What Does P1091 Mean?
The tumble generator valve on the right bank is stuck in the closed position. This valve should open at higher RPM to maximize airflow but cannot move to the fully open position, restricting engine breathing.
Common Causes
40%
Carbon buildup or debris preventing valve from opening
30%
Failed tumble valve actuator motor or solenoid
15%
Seized valve shaft or binding linkage
10%
Vacuum actuator diaphragm failure or vacuum leak
5%
Faulty valve position sensor providing incorrect feedback
Diagnostic Steps
1
Step 1: Attempt to manually move tumble valve to check for binding or seizure
2
Step 2: Use scan tool to command valve actuation and observe valve movement
3
Step 3: Test actuator motor electrical circuit and motor operation
4
Step 4: Inspect for carbon deposits and check valve shaft for corrosion
5
Step 5: If vacuum-operated, test vacuum supply and actuator diaphragm integrity
Estimated Repair Cost
$250 - $700
Parts + labor, varies by vehicle and location
The tumble generator valve on the right bank is stuck in the closed position. This valve should open at higher RPM to maximize airflow but cannot move to the fully open position, restricting engine breathing.
The most common cause of P1091 (Tumble generator valve #1 (RH) malfunction (stuck close)) is: Carbon buildup or debris preventing valve from opening
Typical repair costs for P1091 range from $250 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive but may experience reduced power at higher RPM and decreased fuel economy. Restricted airflow can cause engine to run rich under load.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1091 to identify the root cause.
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Quick Info
Category
Powertrain
System
Air Intake and Engine Performance
Difficulty
Type
Manufacturer
Recommended Tools
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