Normal/Performance Switch Circuit
The P0790 code means the vehicle's onboard diagnostic system has detected: Normal/Performance Switch Circuit. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $1,200 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
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What Are the Symptoms of P0790?
- Check Engine Light on
- Transmission mode switch malfunction
- Shift quality degradation
- Transmission may enter limp mode
What Causes P0790? (Most Likely First)
- Faulty transmission mode switch Very High
- Contaminated or degraded transmission fluid High
- Wiring or connector fault in the circuit Moderate
- TCM internal circuit failure Low
Can I Still Drive with P0790?
Short distances only. P0790 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does P0790 indicate?
P0790 indicates a problem with the normal/performance switch circuit. This affects the transmission control module's ability to properly manage shift timing and quality.
Should I continue driving with this code?
You can drive short distances at reduced speeds, but the transmission may shift harshly or enter limp mode. Continued driving with transmission codes can lead to additional damage and more expensive repairs.
Is this an internal transmission problem?
Not necessarily. Many transmission codes are caused by external issues like wiring faults, sensor failures, or fluid condition. Proper diagnosis can often identify issues that can be repaired without opening the transmission.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0790?
-
Use a scan tool to monitor Normal/Performance Switch data
-
Check transmission fluid level and condition
-
Inspect the transmission wiring harness and connector for damage or corrosion
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Compare sensor readings to manufacturer specifications at various operating conditions
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0790?
- 2010-2020 Ford F-150
- 2012-2019 Chevrolet Silverado
- 2011-2020 Toyota Camry
- 2009-2019 Honda Accord
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