P1661-SENSOR GROUND REFERENCE CIRCUIT

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

The Oil Temperature Sensor , Primary and Secondary Oil Pressure Sensor and the Input Speed Sensor use a common ground circuit that returns to the Transmission Control Module (TCM). If all of these circuits show an open (high voltage) the DTC will set.

When Monitored:
With the ignition on and a system voltage between 9.0 and 16.0 volts.
Set Condition:
When all are present for the period of 200 msec:

Transmission Fluid Temperature Sensor voltage is greater than 2.5 volts.
Primary Pressure Sensor voltage greater than 5.0 volts.
Secondary Pressure Sensor voltage is greater than 5.0 volts

Possible Causes

(T13) SENSOR GROUND CIRCUIT OPEN

INTERNAL TRANSMISSION

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 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

Go To 4

2. CHECK THE (T13) SENSOR GROUND CIRCUIT FOR AN OPEN

Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
Measure the resistance of the (T13) Sensor Ground 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 (T13) Sensor Ground circuit for an open.

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

Go To 3

3. CHECK THE (T13) SENSOR GROUND CIRCUIT FOR AN OPEN INTERNALLY

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 and program the TCM per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

Does the DTC reset during the Verification procedure?

Yes

Replace the CV Transmission or repair the valve body (internal wiring) per the Service Information.
Perform CVT VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - CVT - STANDARD PROCEDURE)

Test Complete.

4. 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.