P0957
P0957 - AutoStick(R) Circuit Low
For a complete wiring diagram, refer to.
Theory of Operation
The AutoStick(R) switch contains two hall effect switches connected to ground. The PCM has two separate inputs, upshift and downshift. When the PCM detects an input from the switch, upshift or downshift, it will shift the transmission to the desired gear. If the PCM detects both inputs at the same time, the DTC will set.
• When Monitored: Whenever the engine is running.
• Set Condition: The transmission is not in the AutoStick(R) position and the upshift or downshift is reporting closed - less than 0.3 volts or if both switches are reported closed at the same time.
Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - Determine if the DTC is Current
• With the scan tool, check the STARTS SINCE SET counter for P0952.
• This counter only applies to the last DTC set.
Is the Starts Since Set counter set at 0?
Yes
• Go to Test Step 2.
No
• Go to Test Step 5.
Test Step 2 - Checking the AutoStick(R) Switch
• Turn the ignition OFF to the lock position.
• Disconnect the AutoStick(R) switch harness connector.
• Ignition ON, engine not running.
• Measure the voltage of both the AutoStick(R) upshift and downshift signal circuits.
Is the voltage more than 5.0 volts on both circuits?
Yes
• Replace the AutoStick(R) switch.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 3.
Test Step 3 - Check the AutoStick(R) Downshift Signal Circuit for a Short to Ground
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 Special Tool #8815 to perform diagnosis.
• Turn the ignition OFF to the lock position.
• Disconnect the C4 PCM harness connector.
• Measure the resistance between ground and the AutoStick(R) downshift signal circuit.
Is the resistance less than 100k ohms?
Yes
• Repair the AutoStick(R) downshift signal circuit for a short to ground.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 4.
Test Step 4 - Check the AutoStick(R) Upshift Switch Signal Circuit for a Short Ground
• Measure the resistance between ground and the AutoStick(R) upshift signal circuit.
Is the resistance less than 100k ohms?
Yes
• Repair the AutoStick(R) upshift signal circuit for a short to ground.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Using the schematics as a guide, check the powertrain control module terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check tune-ups or service bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM. Refer to With the scan tool, perform Quick Learn.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
Test Step 5 - 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 shorts and open circuits.
• With the scan tool, check the event data to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
• Repair as necessary.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Test Complete.