P0997 Code: Shift Solenoid F Control Circuit Range/Performance

What the P0997 code means

Solenoids are electric valves that direct hydraulic pressure to the clutches and brakes inside an automatic transmission. Shift solenoid F opens or closes the fluid path to one specific clutch, and the combination of solenoids that are on or off decides which gear you are in. The transmission computer commands them and watches both their electrical circuit and the result, which it judges from the input and output shaft speeds.

The P0997 code is set when the control circuit of the solenoid is outside its operating range. This is an electrical fault. The suspects are the wiring, the connector (very often the case pass-through connector, which can leak fluid), the solenoid itself, or the control module.

On any transmission code, check the fluid first. The level has to be right using the manufacturer procedure, which often calls for the engine running at a specific temperature. The fluid should be red or pink and should not smell burnt. Low or worn fluid causes slipping, harsh shifts and solenoid or gear ratio codes that go away once the fluid is corrected.

This kind of fault usually does not show up with a multimeter, because electrically everything looks fine. You have to compare what the part says with reality, using a pressure gauge, a thermometer, a tachometer, or by commanding the component with the scan tool and watching whether the physical result matches the command.

Read the P0700 guide to understand how transmission codes are retrieved and why you need a scan tool that can talk to the transmission module, not just the engine computer.

P0997 code symptoms

• Check engine light or transmission warning light on.
• Harsh shifts, late shifts or shifts that never happen.
• Limp mode: the transmission stays in one fixed gear, often 2nd, 3rd or 4th.
• Slipping or high rpm in certain gears.

Likely causes of the P0997 code

1. Transmission connector with fluid inside or corrosion. Very common at the case pass-through connector.
2. Damaged internal or external wiring, from heat or from rubbing.
3. Solenoid with an open or shorted coil. The resistance is out of specification.
4. Transmission control module. Uncommon, so rule out everything else first.

How to diagnose the P0997 code step by step

1. Check the fluid level and condition using the manufacturer procedure.
2. Read all the codes in the transmission module with a scan tool that can access it.
3. Measure the solenoid resistance at the transmission connector and compare it with the service manual.
4. Check the insulation to ground. It should read infinite.
5. Command the solenoid with the scan tool and listen for the click.
6. Inspect the case connector. Look for fluid inside it or green, corroded pins.

How to fix the P0997 code

• Repair the connector or the wiring.
• Replace the solenoid, or the whole valve body if the solenoid is built into it.
• Clear the adaptations and run the relearn procedure.
• Clear the codes and confirm the repair with a road test.

Technical reference data

• Shift solenoids (on/off type): roughly 10 to 30 ohms.
• Pressure or linear solenoids (PWM control): roughly 3 to 8 ohms.
• Normal transmission fluid temperature: 70 to 95 °C (158 to 203 °F).
• These values are only a guide, so look up the manufacturer data for your vehicle.

Brand-specific notes

After you replace solenoids or a valve body, it is usually necessary to clear the adaptations and run a relearn with a scan tool, whatever the brand.

P0997 on Aisin and Jatco

On many of these transmissions the solenoids sit in the valve body, and you reach them by removing the pan.

P0997 on GM and Ford

The same layout applies to the GM 6T and Ford 6R transmissions, where the solenoids are in the valve body behind the pan.

P0997 on Volkswagen

On the Volkswagen DSG, and on many modern transmissions, the solenoids are sold only together with the valve body or with the integrated control module, which is the mechatronic unit.

Frequently asked questions about P0997