volkswagen 2.0 TSI. Lean fuel trim at idle, higher than expected idle speed, and PCV membrane failure.

Vehicle

VOLKSWAGEN

Codes

3 units

Analysis Type

Technical Expert

Status

Analyzed

Technical Analysis

REF: #73949A

The combination of P2187, P0171, and P0507 indicates an unmetered air leak isolated to idle conditions on VAG 2.0 TSI engines, caused by a ruptured PCV diaphragm or leaking rear main seal.

Expected Symptoms

Check engine light illuminated with sudden boost drop under hard acceleration on VOLKSWAGEN (DTCs: P2187, P0171, P0507)
Rough idle and sluggish throttle pickup from a dead stop
Misfiring and hesitation during high-speed highway overtaking (2,500–3,500 RPM)

System Impact

Drivetrain
Engine Control
Emission Control

Potential Fault Sources

01Sticking electronic wastegate actuator or heavy carbon buildup on intake valves (affecting VOLKSWAGEN subsystem for P2187, P0171, P0507)
02Boost control solenoid N75 leakage or split charge air hose
03Ruptured diaphragm in PCV oil separator assembly (logged fault: P2187)

Workflow / Methodology

01

Verify supply voltage and sensor telemetry for P2187, P0171, P0507 on VOLKSWAGEN with multimeter at key ON.

02

Measure wastegate position feedback voltage at key ON: normal 3.5–3.9 V in closed position.

03

Smoke-test induction system and boost plumbing at 1.2 bar to pinpoint leaks.

04

Check crankcase depression with digital manometer at warm idle (-100 to -150 mbar).

Live Data & Mätvärdestoleranser (Är/Bör-värden)

Fabriksgodkända referensvärden vid diagnos och live-avläsning

Mätvärdesblock
Parameter / SignalTestvillkorBör-värde (Normalt)Avvikelse / Varning
GivarreferensspänningTändning på4.95 – 5.05 V< 4.75 V (Kortslutning/Spänningsfall)
Signalretur tomgångDriftstemperaturInom fabriksintervall ±5%Signalkorruption el avbrott

Assessment & Action Proposal

Technical Recommendation

Install a new genuine PCV oil separator assembly with gasket, reset fuel trim adaptations in the ECU, and clear DTCs.

Need a deeper analysis? Use our advanced fault code analyzer to find likely connections and in-depth guidance.

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Vanliga frågor om dessa felkoder

Vad är den primära orsaken till felkoderna?

The combination of P2187, P0171, and P0507 indicates an unmetered air leak isolated to idle conditions on VAG 2.0 TSI engines, caused by a ruptured PCV diaphragm or leaking rear main seal.

Kan man köra vidare med tänd motorlampa / varningslampa?

Körning med aktiva felkoder kan leda till strypt motoreffekt (nödläge / Limp Home), blockerad partikelfilterregenerering eller följdskador på mekaniska komponenter. Felsökning bör genomföras omgående.

Hur åtgärdas kombinationen på säkrast sätt?

Install a new genuine PCV oil separator assembly with gasket, reset fuel trim adaptations in the ECU, and clear DTCs.