What Does P0281 Mean?
The ECM has detected a cylinder 7 contribution or balance fault, meaning cylinder 7 is not producing its expected share of engine torque during its power stroke. This is determined by crankshaft speed variation analysis. Found on V8 and larger engines. The driver will notice rough idle, vibration, reduced power, and possible misfire symptoms particularly noticeable at lower engine speeds.
Common Causes
35%
Cylinder 7 fuel injector with degraded flow, restricted nozzle, or sticking
25%
Low compression on cylinder 7 — worn rings, burnt valve, or head gasket failure
20%
Injector circuit wiring or ECM driver issue reducing fuel pulse to cylinder 7
12%
Intake manifold runner restriction or vacuum leak at cylinder 7
8%
Glow plug or ignition component failure on cylinder 7
Diagnostic Steps
1
Monitor live data for cylinder 7 contribution rate and compare it to all other cylinders — on V8 engines, compare particularly to the other cylinders on the same bank.
2
Perform a compression test on all 8 cylinders — cylinder 7 should be within 10% of the highest. Low compression requires a leak-down test to identify the specific failure point.
3
On diesel V8 engines, perform an injector leak-back test — collect return fuel from each injector at idle. Cylinder 7 returning significantly more fuel indicates internal injector wear.
4
Check injection quantity correction values for cylinder 7 in live data — a large positive correction means the ECM is already compensating for a weak injector, confirming the diagnosis.
5
Swap cylinder 7 injector with an adjacent cylinder, clear codes, and drive — this definitively determines whether the injector or the cylinder mechanics are at fault.
Estimated Repair Cost
$150 - $1,500
Parts + labor, varies by vehicle and location
The ECM has detected a cylinder 7 contribution or balance fault, meaning cylinder 7 is not producing its expected share of engine torque during its power stroke. This is determined by crankshaft speed variation analysis. Found on V8 and larger engines. The driver will notice rough idle, vibration, r...
The most common cause of P0281 (Cylinder 7 Contribution/Balance Fault) is: Cylinder 7 fuel injector with degraded flow, restricted nozzle, or sticking
Typical repair costs for P0281 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 at light load for short distances. On V8 engines, a single weak cylinder is less noticeable but still stresses the exhaust aftertreatment. Schedule diagnosis within a few days to prevent secondary damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0281 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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