Cylinder 7 Injector Restricted
The P02B4 code indicates that the engine control module (ECM) has detected a restriction in the fuel injector for cylinder 7. This means the injector is not delivering the proper amount of fuel, often due to clogging or internal damage. The ECM monitors fuel trim and injector circuit performance; when it sees a deviation, it sets this code. A restricted injector can cause lean misfires, reduced power, and increased emissions.
01. Most Common Causes
- Clogged fuel injector due to debris or carbon buildup
- Faulty injector internal solenoid or stuck pintle
- Contaminated fuel (water, dirt, or poor quality)
- Wiring or connector issues at the injector
02. Symptoms You Will Notice
- Engine misfire on cylinder 7
- Rough idle or hesitation during acceleration
- Check Engine Light illuminated
- Decreased fuel economy and power loss
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Perform a cylinder contribution test to confirm cylinder 7 is weak.
Step 3: Inspect injector wiring and connector for damage or corrosion.
Step 4: Swap injector 7 with another cylinder and see if the code moves.
Step 5: If code follows, replace the injector; if not, check fuel pressure and contamination.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with a restricted injector can cause misfires, catalytic converter damage, and poor performance. Have it diagnosed promptly.
How much does it cost to fix?▼
Replacing a single fuel injector typically costs $150-$400 including parts and labor. Diagnosis may add $100-$150.