Guide To P0798 OBD Error Code Solutions

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In your vehicle the computer controls the automatic transmissions which actuate the gear shifts as well as the torque converter lockup. This is done using the electronic pressure control solenoids, when the readings of these solenoids aren’t in congruence with the parameters of the manufacturer the P0798 code will be set.

The pressure control solenoid is used by the auto transmission Control Module or the TCM to control the hydraulic pressure in the transmission. This pressure is required, so that the many clutch packs in the transmission can be applied, the purpose of these is to provide variant gear ratios as needed by the driver. These varied ratios ensure that the vehicle is efficiently propelled on the road, but when the TCM module starts to detect an issue with the pressure control solenoid, in terms of performance as per need, it will set P0798 code and the check engine light may also get illuminated.

What causes this problem with the Pressure Control Solenoid C Electrical?

• Low level of the automatic transmission fluid
• Transmission fluid is dirty or contaminated
• Internal mechanical failures noticed
• Blockage of Internal hydraulic passages
• Failure of the electronic pressure control solenoid
• Malfunction of the PCM or transmission control module

1. Transmission Fluid - You will have to check and replace the fluid as per need. At times you may just need to increase its level by refilling it. We have the best you can find, buy today from any of our warehouses across Toronto so that your car doesn’t suffer due to P0798 and other transmission errors.
2. Transmission Pressure Control Solenoid - All issues will have to be repaired and rechecked if fixed. If not, you will have to replace the entire solenoid. Follow this and solve the P0798 code.
3. Transmission Control Module - You can fix the issues via repairs, but if that’s not resolving the problem, opt for replacement. Parts Avatar has a wide range of aftermarket car parts for you. Simply find the one compatible with your vehicle on our website and place the order from the comfort of your home.
4. Automatic Transmission Solenoid - Try to repair or replace with Parts Avatar. We offer free shipping on orders over CAD $99. It’s simple to order, and you can track your shipment till it reaches your doorstep within a matter of days.

It is vital to know the symptoms of an issue as only then you would be able to solve the problem. So that’s why we have listed out some major symptoms of OBD Code P0798 here:

Common Symptom

• Vehicle goes into limp mode
• Harshness in shifting gears
• Transmission seems to be slipping
• Overheating of the transmission
• Reduction of fuel economy
• Failed torque converter clutches unable to lock up or disengage
• Shifting becomes disabled, becoming stuck in one gear
• No symptoms detectable
• Code is stored and the check engine light is illuminated

Want to correct the Trouble Code P0798? Read these points mentioned below:

• Flush/change the transmission fluid
• Rebuilding of transmission
• Repair/replace internal wiring harness in transmission
• Repair/replace solenoids or high-pressure pump

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

• Start your diagnosis with a thorough inspection of the transmission fluid on the dipstick. You’re mainly looking to check the level of the fluid present, the quality of it and if there are any odd smells coming from the fluid like that if burnt or contaminations. If you note that there’s a burnt smell, it is because the transmission was running on low level of transmission fluid and hence underwent some damages due to overheating. There may also be some internal mechanical failure.
• If indeed the fluid is burned then drop the transmission pan and check for any unusual material present, like clutch material, metal shavings or debris. You will have to clear the debris present in the pan and do a complete rebuild/fluid flush to sort this issue. A new torque converter will also mostly have to be installed for the transmission to function smoothly.
• If you found no contaminants and debris, then look for sorted or burned wiring/connectors within the internal transmission wiring system. Proceed to repairing or replacing this as per the requirement, you may also have to opt for full replacement of the internal transmission harness.
• Upon investigation if you found that all the internal wiring, connectors and components seem to be in good condition, then it’s time to connect your vehicle scanner to the diagnostic port and retrieve all the stored codes. Remember to freeze frame the data. Now clear the codes and go for test drive, wait until the code returns.
• If the PCM enter readiness mode and there’s no code returning, it’s a sign that you have an intermittent condition. In order to sort this issue, the problem may have to worsen so that the accurate diagnosis can be made.
• If the OBD error code has been reset, and the transmission is showing signs of slipping or delay in engagement you will have to check pump pressure. For this you will require a manual pressure gauge.
• Now locate the correct port using your vehicle manual and thread the end of the gauge to the port, and record the pressure of the pump. Now compare the readings you have found with that of the manufacturers and see if they are tallying. Accordingly proceed with repairs.
• Low pump pressure could be due to a failed pump, or clogged internal hydraulic passaged, failure of shift solenoids or electronic pressure regulator. In case you have to replace the entire pump, you will have to remove the whole transmission and also do a partial tear down.
• If your transmission seems fine but the code still returned, you will have to look for reference voltage and ground signals at the pressure control solenoid “C”. To do this, first disconnect all the related control modules from the circuit before checking resistance. This is done to ensure no further damage is caused.
• When the transmission level i slow check if there’s a leak by adding fluid. Clear the bottom of the pan and crossmember using a brake cleaner, and then spray foot powder on the whole area. This will make it easy to track down the path as well as the source of the leak.
• When you refill the transmission fluid and the code doesn’t return upon checking, then its a clear sign that the issue was caused due to low level of the transmission fluid.

Common Mistakes When Diagnosing the P0798 Code

• Overlooking pressure control solenoid or wiring problems
• Wrongly replacing the high-pressure pump