Silverado Classic 1500 4WD V8-4.8L (2007)
HISTORY DTC
If all readings are normal per Step 2 above, capture and record Freeze Frame/Failure Data, clear DTCs and attempt to duplicate the fail conditions.
1. If the DTC does not reset and the original freeze frame data reports an IMS A/B/C/P code of "HLLL" and the IMS state of "Neutral/Drive 6",
complete the following:
Important
Typical Freeze Frame operating conditions: ISS >500 RPM, OSS =0 RPM or low value, Engine Torque >30 Nm.
Important
There is no calibration update for vehicles equipped with a 6L90 RPO MYD transmission or 2008 model year vehicles. These
calibrations were updated before production began.
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Update the TCM calibration file to the latest released on TIS2WEB.
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Inspect the shift cable for incorrect routing, kinks, severe bends and/or a damaged or twisted rubber boot at the transmission end of the cable.
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Check and ensure proper cable adjustment.
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Determine if the shift lever can be hung-up between Neutral and Drive 6. If so, there may be excessive drag in the system.
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Move the shift lever through each detent position, ensuring positive detent feel. If any concern is noted, remove the transmission oil pan and
repeat the shift lever movement. Ensure that the detent spring roller moves to the bottom of the valley on the detent plate for each shift lever
position. Inspect the detent spring roller and ensure it is centered on the detent plate. The spring arms should not be rubbing on either the IMS
arm or detent plate.
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After completing the above steps, test drive the vehicle, moving the shifter through all detent positions. If no issues are found, ensure all DTC
codes are cleared from history and return the vehicle to the customer. If the vehicle has been returned to the dealer with this Freeze Frame bit
codes after repairs, contact the person(s) below in Step 4.
2. If the DTC does not reset and original freeze frame data reports an IMS A/B/C/P code of "HHLH" and IMS state of "Blank", complete the
following:
Important
Typical Freeze Frame operating conditions: ISS >500 RPM, OSS >0 RPM, Vehicle Speed >0 MPH
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Replace the Internal Mode Switch (IMS) if the Vehicle Build Date is prior to March 31, 2007. If not, continue with this bulletin.
Important
There is no calibration update for vehicles equipped with a 6L90 RPO MYD transmission or 2008 model year vehicles. These
calibrations were updated before production began.
-
Update the TCM calibration file to the latest released on TIS2WEB.
-
After completing the above steps, test drive the vehicle, moving the shifter through all detent positions. If no issues are found, ensure all DTC
codes are cleared from history and return the vehicle to the customer.
3. If the DTC does not reset and original freeze frame data reports an IMS A/B/C/P code of "HHHL" and IMS state of "Invalid", complete the
