Drive with caution — fix soon.
This code means the transmission computer detected that the actual gear ratio in first gear doesn't match what it expects, usually because the gears aren't fully engaging or the clutches are slipping. It often points to low or worn transmission fluid, a faulty shift solenoid, or wear inside the transmission. Many cases are fixed with a fluid service or solenoid replacement, though severe internal wear can require a rebuild.
$150 – $3500
Varies by vehicle and root cause.
For short, gentle trips usually yes, but you shouldn't rely on it. A slipping first gear can overheat the transmission and cause much costlier damage, so get it diagnosed soon and avoid heavy acceleration or towing in the meantime.
It depends on the cause. A fluid service or single solenoid replacement might run $150 to $600, while internal clutch or transmission rebuild work can reach $1,500 to $3,500 or more.
It's moderately serious. It won't usually leave you stranded immediately, but it signals the transmission is slipping in first gear, which can progress to major damage if ignored.
Yes. Low, dirty, or burnt fluid is one of the most common and cheapest causes. A technician will often check and service the fluid first before assuming internal damage.