Transmission not shifting correctly?

The is a fault in the transmission control system and a diagnostic scan might tell you what control fault is causing this. It could be the speed sensor or throttle position sensor. THis gudie can help as well

https://www.2carpros.com/articles/automatic-transmission-problems

Please run down this guide and report back.

One is the vehicle speed sensor and the other two are input and out shaft sensors. Any one of them can be the culprit but each sensor fault would be specific to their problem. Some trouble codes do not trigger the Check Engine Light and only going into diagnostic mode would you be able to now if anything is wrong.
Sometimes a fault with the throttle position sensor is not captured by the ECM and only looking at live data would you be able to understand if it is working correctly.

Sorry for the delay in getting back to you.

This is the rectification procedure from the shop manual. Go through it and see if there is anything you have missed out.

DTC P0720/9: COUNTERSHAFT SPEED SENSOR
Using scan tool, retrieve A/T freeze data. Clear fault codes and road test vehicle under same conditions freeze data was recorded. If fault code returns, go to next step. If fault code does not return, problem is intermittent, check mainshaft speed sensor and PCM connections.

Ensure countershaft speed sensor is installed properly. Disconnect countershaft speed sensor harness connector. Using a DVOM, measure resistance between sensor terminals.

If resistance is not 400-600 ohms, replace countershaft speed sensor. If resistance is 400-600 ohms, disconnect 16-pin PCM harness connector "D". Check for continuity between ground and 16-pin PCM harness connector "D", terminals No. 16 (Green wire) and No. 10 (Blue wire). See Figure.

If continuity is present, repair short to ground in Green wire or Blue wire between PCM and countershaft speed sensor. If continuity is not present, reconnect countershaft speed sensor harness connector. Measure resistance between 16-pin PCM harness connector "D", terminals No. 16 (Green wire) and No. 10 (Blue wire).

If resistance is 400-600 ohms, check for loose PCM harness connectors. Replace PCM with a known-good unit if necessary. If resistance is not 400-600 ohms, repair loose connection or open in Green wire or Blue wire between 16-pin PCM harness connector "D" and countershaft speed sensor harness connector.

Based on symptoms it is difficult diagnose the problem and since trouble codes are present, we need to have it diagnosed and rectified. If after the codes are cleared and do not come back and the symptoms are still present, we would need to test the hydraulic pressures etc.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.

Cheers, Ken

Welcome to 2CarPros.

The first thing that comes to mind is low fluid. Have you checked it? IF it is clean and full, my next suspect is the transmission clutch pressure control solenoid. Here are directions to test it. The attached pictures correlate with these directions.

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A/T CLUTCH PRESSURE CONTROL SOLENOID VALVES A AND B TEST
Test

picture 1

1. Disconnect the A/T clutch pressure control solenoid valves A and B 2P connectors.
2. Measure the resistance of the A/T clutch pressure control solenoid valves A and B between the No. 1 and No. 2 terminals of each connector.
STANDARD: About 5.0 ohms
3. If the resistance of either A/T clutch pressure control solenoid is out of standard, replace the A/T clutch pressure control solenoid valves A and B.
4. Connect the No. 1 terminal of the A/T clutch pressure control solenoid valve A (and B) to the battery positive terminal, and connect the No. 2 terminal to the battery negative terminal. A clicking sound should be heard.
5. If not, remove the A/T clutch pressure control solenoid valves A and B.
6. Check the fluid passage of the A/T clutch pressure control solenoid valves for dust and dirt.

picture 2

7. Connect the No. 1 terminal of the A/T clutch pressure control solenoid valves A and B to the battery positive terminal, and connect the No. 2 terminal to the battery negative terminal. Make sure the A/T clutch pressure control solenoid valves A (A) and B (B) move.
8. Disconnect one of the battery terminals and check valve movement.

NOTE: You can see the valve movement through the fluid passage in the mounting surface of the A/T clutch pressure control solenoid valves A and B body (C).

9. If either valve binds, or moves sluggishly, or if the A/T clutch pressure control solenoid does not operate, replace the A/T clutch pressure control solenoid valves A and B.

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Here are a few links you may find helpful when testing:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

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If you find that is the problem, here are the directions for replacement. Picture 3 correlates with these directions.

A/T CLUTCH PRESSURE CONTROL SOLENOID VALVES A AND B TEST
Replacement

picture 3

1. Remove the mounting bolts and the A/T clutch pressure control solenoid valves A and B (A).
2. Clean the mounting surface and fluid passage of the A/T clutch pressure control solenoid valves A and B and the transmission housing.
3. Install a new A/T clutch pressure control solenoid valves A and B with a new gasket (B), new O-rings (C), ATF feed pipes (D), and harness clamp bracket (E).

NOTE: Install the filter side of the ATF feed pipes in the transmission housing.

4. Check the A/T clutch pressure control solenoid valve connectors for rust, dirt, or oil, then connect them securely.

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Also, here are the directions for testing shift solenoids.

See picture 4 and 5

1. Disconnect the shift solenoid valve B or C 2P
2. Measure the resistance between the No. 1 and No. 2 terminals of the shift solenoid valve B or C.
STANDARD: 12 - 25 ohms
3. Replace the shift solenoid valve B or C if the resistance is out of standard.
4. If the resistance is within the standard, connect the No. 2 terminal of the shift solenoid valve B or C connector to the battery positive terminal, and connect the No. 1 terminal to the battery negative terminal. A clicking sound should be heard. Replace the shift solenoid valve B or C if no clicking sound is heard.

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Check these things and let me know what you find. Also, let me know if you have questions.

Take care,
Joe

Hi woodsplace,

Symptoms indicates the shift solenoids could be sticking and when this occurs, shifting is affected. They might not throw any codes and as the shift sensors are external, remove them and try cleaning to see if it works. THis gudie can help as well

https://www.2carpros.com/articles/automatic-transmission-problems

Please run down this guide and report back.

Hi oy,

Get a scan done to retrieve for trouble codes and let me know what you find.

Autozone and most major parts outlets provides free scanning services.

The D4 indicator light blinking indicates an error has been detected in the transmisison control system.

Without retrievng the trouble code, it is not possible to diagnose the problem.