What Does P02A1 Mean?
The ECM has detected that the fuel injector on cylinder 2 is leaking, allowing fuel to enter the combustion chamber when the injector should be closed. This is identified through individual cylinder fuel trim analysis showing persistent maximum negative fuel correction on cylinder 2. The driver may notice rough idle, black smoke, fuel smell, a fouled spark plug, and possibly hard starting due to fuel puddling in the cylinder.
Common Causes
40%
Worn or damaged injector pintle or seat on cylinder 2, allowing fuel to drip past when de-energized
25%
Debris or carbon lodged in the injector tip preventing complete closure
15%
Weakened injector return spring failing to fully close the injector against fuel rail pressure
12%
Excessive fuel pressure causing fuel to push past a marginally sealing injector
8%
ECM driver fault keeping the injector partially energized when it should be fully off
Diagnostic Steps
1
Perform a fuel injector leak-down test: pressurize the fuel rail with the engine off, remove cylinder 2 spark plug, and observe for fuel dripping into the cylinder over 10-15 minutes. More than one drop per minute indicates a leaking injector.
2
Monitor cylinder 2 individual fuel trim; verify it is at the maximum negative correction limit, confirming the ECM is trying to reduce fuel delivery.
3
Remove and inspect the cylinder 2 spark plug; it should show heavy black/wet carbon deposits compared to other cylinders if the injector is leaking.
4
Remove the cylinder 2 injector and test on a flow bench for static leakage rate (no electrical energization); any measurable flow confirms the leak.
5
Verify fuel system pressure is within specification using a fuel pressure gauge; excessive pressure (above spec) can exacerbate injector leakage.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The ECM has detected that the fuel injector on cylinder 2 is leaking, allowing fuel to enter the combustion chamber when the injector should be closed. This is identified through individual cylinder fuel trim analysis showing persistent maximum negative fuel correction on cylinder 2. The driver may ...
The most common cause of P02A1 (Cylinder 2 - Injector Leaking) is: Worn or damaged injector pintle or seat on cylinder 2, allowing fuel to drip past when de-energized
Typical repair costs for P02A1 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A leaking injector poses a fire risk from fuel accumulation and can cause hydro-lock if sufficient fuel pools in the cylinder during extended engine-off periods. It also accelerates cylinder wall and ring wear by washing away lubricating oil. Repair promptly and do not leave the vehicle parked for extended periods with residual fuel pressure.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02A1 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Generic (SAE)
Recommended Tools
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