What Does P0272 Mean?
The ECM has identified a contribution or balance fault on cylinder 4, meaning this cylinder is not producing its expected share of engine torque. The crankshaft acceleration analysis reveals cylinder 4 is underperforming during its power stroke compared to the other cylinders. The driver will notice rough idle, reduced power, vibration, and possibly increased fuel consumption.
Common Causes
35%
Faulty cylinder 4 fuel injector — restricted flow, poor spray pattern, or sticking
25%
Low compression on cylinder 4 due to valve, ring, or gasket failure
20%
Injector wiring or driver issue reducing fuel delivery to cylinder 4
12%
Carbon buildup or restriction in cylinder 4 intake port
8%
Cylinder 4 glow plug failure (diesel) causing poor combustion initiation
Diagnostic Steps
1
Monitor cylinder 4 contribution rate in live data and compare across all cylinders — note the specific deviation percentage to gauge severity.
2
Perform a compression test on all cylinders — cylinder 4 should read within 10% of the highest. If compression is low, follow up with a leak-down test to identify rings, intake valve, exhaust valve, or head gasket as the leak source.
3
Perform an injector leak-back test on diesel applications — collect return fuel from each injector over 30 seconds at idle. Cylinder 4 should not return significantly more fuel than the others.
4
Check cylinder 4 injector balance by monitoring fuel trim adaptation or injection quantity correction values — excessive correction indicates the ECM is already compensating for a weak injector.
5
Inspect cylinder 4 glow plug (diesel) — measure resistance (typically 0.5-2.0 ohms) and verify heating operation with a thermal camera or current draw test during the preheat cycle.
Estimated Repair Cost
$150 - $1,500
Parts + labor, varies by vehicle and location
The ECM has identified a contribution or balance fault on cylinder 4, meaning this cylinder is not producing its expected share of engine torque. The crankshaft acceleration analysis reveals cylinder 4 is underperforming during its power stroke compared to the other cylinders. The driver will notice...
The most common cause of P0272 (Cylinder 4 Contribution/Balance Fault) is: Faulty cylinder 4 fuel injector — restricted flow, poor spray pattern, or sticking
Typical repair costs for P0272 range from $150 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle can be driven carefully with reduced power. Continued driving with a cylinder imbalance stresses the catalytic converter and can elevate exhaust gas temperatures. Diagnose and repair within a reasonable timeframe to prevent collateral damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0272 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection / Engine Mechanical
Difficulty
Type
Generic (SAE)
Recommended Tools
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