Code
P0265
GWM
P — Powertrain
- High Injector Circuit Value 2 Cylinder
Views:
UK: 3
EN: 5
RU: 5
AI status
Completed
Completed
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Causes
- Open, broken, or high-resistance wiring in the injector feed or return/driver circuit for cylinder 2
- Corroded, loose, or damaged connector or terminal at the injector
- Faulty fuel injector (internal coil or driver fault increasing circuit resistance)
- Poor or intermittent ground or fused power supply to the injector rail
- Faulty ECM/PCM driver output for injector 2
- Aftermarket or improper repairs/harness modifications introducing high resistance
Symptoms
- Check Engine Light (MIL) illuminated with P0265 stored
- Rough idle or misfire felt from cylinder 2
- Reduced engine power or hesitation under load
- Hard starting or increased cranking time
- Increased fuel consumption and possible increased smoke (diesel engines)
What to check
- Read stored codes and freeze frame data with a scan tool; record pending codes and misfire counts
- Visually inspect injector harness, connector, and wiring for damage, corrosion, or pin push-out
- Backprobe injector connector and measure supply voltage and driver signal with key ON and engine cranking/running
- Measure injector coil resistance at the injector and compare to manufacturer specification
- Check continuity and resistance from injector connector to ECM pin to detect high resistance or opens
- Inspect and test fuses/relays and ground points related to the injector circuit
Signal parameters
- Injector coil resistance: should be within manufacturer specification. (Typical low-impedance injectors ~0.5–3 Ω; high-impedance types ~6–20 Ω — consult service manual for exact value.)
- Supply voltage to injector: battery voltage (approx. 12 V) on the supply side when key ON
- Driver/ground side when commanded: pulsed to ground by ECM; voltage on driver will switch per command
- Injector current draw: should match expected waveform and amplitude for the injector type when energized (use oscilloscope or amp clamp)
- ECM monitored circuit voltage: ECM expects certain voltage range across the circuit; values outside that range trigger P0265
Diagnostic algorithm
- Confirm code: Clear codes and perform key cycles/short road test to see if P0265 returns and record freeze-frame data.
- Visual inspection: Check connector pins, wiring harness, insulation, and nearby components for chafing, corrosion, or heat damage.
- Connector check: Disconnect injector 2 connector and inspect pins for corrosion, bent/pushed pins, or water intrusion.
- Resistance test: With engine OFF and harness disconnected, measure injector coil resistance at the injector terminals and compare to spec. If resistance is significantly higher or open, replace the injector.
- Supply and driver voltage: Backprobe connector with harness connected. Verify constant 12 V supply on the feed side and that the ECM switches the driver side to ground when commanded. No supply or abnormal voltage indicates wiring/fuse/relay issue.
- Continuity and voltage drop: Measure continuity and resistance from injector connector to ECM connector pin. Check for high resistance or intermittent open. Wiggle test harness while monitoring for changes.
- Swap test: If practical, swap injector 2 with another known-good injector and rerun test to see if the code follows the injector or stays with cylinder 2 (follows = bad injector; stays = wiring/ECM).
- Dynamic test: Use an oscilloscope or injector tester to view the injector drive waveform and measure current draw while cranking/running. Look for abnormal waveform shape or low current indicating high resistance.
- Check ECM: If injector and wiring check good, inspect ECM connector for corrosion and test/replace ECM only after eliminating harness and injector faults.
- Repair and verify: Repair/replace faulty component(s), clear codes, and verify proper operation and that the fault does not return under normal conditions.
Likely causes
- Corroded or pushed-out terminal in the injector connector
- Broken wire in the harness near the injector or at a harness flex point
- Injector coil degraded (higher than spec resistance)
- Blown or poor fuse/relay supplying injector rail
- ECM driver channel damaged (less common)
Fault status
Status
P0265 - Injector Circuit High (Cylinder 2) — Electrical resistance/voltage out of expected range in injector circuit for cylinder 2. Inspect injector, wiring, connector, power/ground, and ECM driver.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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