What it means
General electrical fault on the upshift/skip-shift solenoid control circuit — used on manual-transmission performance vehicles to force a skip from 1st straight to 4th under low-load cruise (CAFE fuel-economy feature). With the input invalid the lockout cannot be applied.
At a glance
- Usually lights the check-engine light
How it works
On vehicles equipped with a manual-transmission skip-shift feature, the upshift solenoid controls a lockout that can prompt a shift from first directly to fourth under certain low-load conditions. P0803 sets when the module detects an electrical fault in the solenoid control circuit, so the lockout may not operate.
Common causes
Most likely first.
- Open circuit in solenoid control wiring
- Short to ground or power in control wiring
- Loose or corroded connector
- Upshift/skip-shift solenoid failure
- Control module circuit fault
Symptoms
- Skip-shift feature may not operate
- Check-engine light may be on
How to diagnose it
- Scan for related transmission codes and save freeze-frame data, including vehicle speed, engine load, and skip-shift command if available.
- Check whether the skip-shift feature is being commanded and whether its indicator or lockout behavior matches the command.
- Inspect the skip-shift solenoid connector and wiring for corrosion, loose terminals, chafing, or damage.
- Test the control circuit for opens and shorts, and check the solenoid itself against the manufacturer’s specification.
- If the wiring and solenoid pass, check the control-module connector and output circuit.
Common fixes
- Secure or clean the skip-shift solenoid connector.
- Repair damaged or open solenoid-control wiring.
- Replace a failed skip-shift solenoid.
- Repair a confirmed control-module circuit fault.
Can I keep driving?
The car can usually be driven if the transmission shifts normally, though the skip-shift feature may be unavailable. Avoid hard driving if shifting becomes abnormal, and have the circuit checked before relying on the feature.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.