Guide To P0999 OBD Error Code Solutions

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This trouble code is generic, which would mean that it can apply to all the vehicles which are equipped with the OBD-II or the vehicles which are made since 1996 up to the present. The specifications on the definition, the troubleshooting steps as well as repairs can always vary from one vehicle make to another.

This can happen because of a lot of reasons and the mechanic should diagnose the specific cause for this code.

When the driver selects “D” on an automatic transmission, the TCM shifts through specific gear ratios by activating or deactivating of a number of shift solenoids which, in turn, control brakes, clutches, and bands in the automatic transmission. The result, optimally, is smooth acceleration and shifting of gears. The TCM checks the operation of the solenoid valves, consisting of a resistance check and speed sensor verification. If one of these checks fails, such as encountering an open circuit on Shift Solenoid F (SSF), the TCM disables that control circuit and sets OBD code P0999 – Shift Solenoid F Control Circuit High in PCM memory.

What causes this problem with the Shift Solenoid "F" Control Circuit High?

• Malfunctioning ECM
• There can be inoperative automatic transmission fluid
• TCM might be flawed
• Imperfect shift timing solenoid
• Distorted Pin/connector
• Issue of less ATF fluid
• Faulty Shift Solenoid 'F' Shift
• Solenoid 'F' harness is open or shorted
• Shift Solenoid 'F' circuit poor electrical connection
• Obstruction in ATF passages 

1. Auto Transmission Shift Solenoid - Defective car shift solenoid can be a major reason why P0999 code depicts. So make sure to replace it online so that you don’t have to face any further issues.
2. Automatic Transmission Valve Body Kit - A lot of issues can arise due to defective Automatic Transmission Valve Body Kit. Did you just see P0999 code flashing? Now you know the reason why it is appearing. Get it inspected and replaced on time.
3. Powertrain Control Module - P0999 code flashing? Get your Powertrain Control Module inspected from a mechanic.
4. Automatic Transmission Filter - Everything is okay with the ECM and still OBD code P0999 triggering? Then there must be some defects in Automatic Transmission Filter. Replace them as soon as possible.
5. Engine Wiring Harness - It is an important auto part which needs full care. A faulty Engine Wiring Harness can be a reason behind the flashing up of P0999 code.
6. Body Control Module Component - OBD Code P0999 can appear because of faulty Body Control Module Component.
7. Automatic Transmission Fluid - P0999 error code also relates to problems with the Automatic Transmission Fluid. Find Automatic Transmission Fluid with us.

Willing to know some common symptoms of OBD Code P0999? Your wish is our demand. Have a look at them below:

Common Symptoms

• Stiff or rasping shifting
• Variable shifting
• Defective driveability
• Attached in gears
• Quirky acceleration
• Transmission gliding
• Incapable shift timing
• Declining performance

We have listed out some ways which would help you to correct the occurrence of OBD Code P0999. They are mentioned here as follows:

• Repair or replace faulty shift solenoid “F”
• Check and replace wrong transmission fluid
• Inspect and mend faulty shift solenoid circuit wiring
• It is essential to restore the quirks in the engine control module
• Rehabilitate the flawed in the shift solenoids wiring and connectors

There is no need to get strained if your OBD Code is still flashing up as we are here at your service. Have a look at our superior variety of Transmission Shift Solenoid, Shift Solenoid Valve, Transmission Control Module, Powertrain Control Module, Engine Control Module, Transmission Fluid and many more. Now all your problems would vanish within no time.

If you want to easily diagnose this P0999 fault code, then all you have to do is to follow the steps which are mentioned below:

A good starting point is always a technical service bulletin search for your particular vehicle. Carefully inspect the automatic transmission fluid. You must change you fluid if it is grimy, smells burnt, overfilled and unusual colour. If you've owned your vehicle for 30,000 to 60,000 miles and you do not remember when was the last time you changed you fluid or have any records of it, not only may this be your issue, but you should follow your maintenance schedule to avoid this situation.

Former fluid is mucky fluid, grimy fluid can cause blockages and blockages can be a big reason why this fault code is appearing so you must change your fluid! The manufacturers recommended steps should be followed properly when you are inspecting ATF. This basic step can differ a meaningful amount between the models as well as makes. The fluid is in nice condition, code is still present and symptoms exist? It all depends upon your specific model, the shift solenoid may be accessible externally.

Now if you find out that this is the case, then you should check the solenoid and its harness/connectors to find out the signs of defect. All the issues should be repaired or replaced as per the need. It would be helpful if you will have a peak for any leaks as well! If your shift solenoid is internal, then you should attempt to access it, work around it for now. Exhaust other avenues, internal transmission diagnosing and repairing should be left to a certified technician. The TCM and harness' involved in this circuit may be subject to rasping road conditions so make sure everything is complete in all aspects.

After that the shift timing solenoid should be inspected. You may be able to test the solenoid itself multiple ways. One test may include a resistance test where you use a multimeter to measure the resistance between the pins in the solenoid to verify to a degree its electrical integrity. Then the other would include manually applying voltage to the solenoid to verify its mechanical operation. You should specify either one in your manufacturers’ service manual/technical literature.

The circuit from the TCM should be tested properly. Then check the functionality of the sensor and its circuit by performing the same tests as above but from the pins at the TCM and/or ECM. This trick would be very helpful in verifying the integrity of the solenoid as well as electrical integrity.

Common Mistakes When Diagnosing The P0999 Code

Common mistake which is made when you are diagnosing the P0999 trouble code is that you do not inspect the shift solenoid circuitry when the shift solenoids are being replaced. The technicians should keep this thing in mind that they must look electrical components before replacing any parts which can give rise to P0999 error code.