P0641

P0641-SENSOR REFERENCE VOLTAGE 1 CIRCUIT





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

A common 5-volt power supply is used by both the primary and secondary pressure sensors as well as an internal ROM Assembly. If the power supply does not maintain a predetermined voltage range to the pressure sensors after the period of 5.0 seconds, the Transmission Control Module (TCM) sets the DTC and illuminates the MIL.

- When Monitored:
Ignition on with system voltage between 9.0 and 16.0 volts.

- Set Condition:
When the monitored input voltage from primary pressure sensor and secondary pressure sensor is less than 0.005 volts for a continuous period of 5.0 seconds.





Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview

1. CHECK TO SEE IF THE DTC IS ACTIVE
1. With the scan tool, read Transmission DTCs.

Is the status Active or is the Starts Since Set counter 2 or less for this DTC?

Yes

- Go To 2

No

- Go To 5

2. CHECK THE (T72) 5-VOLT SUPPLY CIRCUIT VOLTAGE




1. Turn the ignition off to the lock position.
2. Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
3. Ignition on, engine not running.
4. Measure the voltage of the (T72) 5-volt Supply circuit.

Is the voltage 5.0 volts (± 0.5 volts)?

Yes

- Replace the CV Transmission or the Valve Body.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- Go To 3

3. CHECK THE (T72) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN




1. Turn the ignition off to the lock position.
2. Disconnect the TCM C2 harness connector.
3. Measure the resistance of the (T72) 5-volt Supply circuit between the TCM C2 harness connector and the Transmission Solenoid/Pressure Switch Assembly harness connector.

Is the resistance above 5.0 ohms?

Yes

- Repair the (T72) 5-volt Supply circuit for an open.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- Go To 4

4. CHECK THE (T72) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (T72) 5-volt Supply circuit.

Is the resistance below 5.0 ohms?

Yes

- Repair the (T72) 5-volt Supply circuit for a short to ground.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- 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.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

5. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform CVT TRANSMISSION VERIFICATION TEST. CVT Transmission Verification Test

No

- Test Complete.