P1238 Cadillac Turbocharger Control valve

P1238 Cadillac 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 Cadillac 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.

Cadillac Vehicle:Cadillac CTS Coupe, Cadillac CTS-V Coupe , Cadillac Eldorado , Cadillac Escalade EXT , Cadillac ATS , Cadillac CTS , Cadillac CTS Sedan , Cadillac CTS Sport Sedan , Cadillac CTS-V , Cadillac CTS-V Sedan , Cadillac Catera , Cadillac DTS , Cadillac DeVille , Cadillac STS-V , Cadillac STS , Cadillac Seville , Cadillac XTS , Cadillac XLR , Cadillac XLR Platinum , Cadillac Escalade , Cadillac SRX