P0826
DTC P0815, P0816, or P0826
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructionsprovides an overview of each diagnostic category.
DTC Descriptors
DTC P0815
- Upshift Switch Circuit
DTC P0816
- Downshift Switch Circuit
DTC P0826
- Up and Down Shift Switch Circuit
Diagnostic Fault Information
Circuit/System Description
The driver shift control, also known as the TAP Shift, allows the driver to manually shift transmission modes and gears by pressing the Plus/Minus button to select the desired range of gears for your current driving conditions by using the driver shift control shift switch located on the automatic transmission gear shift lever. Pushing the Plus switch will command an upshift and pushing the Minus switch will command a downshift. 12 V reference voltage flows from the ignition body control module (BCM) through the driver shift control switch resistor array to the BCM. The driver shift control shift system is activated when the gear selector is in the Manual (M) position. The driver shift control system is deactivated in all other range positions.
Conditions for Running the DTC
* The engine speed is 500-6,500 RPM for at least 5 seconds.
* No DTC P0826.
* The vehicle speed is less than 200 km/h (124 mph) for 5 seconds.
* The transmission fluid temperature is -59 to +159°C (-74 to +318°F).
* The system voltage is 11-18 V.
Conditions for Setting the DTC
P0815
The BCM detects an upshift request for 3 seconds when the transmission range selector is in D or 600 seconds in P, R, or N.
P0816
The BCM detects a downshift request for 3 seconds when the transmission range selector is in D or 600 seconds in P, R, or N.
P0826
The BCM detects an invalid voltage from the automatic transmission manual shift switch for 5 seconds.
Action Taken When the DTC Sets
* P0815, P0816, and P0826 are Type C DTCs.
* The BCM disables driver shift control operation.
Conditions for Clearing the DTC
P0815, P0816, and P0826 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics 2ML70 - Automatic Transmission
Connector End View Reference
Component Connector End Views Connector End Views By Name
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Programming and Relearningfor scan tool information.
Circuit/System Verification
Ignition ON, observe the scan tool Driver Shift Request parameter while toggling between the up shift and down shift with the driver manual shift switches. The reading should change between Upshift and Downshift.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the S2 transmission manual shift switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
3. Verify the scan tool Driver Shift Request parameter is Invalid.
• If not the specified value, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the K9 BCM.
4. Install a 6.5-7.0 K ohm jumper wire between the signal circuit terminal 3 and the B+ circuit terminal 4. Verify the scan tool Driver Shift Request parameter is None.
• If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, test or replace the S2 transmission manual shift switch.
Component Testing
1. Ignition OFF, disconnect the harness connector at the S2 transmission manual shift switch.
2. Test for 6.5-7.0K ohm between the signal terminal 3 and the B+ terminal 4 with the switch in the released position.
• If not the specified value, replace the S2 transmission manual shift switch.
3. Test for 1.5-2.0K ohm between the signal terminal 3 and the B+ terminal 4 with the switch in the plus position.
• If greater than the specified range, replace the S2 transmission manual shift switch.
4. Test for 3.8-4.0K ohm between the signal terminal 3 and the B+ terminal 4 with the switch in the minus position.
• If greater than the specified range, replace the S2 transmission manual shift switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Shift Lever Replacement Shift Lever Replacementfor Transmission Manual Shift Switch replacement.
* Control Module References Programming and Relearningfor Body Control Module replacement, programming and setup.