P0803 code meaning
Upshift/Skip Shift Solenoid Control Circuit
Powertrain system Generic code P08xx codes Check engine light
What P0803 means
GM's skip-shift (CAGS) on manual gearboxes such as the T56 and TR6060 uses an engine-module solenoid in the shifter housing that, at light load and low speed blocks the way from 1st into 2nd and 3rd so the driver shifts 1 to 4 – a measure for fuel economy ratings; the 1-4 lamp (P0804) shows it. P0803 means the solenoid control circuit is open. GM's tables check the low-side driver while it is off: too low a voltage or over 200 kΩ to ground, with at least 9 V and over 250 rpm, 5 of 6 samples of 250 ms (2019 LT5: 20 of 25), type B with the MIL after two trips; shorts are P080C and P080D. An open circuit leaves the solenoid unpowered, so 1 to 2 always works. 'Skip-shift eliminators' with the wrong resistance are a frequent cause.
P0803 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P0803
- Check engine lamp after two trips
- 1-4 lockout no longer works (1-2 always possible)
- Otherwise no change in driving
Common causes of P0803
- Most likelySolenoid unplugged or replaced by a skip-shift eliminator with the wrong resistance
- Most likelyConnector at the gearbox loose or corroded
- PossibleSolenoid coil open
- PossibleHarness damaged
- Less likelyEngine module driver faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Skip shift solenoidSolenoid wiringEngine control module
What each part of P0803 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 8 | Area: transmission. |
| 03 | The exact fault in that area. |
What to do next
- Note P0803 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0803
What does P0803 mean?
P0803 means "Upshift/Skip Shift Solenoid Control Circuit". GM's skip-shift (CAGS) on manual gearboxes such as the T56 and TR6060 uses an engine-module solenoid in the shifter housing that, at light load and low speed blocks the way from 1st into 2nd and 3rd so the driver shifts 1 to 4 – a measure for fuel economy ratings; the 1-4 lamp (P0804) shows it. It is a generic code, so it means the same on every make.
Is it safe to drive with P0803?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0803 fail an emissions test?
Yes, it can. P0803 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0803 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0803 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.