P0783

Diagnostic Chart:

Wiring Diagram:

When a gear is commanded on, the vehicle speed to turbine shaft speed ratio is monitored to assure the correct gear ratio. 4th gear stuck on indicates that another gear was commanded but the actual ratio driving the vehicle is equal to 4th gear. This is a calculated value (turbine shaft speed/vehicle speed = gear ratio). 4th gear clutch is turned Off by grounding circuit 898 at the PCM.

DTC PARAMETERS

DTC P0783 is set when the PCM has detected the following conditions for more than three seconds, twice per ignition cycle.

^ 1st gear commanded by PCM.

^ Engine under load and load value is greater than 200.

^ Speed ratio across the torque converter, engine speed versus turbine shaft speed, less than 180. A speed ratio of 255 would be TCC On.

^ No noise on turbine shaft or vehicle speed signals.

^ Vehicle speed greater than 5 km/h (3 mph).

^ Turbine shaft speed greater than 224 rpm.

^ Turbine shaft speed to vehicle speed ratio equals 4th gear for more than 200 milliseconds.

TEST DESCRIPTION

Numbered steps below refer top numbered steps on chart.

1. Check for DTC's P0766, P0768 or P0769. They must be eliminated first as a possible cause of DTC P0783.

2. Check actuator operation. Use actuator quick check. The actuator quick test will PWM the actuators at a set rate. Listen and compare the noise of the 3rd gear actuator to that of the other actuators. The noise should be similar. Actuator Quick Chart

NOTE: To check actuator operation, command actuator quick test using the scan tool.

3. Problem could be a mechanical failure. This step begins internal diagnosis.

4. As air pressure is applied and released, the clutch plates should also apply and release. If the clutch plates are moving normally, the problem is probably in the valvebody. If clutches are not moving correctly, the problem is in the end cover or an internal transaxle problem exists.

REPAIR VERIFICATION

Monitor DTC menu "Code Status" for "Pass Since Code Clear" and "Pass This Ignition Cycle." When both have passed, repair is verified.

Criteria for pass:

^ Engine running.

^ Power present at actuators and no active faults exist for this actuator.

DIAGNOSTIC AIDS

When attempting to diagnose an intermittent problem use the Scan tool* to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem.

* Select MALF History and code status from DTC menu of Scan tool.

^ This code may set or intermittent 4th gear starts may be caused by a poor electrical connection at either the PCM, actuator connector plate or Under Hood Junction Block (UHJB) terminals. Wiggling connectors while performing an actuator quick test may help isolate the problem area.

Check the tightness of the female terminal grip with a spare male terminal.

^ This DTC will probably be accompanied by DTC P0741 - No TCC, DTC P0732 - No 2nd Gear, and DTC P0733 - No 3rd Gear.