GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Holden 🢒 2005 🢒 Calais 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 5L40-E/5L50-E 🢒 DTC P0826

Circuit Description

When the 'A/S' momentary contact switch in the centre console is pressed and the 'Active Shift' is enabled, the TAP shift system allows the driver to manually shift gears by using the TAP Shift switches located at the top of the horn bar on the steering wheel. Pushing the '+' (up) switch will command the transmission to upshift and pushing the '-' (down) switch will command a downshift. The TAP shift system is activated when the gear selector is in the D position and is deactivated in all other positions.

If the Transmission Control Module (TCM) detects an invalid voltage on the tap up / tap down switch signal circuit, then P0826 sets, which is a type 'C' DTC.

Conditions for Running the DTC
    • Ignition voltage is between 8.0 and 18.0 volts.
    • Engine speed is between 450 and 6,800 RPM for at least 5 seconds.

Conditions for Setting the DTC

The TCM detects an invalid voltage on the tap up / tap down switch signal circuit for 5 minutes (300 seconds).

Action Taken When the DTC Sets
    • The TCM does not request the Powertrain Interface Module (PIM) to illuminate the Check Powertrain Malfunction Indicator Lamp (MIL).
    • The TCM records the operating conditions when the 'Conditions tor Setting the DTC' are met. The TCM stores this information as a failure record.
    • The TCM disables the TAP shift operation.
    • The TCM stores DTC P0826 in TCM history.

Conditions for Clearing the DTC
    • Tech 2 can clear the DTC.
    • The TCM clears the DTC from its memory (history DTC) if the vehicle completes 40 warm-up cycles without a non-emission related DTC occurring.
    • The TCM cancels the default actions when the ignition is off long enough to power down the TCM.

Test Description

The following number(s) refer to the step number(s) on the diagnostic table.

2. Checks the current state of the Active Select Request circuit.

3. Confirms that an invalid signal has been registered by the TCM.

4. and 5. Checks whether either paddle switch is causing the problem.

7. Checks for a correct value voltage supply to the TCM.

8. and 9. Checks whether either paddle switch has the correct internal resistance.

11-13. Checks the resistance of the paddle switches, as a group and individually.

15. Checks for battery voltage being available at the paddle switches.

16. Checks for and open or short to ground on power circuit 1339.

17. Checks for and open or short to ground on circuit 5526 between the paddle switches and the TCM.

18. Checks for a short to voltage on circuit 5526 between the paddle switches and the TCM.

Step

Action

Values

Yes

No

Schematic Reference: Automatic Transmission Controls Schematics

For information on testing wiring faults, refer to Wiring Systems.

1

Has the Diagnostic System Check - Automatic Transmission been completed?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2
  1. Connect Tech 2 to the DLC.
  2. Ignition ON, engine OFF.
  3. Clear DTC's
  4. Select 'Active Select Request' status on Tech 2.

Does the Tech 2 'Active Select Request' data parameter display 'None' ?

--

Go to Step 4

Go to Step 3

3

Does the Tech 2 'Active Select Request' data parameter display 'Invalid'?

--

Go to Step 6

Go to Step 4

4
  1. Select 'Active Select Request' status on Tech 2.
  2. Press the '-' paddle switch at the steering wheel, hold, then release.

Does the Tech 2 'Active Shift Request' data parameter change from 'None' to 'Shift Down', then back to 'None' ?

--

Go to Step 5

Go to Step 6

5
  1. Select 'Active Select Request' status on Tech 2.
  2. Press the '+' paddle switch at the steering wheel, hold, then release.

Does the Tech 2 'Active Shift Request' data parameter change from 'None' to Shift Up', then back to 'None'?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 6

6
  1. Inspect fuse F32 in the under hood electrical centre X100, for an open (blown) condition.
  2. Replace fuse if necessary.

Was a fuse replacement required?

--

Go to Step 19

Go to Step 7

7
  1. Ignition OFF.
  2. Remove TCM from its cradle. Refer to Transmission Control Module Replacement.
  3. Carefully remove wiring protective cover from the back of TCM connector A112 - T68.
  4. Ignition ON, engine OFF.
  5. With TCM connector A112 - T68 still installed, check voltage between back probed terminal X1-14 and a sound ground, using a digital voltmeter.

