P046C P0401 P0405 Audi 2.0 TDI EA288 – EGR Sensor A Circuit & Insufficient Flow

Diagnose-Priorität: Hoch

Komplexitätsgrad: Fortgeschritten

Diagnostic guide for P046C, P0401, and P0405 on Audi 2.0 TDI (EA288). Troubleshoot low-pressure EGR position sensor drift and cooler soot accumulation.

Fahrzeug

AUDI

Codes

3 Steuergeräte

Analysetyp

Technischer Experte

Status

Analysiert

Technische Analyse

REF: #0783F3

The combination of P046C, P0401, and P0405 indicates a low-pressure EGR valve position sensor circuit failure and insufficient flow through the EGR cooler on Audi 2.0 TDI engines.

Erwartete Symptome

Glow plug light flashing and DPF icon illuminated on instrument cluster on AUDI (DTCs: P046C, P0401, P0405)

Engine enters limp home mode restricting engine output above 2,200 RPM

Acrid exhaust odor and elevated fuel consumption due to aborted DPF regenerations

Systemauswirkungen

Antriebsstrang

Motorsteuerung

Abgasreinigung

Mögliche Fehlerursachen

01Defective differential pressure sensor G450 or split silicone sample lines (affecting AUDI subsystem for P046C, P0401, P0405)

02Severe soot loading in DPF caused by short-trip driving and fouled injectors

03Sticking EGR cooler changeover flap or faulty exhaust gas temp sensor G235 (logged fault: P046C)

Vorgehensweise / Methodik

Verify supply voltage and sensor telemetry for P046C, P0401, P0405 on AUDI with multimeter at key ON.

Check DPF differential pressure with key ON: must read precisely 0 hPa (0.48–0.52 V).

Query calculated soot mass and oil ash volume in ECM live data blocks.

Execute service regeneration cycle under load following sensor replacement.

Live Data & Mätvärdestoleranser (Är/Bör-värden)

Fabriksgodkända referensvärden vid diagnos och live-avläsning

Mätvärdesblock

Parameter / Signal	Testvillkor	Bör-värde (Normalt)	Avvikelse / Varning
EGR Ventilposition (Är)	Stängd (Motorbroms/Fullgas)	0.0 % (1.00 V)	> 3.5 % (Sotkärvning i säte)
EGR Ventilposition (Är)	Aktiv dellast	20 – 65 %	Hänger kvar / Trög reglering
Luftmassa (MAF G70)	EGR fullt öppen på tomgång	200 – 260 mg/slag	> 380 mg/slag (Otillräckligt EGR-flöde)

Bewertung & Handlungsempfehlung

Technische Empfehlung

Install a new genuine EGR cooler and valve assembly, perform EGR adaptation in the ECU, and clear DTCs.

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Vanliga frågor om dessa felkoder

Vad är den primära orsaken till felkoderna?

The combination of P046C, P0401, and P0405 indicates a low-pressure EGR valve position sensor circuit failure and insufficient flow through the EGR cooler on Audi 2.0 TDI engines.

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 EGR cooler and valve assembly, perform EGR adaptation in the ECU, and clear DTCs.