Transmission codes PO700 and PO777

Good morning,

This is a code for the pressure in the transmission.

You will need an advanced scan tool to monitor the action of the solenoids in the transmission. You cannot check them with a voltmeter as they are controlled with pulse width modulation from the control module.

In most cases, this is a wiring harness issue.

Roy

Theory of Operation

The Transmission Control Module (TCM) monitors the secondary line pressure (secondary pulley pressure) from the secondary pressure sensor. The TCM compares the actual secondary line pressure to the target (desired) line pressure. Failure to match the target line pressure over a given time will set the DTC.

- When Monitored:
Ignition on, engine running with the transmission not in neutral or park.

Transmission fluid temperature greater than -20° C (-4° F).

Brake Switch in the OFF mode.

Change rate of vehicle speed greater than 24 Km/h (15 mph).

Change rate of accelerator pedal position less than ± 6.25%.

Engine rpm greater than 450 rpm with a transmission fluid temperature greater than 20° C (68° F)

No active DTCs from the following:

- Line Pressure Solenoid
- Primary or Secondary Pressure Sensor
- Step Motor
- Secondary Solenoid electrical
- Input and Output Speed Sensor
- CAN Bus
- Set Condition:
When the secondary pressure goes down gradually below a predetermined value during a drive cycle. The DTC could be due to the failure of the secondary pressure control system, secondary pressure solenoid performance or line pressure solenoid. There are two possible setting conditions to set this DTC.

Condition one:

- Target secondary pressure minus the measured secondary pressure is greater than 0.25 MPa (36 psi) for two consecutive instances of a problem identification for the period of 1.5 seconds within a 30 second interval.

Condition two:

- Target secondary pressure minus the measured secondary pressure is greater than 2.0 MPa (291 psi) for the period of 800 msec.

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Always perform the CVT Pre-Diagnostic Troubleshooting procedure before proceeding. See: Continuously Variable Transmission/Transaxle, CVT > Initial Inspection and Diagnostic Overview > CVT - Pre-Diagnostic Troubleshooting Procedure

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