P0816
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
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
When the shift lever is moved left of the D position, the transmission will enter sport mode. With the shift lever in this position, the transmission will enter manual mode if the gear shift lever is pressed forward or rearward. This allows the operator to select an upshift by pressing the gear shift lever forward, and downshift by pressing the gear shift lever rearward. The Body Control Module (BCM) supplies an ignition circuit and a signal circuit to the shift controller. The shift controller has Hall-effect switches connected to a resistor array. When the lever is left of the D position, a voltage drop occurs across the resistor network. When the gear shift lever is pressed forward or rearward, 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
* DTC P0826, P1761, P182E, P1876, P1877, or P1915 is not set.
* Time since the range change is 1 s or greater.
* Engine speed is 400 RPM or greater for 5 s.
* Ignition voltage is 8.6 volts or greater.
P0826
* Engine speed is 400 RPM or greater for 5 seconds.
* Ignition voltage is 8.6 volts or greater.
* DTC P1761 is not set.
Conditions for Setting the DTC
P0815 - Condition 1
TCM detects an upshift request for 1 second in Park or Neutral.
P0815 - Condition 2
TCM detects an upshift request for 10 minutes in any forward range.
P0816 - Condition 1
TCM detects a downshift request for 1 second in Park or Neutral.
P0816 - Condition 2
TCM detects a downshift request for 10 minutes in any forward range.
P0826
TCM detects an invalid voltage on the Tap up/Tap down signal circuit for 1 minute.
Action Taken When the DTC Sets
* DTCs P0815, P0816, and P0826 are Type C DTCs.
* TCM inhibits Tap Up/Down function.
* TCM inhibits manual shifting of forward gears.
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 A/C Compressor Clutch
* Inline Harness Connector End Views X100
Description and Operation
Transmission General Description Transmission General 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, engine OFF.
2. Verify with a scan tool 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 are not set
3. Verify with a scan tool the Driver Shift Control Mode parameter displays Inactive with the shift lever in the Park, Reverse, Neutral, and Drive positions, and Active with the gear shift lever left of the D position.
• If the parameter does not display the correct values
Refer to Circuit/System Testing
below.
• If the parameter displays the correct value
4. Shift lever left of the D position, verify the scan tool Driver Shift Request parameter changes from None to Upshift when the shift lever is pressed forward, and from None to Downshift when the shift lever is pressed rearward.
• If the parameter does not display the correct values
Refer to Circuit/System Testing
below.
• If the parameter displays the correct value
5. 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
Note: You must perform the Circuit/System Verification first.
1. Ignition OFF, disconnect the harness connector from the S3 Transmission Shift Lever.
2. Test for less than 10 ohms between the 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. Verify a test lamp illuminates between the S3 Transmission Shift Lever harness connector ignition circuit terminal 1 and ground circuit terminal 2.
• If the test lamp does not illuminate
1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
2. Test for less than 2 ohms in the ignition circuit end to end.
• If 2 ohms or greater, repair the ignition circuit.
• If less than 2 ohms, replace the K9 Body Control Module.
• If the test lamp illuminates
5. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
6. 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
7. 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
8. Connect the K9 Body Control Module harness connector, ignition ON.
9. Verify the scan tool Driver Shift Control parameter displays inactive.
• If Driver Shift Control Mode Parameter does not display Inactive
Replace the K9 Body
Control Module.
• If Driver Shift Control Parameter displays Inactive
10. Test for 11-13 volts at the S3 Transmission Shift Lever harness connector between signal circuit terminal 3 and ground.
• If not between 11-13 volts
Replace the K9 Body Control Module.
• If between 11-13 volts
11. Ignition OFF, connect the S3 Transmission Shift Lever harness connector, Ignition ON.
12. Test for 11-13 volts by back probing the transmission shift lever connector between terminal 3 and ground with the shift lever in Park, Reverse, Neutral, and Drive.
• If not between 11-13 volts
Replace the S3 Transmission Shift Lever.
• If between 11-13 volts
13. Shift Lever left of D position
14. Test for 8.0-10.6 volts between S3 Transmission Shift Lever connector terminal 3 and ground.
• If not between 8.0-10.6 volts
Replace the S3 Transmission Shift Lever.
• If between 8.0-10.6 volts
15. Test for 5.1-7.3 volts between S3 Transmission Shift Lever connector terminal 3 and ground with the shift lever pressed rearward.
• If not between 5.1-7.3 volts
Replace the S3 Transmission Shift Lever.
• If between 5.1-7.3 volts
16. Test for 2.0-4.6 volts between S3 Transmission Shift Lever connector terminal 3 and ground with the shift lever pressed forward.
• If not between 2.0-4.6 volts
Replace the S3 Transmission Shift Lever.
• If between 2.0-4.6 volts
17. Replace the K9 Body Control Module.
Repair Instructions
Note:
* Perform the Reset Transmission Adapts Reset Procedure following all transmission related repairs.
* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Control Module References Control Module References for BCM or control solenoid valve assembly replacement, setup and programming
* Transmission Control Replacement (Acadia) Transmission Control Replacement