P1790 Code - Fault Immediately After Shift
Quick Answer
The P1790 diagnostic trouble code (DTC) indicates a fault that occurs immediately after a shift in the vehicle's transmission. Common causes include Low transmission fluid level or dirty fluid, Faulty shift solenoids or sensors, Mechanical issues within the transmission. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1790 indicates Fault Immediately After Shift.
- Common causes
- Common causes include Low transmission fluid level or dirty fluid, Faulty shift solenoids or sensors, Mechanical issues within the transmission.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P1790 Description
The P1790 diagnostic trouble code (DTC) indicates a fault that occurs immediately after a shift in the vehicle's transmission. This fault can lead to noticeable performance issues and may affect the overall drivability of the vehicle. When this code is triggered, it means that the transmission control module (TCM) has detected a problem during the shifting process, which could result in harsh shifting, delayed engagement, or even the transmission slipping out of gear.
Common Causes of P1790
- Low transmission fluid level or dirty fluid
- Faulty shift solenoids or sensors
- Mechanical issues within the transmission
- Wiring or electrical connection problems
- Malfunctioning TCM or transmission control unit (TCU)
Symptoms of P1790
- Harsh shifting or jerking when changing gears
- Delayed engagement when shifting from park to drive or reverse
- Transmission slipping out of gear unexpectedly
- Loss of power or acceleration during gear changes
- Illumination of the Check Engine Light
How to Fix P1790
- Start by checking the transmission fluid level and condition. Top off or replace the fluid if necessary.
- Inspect the shift solenoids, sensors, and wiring for any signs of damage or corrosion. Replace any faulty components.
- Perform a thorough diagnostic scan to identify any specific fault codes related to the transmission.
- Test the TCM/TCU for proper functionality and reprogram or replace if needed.
- If mechanical issues are suspected, such as worn clutch plates or gears, a transmission rebuild or replacement may be necessary.
Cost to Fix P1790
The cost of repairing a P1790 fault can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the cost can range from $200 to $800 or more, including parts and labor. Keep in mind that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to obtain quotes from multiple sources to get an accurate estimate for your specific vehicle.
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Code P1790 Information for Specific Makes
- P1790 Acura — Throttle Position Sensor Circuit Malfunction
- P1790 Buick — Transmission Control Module Checksum
- P1790 Cadillac — Transmission Control Module Checksum
- P1790 Chevrolet — Transmission Control Module Checksum
- P1790 Chrysler — Fault Immediately After Shift
- P1790 Dodge — Fault Immediately After Shift
- P1790 GMC — Transmission Control Module Checksum
- P1790 Honda — Throttle Position Sensor Circuit Malfunction
- P1790 Isuzu — Lock-Up Clutch Not Engaging
- P1790 Jeep — Fault Immediately After Shift
- P1790 Lexus — ST Solenoid Valve Circuit Malfunction
- P1790 Mazda — Throttle Position Sensor Malfunction
- P1790 RAM — Fault Immediately After Shift
- P1790 Toyota — ST Solenoid Valve Circuit Malfunction
Frequently Asked Questions about P1790 Code
1. What are the common symptoms of OBDII code P1790 (Fault Immediately After Shift)?
- Common symptoms include harsh shifting, delayed shifting, transmission slipping, and the transmission going into limp mode.
2. What are the possible causes of OBDII code P1790 (Fault Immediately After Shift)?
- Possible causes include low transmission fluid, a faulty transmission solenoid, a malfunctioning transmission valve body, or wiring issues.
3. How can I diagnose OBDII code P1790 (Fault Immediately After Shift)?
- Diagnosis typically involves using a scan tool to retrieve the code, checking the transmission fluid level and condition, inspecting the wiring and connectors, and testing the transmission solenoids.
4. Can driving with OBDII code P1790 (Fault Immediately After Shift) cause further damage?
- Continuing to drive with this code may lead to further damage to the transmission components, resulting in more costly repairs.
5. What are some repair tips for fixing OBDII code P1790 (Fault Immediately After Shift)?
- Repair tips may include checking and topping up the transmission fluid, replacing the transmission solenoid, inspecting and repairing any damaged wiring, and performing a transmission fluid flush.
6. Is it safe to continue driving my vehicle with OBDII code P1790 (Fault Immediately After Shift)?
- It is not recommended to drive the vehicle with this code present, as it can lead to transmission issues and potential safety hazards on the road.
7. How much does it typically cost to repair OBDII code P1790 (Fault Immediately After Shift)?
- The cost of repairs for this code can vary depending on the specific cause of the issue, but it may range from a few hundred dollars to over a thousand dollars.
8. Can OBDII code P1790 (Fault Immediately After Shift) be a DIY fix?
- Some basic repairs for this code, such as checking and filling the transmission fluid, can be done as a DIY fix. However, more complex issues may require professional help.
9. How urgent is it to address OBDII code P1790 (Fault Immediately After Shift)?
- It is important to address this code promptly to prevent further damage to the transmission and ensure the vehicle's safe operation.
10. What should I do if OBDII code P1790 (Fault Immediately After Shift) keeps coming back after repairs?
- If the code keeps reappearing after repairs, it may indicate an underlying issue that was not properly addressed initially. It is recommended to have a professional mechanic further diagnose the problem.
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