Is the voltage check within the specified range?

0.5-0.7 Volts

Go to Step 8

Go to Step 11

8

With voltmeter still connected (as in Step 7), press the '-' paddle switch at the steering wheel and hold.

Is the voltage check within the specified range?

2.8-3.0 Volts

Go to Step 9

Go to Step 11

9

With voltmeter still connected (as in Step 7), press the '+' paddle switch at the steering wheel and hold.

Is the voltage check within the specified range?

1.4-1.6 Volts

Go to Step 10

Go to Step 11

10

Replace TCM. Refer to Transmission Control Module Replacement for replacement procedures.

Is the replacement complete?

--

Go to Step 19

--

11
  1. Remove driver side air bag. Refer to Section 12M Occupant Protection System, for procedure.
  2. Disconnect 4 wire patch harness connector X212 from the paddle switch harness.
  3. Using a digital ohmmeter and appropriate leads from J 35616 , check resistance between X212-1 (Red wire) and X212-2 (Black wire).

Is the resistance check within the specified range?

8.2-8.3 kΩ

Go to Step 12

Go to Step 14

12

With ohmmeter still connected (as in Step 11), press the '-' paddle switch at the steering wheel and hold.

Is the resistance check within the specified range?

1.2-1.3 kΩ

Go to Step 13

Go to Step 14

13

With ohmmeter still connected (as in Step 11), press the '+' paddle switch at the steering wheel and hold.

Is the resistance check within the specified range?

2.8-2.9 kΩ

Go to Step 15

Go to Step 14

14

Replace the automatic transmission shift paddle switches. Refer to Section 9 Steering.

Did you complete the replacement?

--

Go to Step 19

--

15
  1. Disconnect the 4 wire patch harness connector X212.
  2. Ignition ON.
  3. Using a digital voltmeter and appropriate leads from J 35616 , check voltage between X212-1 (White wire) and a sound ground point.

Is the voltage check within the specified range?

Battery Voltage

Go to Step 17

Go to Step 16

16

Using a digital voltmeter and appropriate leads from J 35616-A/BT-8637 Connector Test Adaptor Kit, check for an open or short to ground at X212-1 on power circuit 1339.

Did you find and correct a condition?

--

Go to Step 19

Go to Step 17

17
  1. Ignition OFF.
  2. Disconnect TCM connector A112 - T68.
  3. Using a digital ohmmeter and appropriate leads from J 35616-A/BT-8637 Connector Test Adaptor Kit, check for an open or short to ground in circuit 5526 between TCM connector A112 - T68, terminal X1-14 and paddle switch connector X212, terminal X212-2.

Did you find and correct a condition?

--

Go to Step 19

Go to Step 18

18
  1. Ignition ON.
  2. Using a digital voltmeter, test paddle switch circuit 5526 connector X212-2 (signal circuit) for a short to voltage condition.

Did you find and correct a condition?

--

Go to Step 19

Go to Step 10

19
  1. Perform the following operation to verify the repair.
    2. • Reinstall removed components.
    • Select DTC on Tech 2, then clear DTC.
  2. Operate the vehicle under the following conditions:
    3. • Ignition ON, engine OFF.
    • Observe 'Active Select Request' on Tech 2.
    • Monitor Tech 2 and ensure that the 'Active Select Request' is not displaying 'invalid' for at least 1 second.
    • Operate the '-' paddle switch while monitoring Tech 2 to ensure that the 'Active Select Request' display changes from 'None' to 'Shift Down', then back to 'None' when the paddle switch is released.
    • Operate the '+' paddle switch while monitoring Tech 2 to ensure that the 'Active Select Request' display changes from 'None' to 'Shift Up', then back to 'None' when the paddle switch is released.

Has the test run and passed?

--

System OK

Go to Step 2

When all diagnosis and repairs are completed, clear all DTCs and verify correct operation