i've seen old posts refer to a special function to relearn and clear DBW throttle settings, but it doesn't appear in the latest version of VCM Scanner? i have a Gen3 TBSS throttle body that clatters for a few seconds when i turn the ignition on. was told i needed to perform a relearn procedure?
Year/make/model, please, of the OS in the PCM/ECM. A real TBSS is Gen 4. Real unclear what systems you are working with here, and that makes it real hard to go look up something for you in the factory service manuals.
Originally Posted by SiriusC1024
homemade racecar, using a P59 with a 2004 CTS base file. 5.3L with the Trailblazer intake and a CTS TAC & pedal.
OS 1259618
Attachment 160043
Well, hate to tell you, but the thing you've built doesn't exist in the manuals (8-wire TAC running a 6-wire throttle body). You get to figure out how/if it works and then see if you can reverse engineer a workable relearn strategy.
This is from a later (real) Gen 4, just for background info... there is no procedure listed for 2004 CTS-V.
Conditions for Running the Throttle Learn Procedure
Without Scan Tool - Learn Procedure
- DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0122, P0123, P0128, P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0220, P0222, P0223, P0300, P0351, P0352, P0353, P0496, P0601, P0604, P0606, P060D, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128, P2135, P2138, or P2176 are not set.
- The engine speed is between 450-4,000 RPM.
- The manifold absolute pressure (MAP) is greater than 5 kPa.
- The mass air flow (MAF) is greater than 2 g/s.
- The ignition 1 voltage is greater than 10 volts.
(NOTE this means if there is no MAF, throttle learn will not ever work)
Throttle Learn
Without Scan Tool - Learn Procedure
Important: Do NOT perform this procedure if DTCs are set. Refer to Diagnostic Trouble Code (DTC) List - Vehicle.
Start and idle the engine in PARK for 3 minutes.
With a scan tool, monitor desired and actual RPM.
The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
Ignition OFF for 60 seconds.
Start and idle the engine in PARK for 3 minutes.
After the 3 minute run time the engine should be idling normal.
Important: During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn.
- If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.
After the drive cycle, the engine should be idling normally.
- If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds and repeat step 6.
Once the engine speed has returned to normal, clear DTCs and return to the diagnostic that referred you here.
thank you for the info.
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