P1237 Buick Injector Circuit Cylinder 6 Intermittent

P1238 Buick Turbocharger Control valve

Possible causes
– Air leakage after turbocharger
– Hoses between turbocharger and turbocharger control valve are loose, blocked or damage
– Hoses between turbocharger control valve and pressure servo are loose, blocked or damage
– Faulty turbocharger control valve
– Faulty boos pressure control valve pressure servo
– Sticking boost pressure control valve
Tech description
First step is checking for air leak after turbocharger.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P1238 Buick Description

The code O1238 will set if RPM is above 3500 and engine is operating at a high load, control signal to turbocharger control valve is at maximum and boos pressure from boos pressure sensor is lower than approximately 2.9 psi under normal boost pressure (signal too low. If mass from mass air flow sensor is high than desired value (signal too high) it is interpreted as a fault by the Engine Control Module (ECM). When the code is set, a reduce boos pressure is used as a substitute value.

Buick Vehicle:Buick Regal – ?Buick Riviera – ?Buick LaCrosse – ?David Dunbar Buick – Buick Century – Buick LaCrosse – Buick LeSabre – Buick Lucerne – Buick Park Avenue – Buick Regal – Buick Verano – Buick Enclave – Buick Encore – Buick Rainier – Buick Rendezvous – Buick Terraza – Buick Riviera