P1205 Injector Circuit Malfunction
The P1205 code indicates a fault in the fuel injector control circuit, detected by the Engine Control Module (ECM/PCM). As a manufacturer-specific code (P1xxx), its exact definition varies: on Ford Power Stroke diesel engines, it often relates to the Injection Control Pressure (ICP) sensor or the injector circuit for cylinder 5; on Hyundai/Kia and Nissan, it typically points to an open or short circuit in the injector for cylinder 5 or a general injector driver failure. The ECM detects a discrepancy between the activation command and the electrical feedback (voltage/current) from the circuit.
01. Most Common Causes
- Faulty fuel injector (open or shorted coil), usually cylinder 5
- Damaged, corroded, or shorted wiring or connectors in the injector circuit
- Failed injector driver (power transistor) inside the ECM/PCM
- Faulty Injection Control Pressure (ICP) sensor (Ford Diesel)
- Low battery voltage or faulty injector power supply relay
- Defective PCM/ECM (rare)
02. Symptoms You Will Notice
- Engine misfire or rough idle
- Check Engine Light illuminated
- Reduced engine power or poor acceleration
- Hard starting or no start condition
- Increased fuel consumption
03. Step-by-Step Diagnosis
Scan for codes and verify P1205 is present; note freeze frame data
Visually inspect injector wiring and connectors for damage, corrosion, or loose connections
Test injector resistance (typically 0.5–2 ohms) and compare to specifications
Check for battery voltage at the injector power supply and ground continuity
Perform a injector balance test or cylinder contribution test
If wiring and injector check out, test the injector driver circuit using a lab scope or test light; consider ECM replacement if driver is faulty
1. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this code is not recommended. It can cause engine misfire, reduced power, and potential damage to the catalytic converter or engine due to unburned fuel.
How much does it cost to fix?▼
Repair costs vary widely: injector replacement $200–$600 per injector, wiring repair $100–$300, ECM replacement $500–$1500. Diagnostic fees are typically $100–$200.