Code
DF027
RENAULT
D
-> P0202 - Injector control circuit cylinder 2
Views:
UK: 2
EN: 7
RU: 5
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between ECU and injector (cylinder 2)
- Corroded, loose or damaged injector connector
- Failed fuel injector (electrical open or short)
- Faulty ECU/engine control module driver for injector 2
- Poor or missing power supply or ground to the injector circuit
- Intermittent contact due to vibration, heat or damaged insulation
Symptoms
- Engine misfire on cylinder 2, rough idle or poor running
- Warning lamp illuminated (MIL/Check Engine)
- Reduced power, hesitation or stumbling under load
- Increased fuel consumption and/or emissions
- Possible hard starting or non-start if circuit is open
What to check
- Read and record freeze-frame data and related codes (P0202, misfire codes, supply/ground faults)
- Visual inspection of injector 2 connector, wiring harness and ECU connector for damage/corrosion
- Check for proper battery voltage at injector supply (with key on)
- Measure injector coil resistance (compare to manufacturer spec or other cylinders)
- Check continuity and short to ground/short to battery between injector connector and ECU pin
- Wiggle test wiring with scan tool monitoring to reproduce intermittent faults
Signal parameters
- Injector supply (key ON): typically battery voltage (~11–14 V) at the supply pin
- Injector driver output (when off): near battery voltage (~11–14 V); when energized driver sinks to near 0 V
- Typical pulse widths at idle: ~2–10 ms (increases with load/RPM); varies by engine
- Injector coil resistance: varies by injector type — low impedance ~2–5 Ω, high impedance ~12–16 Ω (check OEM spec)
- Waveform should show clean switching edges without excessive noise, and no constant short to ground or open circuit
Diagnostic algorithm
- Retrieve all stored DTCs and freeze-frame data. Note related misfire or supply/ground codes.
- Visually inspect injector 2 connector and wiring for damage, corrosion, pins pushed out or water ingress.
- With ignition OFF, disconnect injector connector and measure injector coil resistance; compare to OEM spec and other cylinders.
- With ignition ON (engine off), verify battery voltage present at the injector supply terminal. Check continuity from supply pin to fuse/relay.
- Back-probe injector driver pin with multimeter/oscilloscope while cranking/idle to observe switching: verify pulse voltage swings between near battery voltage and ~0 V when energized.
- Check for shorts: measure resistance from injector control pin to battery positive (short to B+) and to chassis ground (short to ground).
- Perform wiggle test along harness while monitoring live data or waveform to detect intermittent faults.
- Swap injector 2 with another cylinder's injector (if identical) and clear codes; if code follows injector, replace injector.
- If code remains on cylinder 2 after swap, trace wiring back to ECU and test continuity to the ECU pin; inspect ECU connector and grounds.
- If wiring and injector check OK, consider ECU driver fault — confirm with manufacturer diagnostics before ECU replacement.
- After repair, clear codes and verify proper operation over road test and re-check for reappearance.
Likely causes
- Damaged wiring harness near injector (chafing, pinched)
- Corroded/loose connector pins at injector
- Failed injector coil (open/high resistance) on cylinder 2
- ECU driver transistor fault (less common)
- Blown fuse or relay affecting injector supply (if shared)
Fault status
Status
DF027 -> P0202: Injector control circuit fault, cylinder 2. ECU detected an electrical problem (open/short/high resistance or intermittent) in the injector driver/wiring for cylinder 2. Check wiring, connector, injector and ECU driver.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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