TSB's

Chevy refuses to shift

This TSB applies to 2009 Chevy Traverse vehicles (but may also apply to a number of other GM models). The MIL is on and the transmission does not shift through all of the gears. A DTC P182E is set in the transmission control module.

Make a quick check of the engine wiring harness for chafing at the front cylinder head machined surface for the valve cover. If the ECM P/N circuit 1786 is intermittently grounded (when the transmission is in Drive), this code will sset, possible with additional DTCs. If the harness is not chafed, see the following procedure:

  1. Clear the DTC.
  2. Adjust the shift cable per the service manual.
  3. Check the shifter and cable for proper movement with no sticking or escessive effort to move the shifter through all detents. Correct as needed.
  4. Connect a scan tool.
  5. Start the engine, set the emergency brake and apply the brake pedal. Make 10 sets of shifts from Park to Reverse and Reverse to Park. Shift the shifter through all quadrants Park to Lo/M and back to Park, 5 times. If DTC P182E set again, refer to the service manual and complete diagnostics. If the DTC did not set again, shift through each shift quadrant while observing Mode Switch (IMS) on the scan tool. If switch circuits A/B/C/P change correctly, return the vehicle to the customer.

SCAN TOOL DATA

IMS A/B/C/P circuit       Signal A           Signal B           Signal C           Signal P

Park………………………LOW….......………HI…………....…HI………………..LOW

Reverse…………………..LOW……….......…LOW……...…...HI………………..HI

Neutral……………………HI……………........LOW………...…HI………………..LOW

Drive……………………..HI…………….........LOW………......LOW…………….HI

Tags: Chevrolet  GM  transmission 
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