P0803: Upshift/Skip Shift Solenoid Control Circuit
What to do
No effect on the transmission and nothing to worry about mechanically — the forced 1-to-4 shift simply stops happening, which most drivers regard as an improvement. Mention if a skip shift eliminator has ever been fitted, as that is a common cause of this code.
What this code means
A circuit fault in the solenoid that forces a first-to-fourth gear change on some manual-transmission vehicles. The device exists purely to improve measured fuel economy: under light throttle at low speed it locks out second and third, obliging the driver to shift straight into fourth.
It is widely disliked and widely defeated, which is relevant to diagnosis. An aftermarket eliminator — essentially a resistor substituting for the solenoid — is a common fitment, and one fitted with the wrong value, or fitted badly, sets this code. So on a vehicle where the fault appeared without warning, it is worth asking whether anything was fitted in that circuit before assuming the solenoid failed.
The fault itself is harmless. With the solenoid inoperative the lockout simply stops happening, and the driver gets the second gear they wanted.
Likely causes
Start here
- Faulty skip shift solenoid · moderate
- Aftermarket skip shift eliminator fitted · easy
Less common
- Open circuit in solenoid wiring · moderate
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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- The car — make, model, year and engine. The same fault behaves differently on each.
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