Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
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Hello, Can I ask if you are pulling a fault code and if so... which code?
Also the last eight of your vin would be helpful to pull up warranty information.
Here is your warranties while I'm still looking...
I don't want to jump the gun not knowing the fault code but based on the only info I have at this point you may have a software fix for your vehicle...
This bulletin is being revised to update the reprogramming emission controller warranty coverage period information. Please discard Corporate Bulletin Number 09-06-04-022A (Section 06 -- Engine/Propulsion System).
Some customers may comment that the malfunction indicator lamp (MIL) is illuminated, or it illuminates intermittently.
The technician may find DTC P0191 set as current or in history.
Verify the model year of the vehicle in order to determine which one or both of the following procedures to utilize.
For 2006-2008 Vehicles - Diagnose Possible Slow Fuel Rail Pressure Decay First
Important: DO NOT replace the ECM, the fuel rail pressure regulator, or the fuel rail pressure sensor for this condition.
If the Fuel Rail Pressure Sensor parameter is more than the specified value within the specified time period, then reprogram the ECM.
Important: If a 2006-2007 LLY, LBZ vehicle has, as one of nine ECM module ID Part Numbers, Part Number 12632483, then reprogramming the ECM will not repair this condition. If a 2007i-2008 LMM vehicle had field action V1819 - 08142 ECM EEPROM - REPROGRAM ECM applied, then reprogramming the ECM will not repair this condition. All 2009 LMM's already have an extended rail pressure bleed down calibration.
A revised software calibration has been released to address this condition. Reprogram the ECM using the Service Programming System (SPS) with the latest calibration available on TIS2WEB. Refer to the SPS procedures in SI.
When using a multiple diagnostic interface (MDI) for reprogramming, ensure that it is updated with the latest software version.
When using a Tech 2® for reprogramming, ensure that it is updated with the latest software version.
During programming, the battery voltage must be maintained within the proper range of 12-15 Volts. Only use the approved Midtronics® PSC 550 Battery Maintainer (SPS Programming Support Tool EL-49642) or equivalent during programming.
For 2006-2009 Vehicles - Use The Following Testing Procedures
A secondary cause of DTC P0191 may result from a poor connection at the pigtail connector, or the engine harness connector, incorrect crimps, corrosion, and/or poor terminal tension.
Voltage fluctuations at key up, which false trigger a DTC P0191 can be very brief (less than 1 second) and may occur due to any aftermarket equipment installed on the vehicle.
Important: Aftermarket electrical equipment should have a diode connected across the power circuit (coil side) of the relay or solenoid being used in order to prevent transient voltage spikes. For more information on this subject, refer to Corporate Bulletin Number 08-08-45-004A.
Inspect for the proper installation and operation of any aftermarket equipment that may interrupt/interfere with the ignition voltage to the ECM. Refer to Checking Aftermarket Accessories in SI.
The following list is an indication of some of the types of aftermarket equipment that upfitters install.