FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Buick >> 2013 >> Verano L4-2.0L Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0826

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

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. The TCM will not allow a downshift if the engine would be compromised by overspeeding.

Conditions for Running the DTC

P0815 or P0816

* DTC P0815, P0816, P0826, P1761, P182E, P1876, P1877, or P1915 is not set.

* Engine speed is 400-7,500 RPM for 5 s.

* Ignition voltage is 9-32 V.

* Time since the last gear range change is 1 s or greater.

* DTC runs continuously when the above conditions are met.

P0826

* DTC P0826 or P1761 is not set.

* Engine speed is 400-7,500 RPM for 5 s.

* Ignition voltage is 9-32 V.

* DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0815 - Condition 1

Transmission control module (TCM) detects an upshift request for 1 s with the shift lever in Park or Neutral.

P0815 - Condition 2

TCM detects an upshift request for 10 min with the shift lever in a forward range.

P0816 - Condition 1

TCM detects a downshift request for 1 s with the shift lever in Park or Neutral.

P0816 - Condition 2

TCM detects a downshift request for 10 min with the shift lever in a forward range.

P0826

TCM detects an invalid voltage on the Tap Up/Down signal circuit for 1 min.

Action Taken When the DTC Sets

* P0815, P0816, and P0826 are Type C DTCs.

* TCM inhibits Tap Up/Down function.

Conditions for Clearing the DTC

P0815, P0816, and P0826 are Type C DTCs.

Diagnostic Aids

A high resistance in the signal circuit may not set a DTC. Symptoms could include an inoperative manual mode Tap Up/Down, or a Tap Down shift when the Tap/Up button is pressed.

If battery positive voltage is not present at the shift selector lever, it will not cause a DTC to set, but will result in an inoperative manual mode Tap Up/Down.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics Electrical Diagrams

Connector End View Reference

* Component Connector End Views Outside Rearview Mirror - Driver

* Inline Harness Connector End Views X100

Description and Operation

* Transmission General Description Transmission General Description

* Transmission Component and System Description Transmission Component and System Description

* Electronic Component Description Electronic Component 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.


Note: The engine may have to be started to move the shift lever out of the Park position. Once out of the Park position, the engine can be turned OFF.

1. Verify DTC P182E or P1915 was not set by reviewing the scan tool Freeze Frame/Failure Records.

• If DTC P182E or P1915 was set
Refer to DTC P182E or P1915 P182E.

• If DTC P182E or P1915 was not set

2. Ignition ON, engine OFF.

3. Verify the scan Driver Shift Control Mode parameter displays Inactive with the shift lever in the Park, Reverse, Neutral and Drive positions, and Active when the shift lever is left of the Drive position.

• If the parameter does not display the correct values
Refer to Circuit/System Testing.

• If the parameter displays the correct value

4. Shift lever left of the D position.

5. 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 gear shift lever is pressed rearward.

• If the parameter does not display the correct values
Refer to Circuit/System Testing.

• If the parameter displays the correct value

6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

7. Verify the DTC does not set.

• If the DTC sets
Refer to Circuit/System Testing.

• If the DTC does not set

8. All OK.

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 vehicle harness connector ground circuit 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 11-13 V at the vehicle harness connector between signal circuit terminal 3 and ground.

• If not between 11-13 V

1. Ignition OFF, disconnect the connector at the BCM.

2. Test for infinite resistance between the signal circuit 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 BCM.

• If between 11-13 V

5. Ignition OFF, connect the harness connector at the S3 Transmission Shift Lever, ignition ON.

6. Test for voltage between the S3 Transmission Shift Lever connector signal circuit terminal 3 and ground, by back probing the connector, for the conditions listed below.

* 2.0-4.6 V - Shift lever left of D, pressed forward

* 5.1-7.3 V - Shift lever left of D, pressed rearward

* 8.0-10.6 V - Shift lever left of D

* 11-13 V - Shift lever in D

• If voltage values are not correct
Replace the S3 Transmission Shift Lever.

• If voltage values are correct

7. Replace the K9 Body Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic repair.

* Transmission Control Replacement Transmission Control Replacement for Transmission Shift Lever replacement.

* Control Module References Control Module References for BCM replacement, programming and setup.

pro multis Credits:Operation CHARM About Operation CHARM