Code
P0201
AUDI
P — Powertrain
Defective Fuel Injector, Faulty or corroded Fuel Injector, wiring, and or connections, Plugged Fuel Injector, Dirt in the Fuel Injector
Views:
UK: 22
EN: 58
RU: 64
AI status
Completed
Completed
100%
Causes
- Open or shorted injector wiring for cylinder 1
- Corroded/loose injector connector or terminal
- Failed fuel injector (stuck open/closed or internal short)
- Plugged or partially clogged injector causing abnormal current/pulse behaviour
- Faulty ECM injector driver or ground
- Intermittent wiring fault from vibration or heat
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Rough idle or misfire on cylinder 1
- Reduced engine power, hesitation, or poor acceleration
- Increased fuel consumption or black smoke from exhaust (rich condition)
- Hard starting or extended cranking
- Possible fuel odor from leaking injector
What to check
- Read and record all stored DTCs and freeze-frame/live-data for context
- Inspect the injector connector and wiring harness for corrosion, damage, loose pins or water entry
- Visually check for fuel leaks at the injector
- With key OFF, disconnect connector and measure injector resistance across terminals (compare to factory spec)
- With key ON (engine off), check battery voltage at the injector supply pin
- Check continuity between injector control pin and ECU injector driver pin (engine off)
Signal parameters
- Injector supply voltage: ~Battery voltage (with key ON); should be near 12 V — verify before testing injector driver
- Injector control: pulsed (PWM) ground or switched ground from ECU; pulse width varies with load and RPM
- Injector resistance: consult Audi factory specification for this model/year (typical values vary; do not rely on generic numbers)
- Noid light: should flash when cranking or running if ECU is commanding injector
- Oscilloscope: square-wave pulses on control pin and steady battery-level supply on power pin; abnormal waveforms indicate driver or wiring faults
Diagnostic algorithm
- Connect a professional scan tool, read freeze-frame and live data, then record any related codes (e.g., misfire codes).
- Visually inspect injector 1 connector and harness for corrosion, damaged insulation, broken wires, or water ingress; repair any damage.
- With ignition OFF, disconnect injector 1 and measure DC resistance across the injector terminals; compare to factory spec to identify open/shorted coil.
- With ignition ON (engine off) check for battery voltage at the injector supply pin; if missing, trace supply fuse/relay/power feed.
- Check continuity between the injector control pin and the ECU driver pin (pin-to-pin) to confirm no open circuit; check for shorts to ground or battery.
- Use a noid light or oscilloscope on the injector control connector while cranking/running to verify injector pulse signal and waveform integrity.
- If electrical checks are good but symptoms persist, perform an injector flow or balance test (service cleaner/bench test or flow meter) to detect clogging or poor spray pattern.
- Swap the suspect injector with another cylinder’s injector (if same type) and see if the code or misfire moves with the injector — if it does, replace the injector.
- If swapping does not move the fault, suspect wiring or ECU driver; repair harness faults or test/replace ECU as a last resort after verifying wiring and power/grounds.
- After repairs, clear codes, perform extended functional check/road test and verify no reoccurrence of P0201 and related misfires.
Likely causes
- Damaged or corroded connector at injector (most common)
- Open or short in the harness between injector and ECU
- Failed injector (electrical/solenoid failure)
- Intermittent wiring fault (broken strand, chafing)
- ECM output driver failure (less common)
Fault status
Status
P0201 - Fuel injector circuit fault detected for cylinder 1. ECM has logged injector control anomaly (open, short, or abnormal current/pulse).
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Workshop Manuals
Repair manuals for AUDI
11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop ManualAudi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop ManualAUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop ManualAudi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop ManualAudi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop ManualAudi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop ManualAudi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop ManualAudi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop ManualAudi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop ManualAudi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop ManualAudi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
