P0985 Shift Solenoid "E" Control Circuit Low

The P0985 trouble code is an OBD-II diagnostic trouble code related to the electronic control system of an automatic transmission.

P0985 – Shift Solenoid “E” Control Circuit Low

This code means that the transmission control module (TCM) or powertrain control module (PCM) has detected an electrical signal in the Shift Solenoid “E” control circuit that is lower than the expected value.

In simple terms, the transmission computer is commanding or monitoring Shift Solenoid “E,” but the electrical response from the circuit is too low or otherwise below the expected operating condition.

P0985 is primarily an electrical circuit fault code. It does not automatically mean that the transmission has low hydraulic pressure or that the transmission itself needs to be replaced.

What Does P0985 Mean?

P0985 – Shift Solenoid “E” Control Circuit Low

Automatic transmissions use electrically controlled solenoids to regulate hydraulic fluid.

The TCM sends electrical commands to these solenoids to control:

• Gear changes

• Hydraulic pressure

• Clutch engagement

• Shift valves

• Transmission operating modes

Shift Solenoid “E” controls one of the hydraulic circuits used by the transmission.

When the TCM detects that the electrical signal in the solenoid's control circuit is lower than the expected value, it can store P0985.

The exact function of Shift Solenoid “E” depends on the specific transmission.

What Is a Shift Solenoid?

A shift solenoid is an electrically operated valve inside or associated with an automatic transmission.

Its basic function is to control the movement of transmission fluid through hydraulic passages.

The process can be simplified as:

TCM command → Electrical solenoid activation → Hydraulic fluid movement → Clutch/valve operation → Gear change

If the solenoid cannot be controlled correctly, the transmission may not be able to engage the intended gear or hydraulic circuit.

What Does the “E” Mean?

The “E” identifies a specific shift-solenoid circuit according to the manufacturer's transmission design.

It does not universally mean that the transmission has five solenoids or that this is always the fifth solenoid physically installed.

Different transmissions use different solenoid layouts and naming conventions.

Therefore, the exact location of Shift Solenoid “E” must be confirmed using the vehicle-specific transmission service information.

What Does “Circuit Low” Mean?

The “Low” portion of P0985 refers to the electrical condition of the solenoid control circuit.

The TCM has detected that the circuit's electrical signal is below the expected range.

Possible causes include:

• Short to ground

• Faulty solenoid

• Damaged wiring

• Poor connector connection

• Open circuit

• Incorrect resistance

• Power supply problem

• Control-module problem

The exact electrical behavior depends on the design of the transmission's solenoid circuit.

Does P0985 Mean the Solenoid Is Bad?

No.

A defective Shift Solenoid “E” is one possible cause, but the code does not prove that the solenoid itself has failed.

For example, a control wire shorted to ground can pull the circuit voltage down and produce P0985.

A damaged connector or poor electrical connection can produce similar symptoms.

Therefore, the complete circuit should be tested before replacing the solenoid.

Symptoms of P0985

The symptoms depend on which transmission function is controlled by Shift Solenoid “E.”

Possible symptoms include:

• Check Engine Light

• Transmission warning light

• Harsh shifting

• Delayed gear changes

• Erratic shifting

• Transmission slipping

• Transmission stuck in one gear

• Missing a particular gear

• Unexpected downshifts

• Unexpected upshifts

• Delayed engagement of Drive

• Delayed engagement of Reverse

• Poor acceleration

• Higher engine RPM

• Reduced fuel economy

• Limp mode

Some vehicles may continue to drive almost normally.

In these cases, the Check Engine Light may be the only noticeable symptom.

Common Causes of P0985

Several electrical and transmission-related problems can trigger P0985.

Faulty Shift Solenoid “E”

The solenoid may have an internal electrical failure.

Possible problems include:

• Internal short

• Open winding

• Incorrect resistance

• Coil failure

• Internal mechanical sticking

If the solenoid does not have the correct electrical characteristics, the TCM may detect a low circuit condition.

Short to ground

A short between the solenoid control wire and ground can pull the electrical signal down.

This is one of the most important possibilities with a circuit-low code.

If the control wire is contacting ground, replacing the solenoid will not fix the underlying problem.

Open or damaged wiring

A damaged wire can prevent proper current flow through the solenoid circuit.

The harness may be affected by:

• Heat

• Vibration

• Chafing

• Pinching

• Corrosion

• Previous repairs

Depending on the circuit design, an open circuit can also cause the TCM to identify an abnormal low or missing control condition.

Connector problems

A loose or corroded connector can interfere with solenoid operation.

