Low, degraded or contaminated transmission fluid affecting solenoid operation; Shift solenoid F sticking or worn internally; Damaged, chafed or corroded wiring or connector between the solenoid and the transmission control module; Blocked fluid passages or debris in the valve body; Internal transmission wear causing pressure loss that mimics a solenoid fault; Fault in the transmission control module or an outdated calibration known for this code on certain models.

P0997

Shift Solenoid F Control Circuit Range/Performance.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
9: AreaTransmission
97: FaultThe specific fault in that area

What it means

P0997 means the transmission control module has detected that the Shift Solenoid F control circuit is not performing as expected. The module commanded the solenoid and the electrical response or resulting gear or pressure behaviour did not match what it expected. The exact role of solenoid F varies by transmission, so the affected gears depend on the model and gearbox.

Symptoms

Gearbox warning light or malfunction indicator lamp on
Harsh, delayed or flared gear changes
Transmission stuck in one gear or in limp mode
Failure to select certain gears, especially under load
Poor fuel economy or unusual engine revs between shifts

Possible causes

Low, degraded or contaminated transmission fluid affecting solenoid operationlikely
Shift solenoid F sticking or worn internallylikely
Damaged, chafed or corroded wiring or connector between the solenoid and the transmission control modulelikely
Blocked fluid passages or debris in the valve bodypossible
Internal transmission wear causing pressure loss that mimics a solenoid faultpossible
Fault in the transmission control module or an outdated calibration known for this code on certain modelsrare

How to diagnose

Read all stored codes and freeze frame data to see gear, speed, temperature and load when the fault set, and note any related solenoid or ratio codes
Check transmission fluid level and condition against the manufacturer's procedure, looking for burnt smell, dark colour or metal particles
Inspect the transmission wiring harness and connector for chafing, fluid ingress, bent pins and corrosion
Check battery condition and charging voltage, as low supply voltage can cause circuit performance faults
Measure solenoid F resistance and compare it with the manufacturer's specification, and check the circuit for shorts or high resistance
Command the solenoid with a bi-directional scan function if available and watch for the expected response and gear change
Check for technical service bulletins or calibration updates relevant to the model and gearbox
Inspect the valve body and fluid filter for debris if electrical checks pass, following the model-specific procedure

How to fix

Correct the fluid level or replace the fluid and filter with the specified type if degraded
Repair or replace damaged wiring and connectors, cleaning any corrosion
Replace shift solenoid F, or the solenoid pack, if resistance or operation is out of specification
Clean or overhaul the valve body and clear debris if contamination or sticking is found
Repair internal transmission wear where pressure testing confirms it
Update the transmission control module calibration or replace the module only when a known fault or outdated calibration is confirmed

Can I keep driving?

Medium severity

The car can usually be driven short distances, but expect poor shifting or limp mode, and continued use risks further transmission damage. Have it diagnosed soon and avoid heavy loads or towing.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.