I have gotten the Overboost code 234 a couple of times, but today I got 238 (Turbocharger Boost Sensor 1 Circuit High Voltage). Does this one mean essentially the same thing as 234? Anything I should worry about?


Mods...Feel free to move this if it is in the wrong forum. I posted here, because only those with tuners would see this code.Edited by: Amric

I can tell you that the PO 234 is Turbo Overboost (I just had that one about 20 minutes agohttp://www.dieselplace.com/forum/smileys/Big Smile.gif) and along with that one I had the PO 700 TCM I reset the 234 with the Predator, but was unable to reset the 700. I then tried it with the Stealth and it reset on the first try.


Even with those two codes I was able to run a 14.13 @ 96.7 (G-Tech Pro) The Track bar and tie rod sleeves make a world of difference on launchhttp://www.dieselplace.com/forum/smileys/Clap.gif 1000rpm, I didn't look at the boost. I still can not break the 2.0 second 60' Mine was 2.01 today. and a 5.87 sec 0-60


Sorry I can not help you on the code. Someome had the full list of codes posted here a few days ago. I am thinking it was J Kennedy.

<H1>DTC P0234 Federal RPO FE9, NG1</H1><A name=ss1-865735><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865735&amp;psdid=437&amp;evc=sm#ss1-865735" target="_blank">
<H5>Circuit Description</A></H5>


The boost sensor responds to pressure changes in the intake manifold. This pressure is created by the turbocharger and changes with accelerator pedal position (APP) and engine speed. The engine control module (ECM) uses this information to assist in diagnosis of the barometric pressure (BARO) sensor and to provide engine overboost protection. The boost sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. The ECM supplies 5 volts to the boost sensor on a 5-volt reference circuit, and provides a ground on a low reference circuit. The boost sensor provides a voltage signal to the ECM on a signal circuit relative to the pressure changes. The ECM monitors the boost sensor signal for voltage outside of the normal range. The ECM calculates a predicted value for the boost sensor. The ECM then compares the predicted value to the actual signal. This DTC will set if the boost sensor signal is above the predicted range.<A name=ss2-865735><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865735&amp;psdid=437&amp;evc=sm#ss2-865735" target="_blank">
<H5>Conditions for Running the DTC</A></H5>
<UL =BULLET>
<LI>DTC P0238 is not set.
<LI>The engine speed is less than 2,700 RPM.
<LI>The fuel quantity is less than 70 mm³.
<LI>The total fuel quantity burned is more than 2,000 mm³. </LI>[/list]<A name=ss3-865735><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865735&amp;psdid=437&amp;evc=sm#ss3-865735" target="_blank">
<H5>Conditions for Setting the DTC</A></H5>


The measured boost pressure is above the expected range by 35 kPa or more for 12 seconds.<A name=ss4-865735><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865735&amp;psdid=437&amp;evc=sm#ss4-865735" target="_blank">
<H5>Action Taken When the DTC Sets</A></H5>
<UL =BULLET>
<LI>The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
<LI>The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
<LI>The ECM limits fuel delivery. </LI>[/list]<A name=ss1-727824><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865735&amp;psdid=437&amp;evc=sm#ss1-727824" target="_blank">
<H5>Conditions for Clearing the MIL/DTC</A></H5>
<UL =BULLET>
<LI>The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
<LI>A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
<LI>A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
<LI>Clear the MIL and the DTC with a scan tool. </LI>[/list]<A name=ss5-865735><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865735&amp;psdid=437&amp;evc=sm#ss5-865735" target="_blank">
<H5>Diagnostic Aids</A></H5>
<UL =BULLET>
<LI>Any changes to the induction system or exhaust system, such as the installation of aftermarket parts, may cause this DTC to set.
<LI>If the condition is intermittent, refer to Intermittent Conditions (http://service.gm.com/servlets/CellHandler?CellId=63696&amp;RefDoc=865735&amp;evc=sm) .</LI>
<LI></LI>[/list]



<H1>DTC P0238 Federal RPO FE9, NG1</H1><A name=ss1-865749><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=865749&amp;psdid=437&amp;evc=sm#ss1-865749" targe

Thanks Diesel Tech....Very good info. So we don't all have to use a calculator like I did, the kPa's are converted as follows:
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">


2 consecutive ignitions at 5psi+ for 12sec+ sets a 234


2 consecutive ignitions at 36.85psi+ for 2sec+ sets a 238</BLOCKQUOTE>


This explains everything. I know I hit 38psi yesturday, but I turned it down, and today the guage only read 34psi, but I guess my guage could be off by 2.85psi. Looks like I've got to turn it down some more.http://www.dieselplace.com/forum/smileys/Cry.gifEdited by: Amric