Diagnostic Instructions
DTC Descriptor
DTC P0815 00: Upshift Switch Circuit.
DTC P0816 00: Downshift Switch Circuit.
DTC P0826 00: Up and Down Shift Switch Circuit.
Circuit/System Description
The driver shift control (DSC), also known as the tap shift, allows the driver
to manually shift gears by placing the shift control lever in the DSC position and
pushing the lever upwards or downwards to select the desired gear. The DSC receives
a 12 volt supply voltage from the BCM, and when pushing the shift lever in either
direction a momentary switch is activated and a signal is sent to the cruise control
module and body control module (BCM). The DSC shift system is only activate when the
gear selector is in the Manual (M) position. The DSC system is deactivated in all
other range positions.
Conditions for Running the DTC
DTCs P0815, P0816 or P0826
| • | The engine speed is between 500-6,500 RPM for at least 5 seconds. |
| • | The time since the last gear selector range change is greater than 6 seconds. |
Conditions for Setting the DTC
DTC P0815
The BCM detects an upshift request for 3 seconds in PARK, REVERSE, NEUTRAL,
or D6- and for 600 seconds in PARK, REVERSE, NEUTRAL, D2, D4, OR D6.
DTC P0816
The BCM detects a downshift request for 3 seconds in PARK, REVERSE, NEUTRAL,
or D6- and for 600 seconds in PARK, REVERSE, NEUTRAL, D2, D4, or D6.
DTC P0826
The BCM detects an invalid voltage on the TAP up/down signal circuit for 5 seconds.
Action Taken When the DTC Sets
The multi function display (MFD) displays the ESP Off message.
| • | DTCs P0815, P0816, and P0826 are Type C DTCs. |
| • | The BCM disables TAP shift operation. |
Conditions for Clearing the DTC
DTCs P0815, P0816, and P0826 are Type C DTCs.
Reference Information
Schematic Reference
Antilock Brake System Schematics
.
Connector End View Reference
Component Connector End Views
.
Electrical Information Reference
Scan Tool Reference
Control Module References
.
Circuit/System Verification
With the engine ON, engage the DSC switch positions. using a scan too while
observe the Driver Shift Request parameter. The parameter should change to reflect
the selected up or downshift switch position and with no up or downshift switch position
selected the parameter should display None.
Circuit/System Testing
DTC P0815
- Select the Driver Shift Request parameter.
- Disconnect the automatic transmission DSC shift switch connector.
| ⇒ | If the parameter status changes from upshift to invalid, replace the DSC shift
switch. |
| ⇒ | If the parameter status does not change, replace the BCM. |
DTC P0816
- Select the Driver Shift Request parameter.
- Disconnect the DSC shift switch connector.
| ⇒ | If the parameter status changes from downshift to invalid, replace the DSC shift
switch. |
| ⇒ | If the parameter status does not change, replace the BCM. |
DTC P0826
- If any other DTC are set diagnose those DTCs first.
- Ignition OFF, disconnect the DSC shift switch connector.
- Connect a test lamp between the 12 V reference and a known ground.
| ⇒ | If the test lamp does not illuminate, test the 12 V reference circuit
for an short to ground or open/high resistance. If circuit test normal replace the
BCM. |
- If all circuits test normal replace the electronic range selector switch.
Component Testing
- Test the DSC shift switch for correct resistance value, 8.11-8.39 ohms.
| ⇒ | If the resistance is not within specifications, replace the DSC switch. |
Repair Instructions
Perform the
Diagnostic Repair Verification
Diagnostic Repair Verification after completing the diagnostic procedure.
