P0641

P0641-SENSOR REFERENCE VOLTAGE 1 CIRCUIT





For a complete wiring diagram Refer to Diagrams/Electrical. Electrical Diagrams


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 0.05 volts for a continuous period of 5.0 seconds.







Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. CVT - Pre-Diagnostic Troubleshooting Procedure



Diagnostic Test


1. CHECK TO SEE IF THE DTC IS ACTIVE

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

No

- Go To 5



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





Turn the ignition off to the lock position.

Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.

Ignition on, engine not running.

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 VERIFICATION TEST. Verification Tests

No

- Go To 3



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





Turn the ignition off to the lock position.

Disconnect the TCM C2 harness connector.

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 VERIFICATION TEST. Verification Tests

No

- Go To 4



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





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 VERIFICATION TEST. Verification Tests

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 VERIFICATION TEST. Verification Tests



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 shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform CVT VERIFICATION TEST. Verification Tests

No

- Test Complete.