What Does P02B5 Mean?
The ECM has detected that the fuel injector on cylinder 7 is leaking fuel, allowing unmetered fuel into the combustion chamber or intake manifold when the injector should be fully closed. This creates an overly rich condition specifically on cylinder 7. The driver may notice rough idle, black exhaust smoke, fuel smell, poor fuel economy, and possible misfires on that cylinder.
Common Causes
35%
Worn or damaged injector pintle seal or O-ring allowing fuel seepage when the injector is closed
25%
Cracked or scored injector nozzle seat preventing complete fuel shutoff
20%
Contaminated or corroded injector internals causing the needle valve to stick partially open
12%
Excessive fuel system pressure forcing fuel past the injector seal during closed periods
8%
Faulty injector driver circuit holding the injector partially energized when it should be fully closed
Diagnostic Steps
1
Monitor cylinder 7 short-term and long-term fuel trim values via live data — a significantly negative trim (below -10%) confirms the ECM is compensating for a rich condition from the injector leak.
2
Perform a fuel injector balance test or cylinder power contribution test to compare cylinder 7 against the other cylinders.
3
Check fuel system pressure: key-on engine-off should hold at specified rail pressure (typically 55-62 PSI). Monitor bleed-down rate after shutoff — rapid decay points to a leaking injector or check valve.
4
Remove the fuel rail with injectors (engine off, pressure relieved) and apply regulated pressure while watching each injector tip for dripping — no more than 1 drop per minute.
5
Inspect the cylinder 7 spark plug for heavy black carbon fouling or wet fuel deposits confirming unmetered fuel entry.
Estimated Repair Cost
$150 - $450
Parts + labor, varies by vehicle and location
The ECM has detected that the fuel injector on cylinder 7 is leaking fuel, allowing unmetered fuel into the combustion chamber or intake manifold when the injector should be fully closed. This creates an overly rich condition specifically on cylinder 7. The driver may notice rough idle, black exhaus...
The most common cause of P02B5 (Cylinder 7 - Injector Leaking) is: Worn or damaged injector pintle seal or O-ring allowing fuel seepage when the injector is closed
Typical repair costs for P02B5 range from $150 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Driveable short distances but repair soon. A leaking injector washes oil from cylinder walls causing accelerated wear, overloads the catalytic converter with unburned fuel, and in severe cases creates a fire risk from raw fuel in the exhaust.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02B5 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
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