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 Instructions provides 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
Typical Scan Tool Data
Circuit/System Description
When the shift lever is placed in manual mode (M), the driver shift request (DSR), also known as the tap shift function is activated. The DSR allows the vehicle operator to shift gears by pushing the plus (+) button for an upshift or minus (-) button for a downshift. The body control module (BCM) supplies a signal circuit to the shift controller. The shift controller has switches connected to a resistor array. When the lever is in the M position, a voltage drop occurs across the resistor network. When the plus or minus button is pushed, a corresponding voltage drop occurs across the resistor network. This voltage drop is monitored by the BCM. The BCM will send the request to the transmission control module to perform the upshift or downshift.
Conditions for Running the DTC
P0815 or P0816
* Engine speed is 400 RPM or greater for 5 seconds.
* Ignition voltage is 9.0 V or greater.
* DTC P0815, P0816, P0826, P1761, P182E, P1876, P1877, or P1915 is not set.
* Time since the last gear range change is greater than 1 second.
P0826
* Engine speed is 400 RPM or greater for 5 seconds.
* Ignition voltage is 9.0 V or greater.
* DTC P0826 or P1761 is not set.
Conditions for Setting the DTC
P0815 - Condition 1
Transmission control module (TCM) detects an upshift request for 1 second with the shift lever in PARK, or NEUTRAL.
P0815 - Condition 2
TCM detects an upshift request for 10 minutes with the shift lever in a forward range.
P0816 - Condition 1
TCM detects a downshift request for 1 second with the shift lever in PARK, or NEUTRAL.
P0816 - Condition 2
TCM detects a downshift request for 10 minutes with the shift lever in a forward range.
P0826
TCM detects an invalid voltage on the TAP up/down signal circuit for 1 minute.
Action Taken When the DTC Sets
* DTCs P0815, P0816, and P0826 are Type C DTCs.
* TCM disables TAP shift operation.
Conditions for Clearing the DTC
DTCs P0815, P0816, and P0826 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
* Transmission General Description Transmission General Description
* Transmission Component and System Description Transmission Component and System Description
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 Control Module References for scan tool information
Circuit/System Verification
Warning: Refer to Parking Brake and Drive Wheels Warning Parking Brake and Drive Wheels Warning.
1. Ignition ON.
2. Verify with a scan tool there were no internal mode switch (IMS) DTCs set.
• If IMS DTCs were set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If IMS DTCs were not set
3. Shift lever in the M position, verify the scan tool Driver Shift Request parameter changes from None to Upshift when the plus button is pressed, and from None to Downshift when the minus button is pressed.
• If the parameter does not display the correct values
Refer to Circuit/System Testing below.
• If the parameter displays the correct value
4. After performing the above steps, verify that the DTC does not reset by operating the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions you observe from the Freeze Frame/Failure Records data. If the vehicle passes the Circuit/System Verification procedure, then STOP. Do not perform the Circuit/System Testing or Component Testing as this may result in an unnecessary part replacement. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector from the S3 transmission shift lever.
2. Test for less than 10 ohms between the S3 transmission shift lever harness connector terminal 2 and ground.
• If 10 ohms or greater
Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Test for 11 V or greater at the S3 transmission shift lever harness connector between signal circuit terminal 3 and ground.
• If less than 11 V
1. Ignition OFF, remove the connector at the K9 body control module.
2. Test for infinite resistance between the S3 transmission shift lever harness connector signal circuit terminal 3 and ground.
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance.
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If 11 V or greater
5. Ignition OFF.
6. Test for 5.8-6.4 kohms between the S3 transmission shift lever connector terminal 3 and terminal 2.
• If not between 5.8-6.4 kohms
Replace the S3 transmission shift lever.
• If between 5.8-6.4 kohms
7. Test for 1.8-2.2 kohms between the S3 shift lever connector terminal 3 and terminal 2 with the tap down button depressed.
• If not between 1.8-2.2 kohms
Replace the S3 transmission shift lever.
• If between 1.8-2.2 kohms
8. Test for 580-680 ohms between the S3 shift lever connector terminal 3 and terminal 2 with the tap up button depressed.
• If not between 580-680 ohms
Replace the S3 transmission shift lever.
• If between 580-680 ohms
9. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater
Repair the open/high resistance in the circuit.
• If less than 2 ohms
10. Replace the K9 body control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic repair.
* Refer to Control Module References Control Module References for BCM replacement, programming and setup.
* Refer to Transmission Control Replacement Transmission Control Replacement for AT TAP shift switch replacement.