P0826-UP/DOWN SHIFT SWITCH CIRCUIT

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

The AutoStick function allows the driver to manually change the gear ratio to a locked ratio. The Transmission Control Module (TCM) monitors the AutoStick Upshift and Downshift circuits. If the TCM receives an Upshift and Downshift request simultaneously, or manual mode Upshift/Downshift request while other than in the D-Range, a DTC will set.

When Monitored:
Ignition on with a system voltage between 9.0 and 16 volts.
Set Condition:
Upshift and Downshift requested simultaneously while in the Drive position or the Upshift and/or Downshift request during while not in the Drive position for the period of 1.0 second.

Possible Causes

(T5) AUTOSTICK UPSHIFT SWITCH SIGNAL CIRCUIT SHORT TO GROUND

(T44) AUTOSTICK DOWNSHIFT SWITCH SIGNAL CIRCUIT SHORT TO GROUND

SHIFT LEVER ASSEMBLY

TRANSMISSION CONTROL MODULE

Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

Diagnostic Test

1. CHECK IF THE DTC IS ACTIVE

With the scan tool, erase Transmission DTCs.
Start the engine, with the brakes firmly applied shift the shift lever into Drive and make several AutoStick upshifts and downshifts.
With the scan tool, read Transmission DTCs.

Is the status Active for this DTC or is the STARTS SINCE SET counter 2 or less?

Yes

Go To 2

Go To 7

2. VERIFY PROBLEM

With the scan tool, read the AutoStick upshift and downshift status.

Does the scan tool show either the upshift or downshift as true with the shifter in the center position (pick best answer)?

Upshift shows as true

Go To 3

Downshift shows as true

Go To 5

Neither circuit shows as true

Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins for possible causes that may apply. If no problems are found, replace the TCM per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

3. CHECK THE SHIFT LEVER ASSEMBLY

Turn the ignition off to the lock position.
Disconnect the Shift Lever Assembly harness connector.
Ignition on, engine not running.
With the scan tool read the AutoStick Upshift status.

Does the Upshift still show as true?

Yes

Go To 4

Replace the Shift Lever Assembly per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

4. CHECK THE (T5) AUTOSTICK UPSHIFT SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Measure the resistance between ground and the (T5) AutoStick Upshift Switch Signal circuit.

Is the resistance below 5.0 ohms?

Yes

Repair the (T5) AutoStick Upshift Switch Signal circuit for a short to ground.

Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins for possible causes that may apply. If no problems are found, replace the TCM per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

5. CHECK THE SHIFT LEVER ASSEMBLY

Turn the ignition off to the lock position.
Disconnect the Shift Lever Assembly harness connector.
Ignition on, engine not running.
With the scan tool read the AutoStick Downshift status.

Does the Downshift still show as true?

Yes

Go To 6

Replace the Shift Lever Assembly per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

6. CHECK THE (T44) AUTOSTICK DOWNSHIFT SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND

Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Measure the resistance between ground and the (T44) AutoStick Downshift Switch Signal circuit.

Is the resistance below 5.0 ohms?

Yes

Repair the (T44) AutoStick Downshift Switch Signal circuit for a short to ground.

Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for any Service Bulletins for possible causes that may apply. If no problems are found, replace the TCM per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

7. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits.

Were there any problems found?

Yes

Repair as necessary.

Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

Test Complete.