P1955 on Chevrolet: How to Diagnose & Fix
Transmission Fluid Pressure Relief Valve Performance
1 Chevrolet model · 1 documented issue · $350-$900 repair
P1955 on Chevrolet by model: symptoms, diagnosis and fix
On the E-Ray only, the 8-speed dual-clutch transmission carries an auxiliary fluid pump so the gearbox stays pressurized while the car is moving on electric power alone in Stealth or Shuttle mode. GM published Bulletin #25-NA-278 for 2024-2026 Corvette E-Ray models that display a Service Transmission message in the Driver Information Center along with an illuminated Check Engine MIL, with DTC P1955 (Transmission Fluid Pressure Relief Valve Performance) and/or P0867 (Transmission Fluid Pressure Performance) stored in the TCM. GM identifies the cause as auxiliary pump cavitation traced to the transmission pan fluid filter. This condition is specific to the hybrid E-Ray driveline and does not apply to the Stingray, Z06 or ZR1, which have no electric-only drive mode and no auxiliary pump duty cycle of this kind.
Common Symptoms
- Service Transmission message in the Driver Information Center
- Check Engine light (MIL) illuminated
- DTC P1955 and/or P0867 stored in the transmission control module
- Condition often noticed after driving in Stealth or Shuttle mode
How to Fix
Scan the TCM for P1955 and P0867 as current or history codes. Per Bulletin #25-NA-278, replace the transmission fluid pan filter and re-evaluate the vehicle - GM explicitly directs that no other repairs be attempted for these DTCs. The 15 transmission pan bolts are single-use fasteners and must be replaced and torqued in sequence with a GM-45059-A angle meter per the service information. Most affected cars are still inside the powertrain warranty, so have the work done at a Chevrolet dealer under the bulletin.
Sources for this issue (3)
P1955 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1955 mean on a Chevrolet?
P1955 stands for "Transmission Fluid Pressure Relief Valve Performance." Set in the Transmission Control Module when the commanded state of the transmission fluid pressure relief valve does not produce the expected hydraulic pressure response. On the C8 Corvette E-Ray's dual-clutch transmission, GM attributes this to auxiliary pump cavitation caused by a restricted transmission pan fluid filter: the starved pump cannot maintain pressure, so the TCM sees the relief valve circuit as underperforming. It typically sets alongside P0867 (Transmission Fluid Pressure Performance). GM explicitly directs technicians to replace the transmission pan fluid filter and to attempt no other repair for these codes. On Chevrolet it is documented across 1 model: Corvette.
What are the most common causes of P1955?
The most common causes of P1955 are: Restricted or clogged transmission pan fluid filter causing auxiliary pump cavitation (GM's stated cause on 2024-2026 Corvette E-Ray), Low transmission fluid level or aerated fluid, Auxiliary/electric transmission fluid pump performance degradation, Pressure relief valve or valve body solenoid sticking, Debris circulating in the transmission hydraulic circuit. The specific cause varies by vehicle.
How much does it cost to fix P1955 on a Chevrolet?
Published repair estimates on Chevrolet range from $350 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P1955 on a different make?
View P1955 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.