P0847-SECONDARY OIL PRESSURE SENSOR CIRCUIT LOW

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

The Transmission Control Module (TCM) monitors the input voltage from the secondary pulley pressure sensor. When the voltage is below a predetermined limit a DTC will set.

When Monitored:
Ignition on, system voltage between 9.0 and 16.0 volts.
Transmission temperature greater than -20° C (-4° F)
No active DTCs from the following:
Primary Oil Pressure Sensor High
Sensor ground
Set Condition:
When the monitored voltage drops below 0.09 volts for the period of 5 seconds.

Possible Causes

(T72) 5 VOLT SUPPLY CIRCUIT OPEN

(T50) SECONDARY PRESSURE SENSOR SIGNAL CIRCUIT OPEN

(T50) SECONDARY PRESSURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND

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 THE SECONDARY PRESSURE SENSOR VOLTAGE

With the scan tool, read the Secondary Pulley Pressure Sensor voltage.

Is the voltage below 0.09 volts?

Yes

Go To 2

Go To 7

2. CHECK THE (T72) 5 VOLT SUPPLY CIRCUIT

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 in the Transmission Solenoid/Pressure Switch Assembly harness connector.

Is the voltage 5.0 volts (± 0.2 volts)?

Yes

Go To 3

Go To 6

3. CHECK THE (T50) SECONDARY PRESSURE SENSOR SIGNAL CIRCUIT

Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid/Pressure Switch Assembly harness connector.
Ignition on, engine not running.
Connect a jumper wire between the (T50) Secondary Pressure Sensor Signal circuit and the (T72) 5 Volt Supply circuit in the Transmission Solenoid/Pressure Switch Assembly harness connector.
With the scan tool, read the Secondary Pulley Pressure Sensor voltage.

Is the voltage 5.0 volts (± 0.2 volts)?

Yes

Replace CV Transmission or replace the Secondary Pressure Sensor (Valve Body) per the Service Information.

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

Go To 4

4. CHECK THE (T50) SECONDARY PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN

Turn the ignition off to the lock position.
Disconnect the TCM C2 harness connector.
Measure the resistance of the (T50) Secondary Pressure Sensor Signal 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 (T50) Secondary Pressure Sensor Signal circuit for an open or high resistance.

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

Go To 5

5. CHECK THE (T50) SECONDARY PRESSURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between ground and the (T50) Secondary Pressure Sensor Signal circuit.

Is the resistance below 5.0 ohms?

Yes

Repair the (T50) Secondary Pressure Sensor Signal circuit for a short to ground.

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

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

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

While back probing, measure the voltage of the (T72) 5 Volt Supply circuit in Transmission Solenoid/Pressure Switch Assembly harness connector.

Is the voltage 5.0 volts (± 0.2 volts)?

Yes

Repair the (T72) 5 Volt Supply circuit for an open or high resistance.

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

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

7. 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.