DTC 75

Diagnostic Chart:

Wiring Diagram:

3RD GEAR STUCK ON
When a gear is commanded on, the vehicle speed to turbine speed ratio is monitored to assure the correct gear ratio is achieved. Third gear stuck on indicates that another gear was commanded but the actual ratio driving the vehicle is equal to 3rd gear. This is a calculated value (turbine speed/vehicle speed = gear ratio). Third gear clutch is turned off by grounding circuit 583 at the PCM.

DTC OR INFORMATION FLAG PARAMETERS
DTC 75/information flag is set when flagged on when the PCM has detected the following conditions for more than three seconds twice per ignition cycle.
^ 1st gear commanded by PCM.
^ No noise on turbine or vehicle speed signals.
^ Vehicle speed greater than 5 km/h (3 mph).
^ Turbine speed greater than 224 rpm.
^ Speed ratio across the torque converter, engine speed versus turbine speed, less than 180. A speed ratio of 255 would be TCC on.
^ PCM calculated engine load value is greater than 200.
^ Turbine to vehicle speed ratio equals 3rd gear.

TEST DESCRIPTION
Numbered steps below refer to numbered steps on chart.
1. Check for information flags 73, 74, or 98. They must be eliminated first as a possible cause of DTC or information flag 75.
2. Check actuator operation. Use actuator quick check. The actuator quick test will Pulse Width Modulate (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.
3. Problem could be a mechanical failure. This step begins internal diagnosis.
4. Cross leaks to/from 3rd clutch oil passages can cause 3rd clutch to be on at all times. Possible leak due to seals, gaskets, porosity etc.
5. As air pressure is applied and released, the clutch plates should also apply and 1elease. 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.

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 from Scan tool Transmission Control Module (TCM) menu.

^ This DTC may set or intermittent 3rd gear starts may be caused by a poor electrical connection at either the PCM, actuator connector plate or Underhood 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 25 - No TCC and DTC 22 - No 2nd gear.