P0957-AUTOSTICK CIRCUIT LOW
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
The AutoStick Switch is located in the Shift Lever Assembly (SLA). The gear requested by the AutoStick selection is then sent over the AutoStick Up/Down sense circuit to the PCM to engage the requested gear. Normal AutoStick® voltages are: Down = 0.71 to 1.11 volts, Up = 2.02 to 2.41 volts.
- When Monitored:
Ignition on and engine running and after 0.5 seconds.
- Set Condition:
When the monitored AutoStick Up/Down Sense circuit voltage drops below 0.35 volts.
| Possible Causes |
| (T5) AUTOSTICK UP/DOWN SENSE CIRCUIT SHORT TO GROUND |
| (T5) AUTOSTICK UP/DOWN SENSE CIRCUIT SHORT TO ANOTHER CIRCUIT |
| SHIFT LEVER ASSEMBLY |
| TRANSMISSION CONTROL MODULE |
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Diagnostic Test
1. CHECK IF THE DTC IS CURRENTStart the engine in park.
With the scan tool, read the AutoStick® voltage.
Does the scan tool AutoStick voltage read below 0.35 volts?
Yes
- Go To 2
No
- Go To 5
2. CHECK THE SHIFT LEVER ASSEMBLY
Turn the ignition off to the lock position.
Disconnect the Shift Lever Assembly harness connector.
Start the engine in park.
With the scan tool, read the AutoStick voltage.
Does the scan tool AutoStick voltage read below 0.35 volts?
Yes
- Go To 3
No
- Replace the Shift Lever Assembly per the Service Information.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
3. CHECK THE (T5) AUTOSHIFT UP/DOWN SENSE CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off to the lock position.
Disconnect the PCM C3 harness connector and connect Miller tool #8815.
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller tool #8815 to perform diagnosis.
Measure the resistance between ground and the (T5) AutoStick Up/Down Sense circuit.
Is the resistance below 5.0 ohms
Yes
- Repair the (T5) AutoStick Up/Down Sense circuit for a short to ground.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No
- Go To 4
4. CHECK THE (T5) AUTOSHIFT UP/DOWN SENSE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
Measure the resistance between the (T5) AutoStick Up/Down Sense circuit and all other circuits in the Shift Lever Assembly harness connector.
Is the resistance below 5.0 ohms between the (T5) AutoStick Up/Down Sense circuit and any other circuit(s) in the Shift Lever Assembly harness connector.
Yes
- Repair the (T5) AutoStick Up/Down Sense circuit for a short to another circuit(s).
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No
- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the PCM per the Service Information. With the scan tool, perform QUICK LEARN.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
5. CHECK THE AUTOSTICK VOLTAGE WHILE SHIFTING
Start the engine in park.
With the brakes firmly applied, shift into AutoStick.
With the scan tool, monitor the AutoStick voltage while shifting both Up and Down.
Did the scan tool AutoStick voltage drop below 0.35 volts at any given time?
Yes
- Replace the Shift Lever Assembly per the Service Information.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No
- Go To 6
6. CHECK 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 wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No
- Test Complete.