What Does P1233 Mean?
DTC P1233 indicates the turbocharger wastegate has failed in the open position, resulting in under-boost conditions. The PCM has detected that actual boost pressure is consistently below the commanded target, meaning the wastegate valve is not closing to allow the turbocharger to build adequate pressure. This results in significantly reduced engine performance and power output.
Common Causes
30%
Wastegate actuator diaphragm ruptured or spring broken
25%
Wastegate valve stuck open due to carbon buildup or mechanical binding
20%
Vacuum/boost leak in the wastegate actuator supply hose
15%
Faulty wastegate control solenoid not routing vacuum/pressure correctly
10%
Wastegate linkage disconnected or out of adjustment
Diagnostic Steps
1
Monitor actual boost pressure vs. desired boost pressure with a scan tool during a loaded acceleration — a large deficit confirms under-boost.
2
Visually inspect the wastegate actuator rod and linkage for disconnection, binding, or damage. Try moving the wastegate valve by hand with the engine off to check for free movement.
3
Apply vacuum/pressure directly to the wastegate actuator with a hand pump to verify the diaphragm holds and the valve moves fully through its range.
4
Inspect all boost-side hoses and connections from the turbo outlet to the intake manifold for leaks that could prevent boost buildup.
5
Check the wastegate control solenoid by commanding it on/off with a scan tool and verifying it clicks and passes air appropriately.
Estimated Repair Cost
$200 - $1,200
Parts + labor, varies by vehicle and location
DTC P1233 indicates the turbocharger wastegate has failed in the open position, resulting in under-boost conditions. The PCM has detected that actual boost pressure is consistently below the commanded target, meaning the wastegate valve is not closing to allow the turbocharger to build adequate pres...
The most common cause of P1233 (Wastegate Failed Open (Under Pressure)) is: Wastegate actuator diaphragm ruptured or spring broken
Typical repair costs for P1233 range from $200 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
While an open wastegate is safer than a closed one (no over-boost risk), the significant loss of power can be hazardous during highway merging or overtaking maneuvers where expected acceleration is not available.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1233 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Powertrain
System
Turbocharger / Boost Control
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