Possible problems include:

• Bent pins

• Loose terminals

• Corrosion

• Water intrusion

• Transmission fluid contamination

• Broken connector locks

Power supply problem

Some solenoid circuits depend on a common power supply.

If that supply is missing or significantly reduced, the solenoid may not operate correctly.

If multiple solenoid codes appear at the same time, a shared power supply or wiring problem should be considered.

Incorrect solenoid resistance

The solenoid coil should have a resistance within the manufacturer's specified range.

A resistance that is too low or too high can indicate an internal solenoid problem.

The correct resistance value varies by transmission.

Valve body problems

A solenoid can be electrically functional while its hydraulic circuit has a mechanical problem.

Possible causes include:

• Sticking valves

• Contamination

• Restricted passages

• Valve-body wear

These problems can cause shifting issues even when the solenoid electrical circuit is functioning correctly.

TCM fault

A control-module fault is possible, but it should generally be considered after the solenoid and wiring have been properly tested.

Can Low Transmission Fluid Cause P0985?

Low transmission fluid can cause:

• Poor shifting

• Hydraulic pressure problems

• Delayed engagement

• Transmission slipping

However, low transmission fluid does not normally cause an electrical circuit-low fault by itself.

The fluid level should still be checked during a complete transmission diagnosis, but the electrical circuit should not be ignored.

Can Dirty Transmission Fluid Cause P0985?

Contaminated fluid can contribute to:

• Sticking solenoids

• Valve-body problems

• Restricted hydraulic passages

• Erratic shifting

However, dirty fluid alone does not necessarily explain an electrical circuit-low code.

If P0985 is present, the solenoid's electrical circuit should be tested.

How Serious Is P0985?

The seriousness depends on the underlying cause.

A damaged connector or wire may be relatively simple to repair.

However, if the solenoid controls an important hydraulic circuit, incorrect operation can cause significant transmission problems.

Continued operation may contribute to:

• Harsh shifts

• Clutch slipping

• Excessive heat

• Accelerated internal wear

• Limp mode

Therefore, P0985 should be diagnosed rather than ignored.

Can You Drive With P0985?

If the transmission is still shifting normally, a short drive to a repair facility may be possible.

However, prolonged driving is not recommended.

Driving should be minimized if the vehicle has:

• Severe slipping

• Violent gear changes

• Loss of Drive

• Loss of Reverse

• Transmission overheating

• Limp mode

• Burning transmission fluid smell

These symptoms may indicate that the transmission is not controlling its hydraulic circuits correctly.

How to Diagnose P0985

A proper diagnosis should begin with the electrical circuit.

1. Scan the TCM

Use a professional diagnostic scanner and retrieve all stored and pending transmission codes.

Look for additional faults involving:

• Other shift solenoids

• Pressure-control solenoids

• Transmission temperature

• Gear ratios

• Transmission communication

• Power supply

If several solenoid codes appear simultaneously, look for a common electrical cause.

2. Check freeze-frame data

Review the operating conditions when P0985 was stored.

Important information may include:

• Engine RPM

• Vehicle speed

• Transmission temperature

• Selected gear

• Throttle position

• Solenoid command

• Transmission operating mode

This can help identify when the fault occurs.

3. Identify Shift Solenoid “E”

Use the correct transmission wiring diagram to identify:

• Solenoid location

• Connector

• Power supply

• Control wire

• Ground/control strategy

• TCM connection

Do not assume that “E” has the same location or function across different transmissions.

4. Inspect the wiring

Look for:

• Chafed insulation

• Broken wires

• Pinched wiring

• Melted sections

• Corrosion

• Previous repairs

• Loose harness clips

Pay particular attention to areas near the transmission and exhaust components.

5. Inspect the connectors

Check for:

• Bent pins

• Loose terminals

• Corrosion

• Water intrusion

• Transmission fluid contamination

• Damaged connector locks

A connector may appear properly connected while still having poor electrical contact.

6. Measure solenoid resistance

With the appropriate connector disconnected, measure the resistance of Shift Solenoid “E” according to the manufacturer's specifications.

If resistance is outside the specified range, the solenoid may be defective.

Do not rely on a universal resistance number because solenoid specifications differ between transmissions.

7. Check the circuit for a short to ground

Because P0985 indicates a circuit-low condition, the control circuit should be checked for an unintended connection to ground.

A short to ground can pull the circuit voltage down and cause the code.

8. Check power supply and control voltage

Verify that the solenoid receives the correct electrical supply and that the TCM can control the circuit correctly.

Depending on the transmission design, the TCM may control the solenoid through different switching strategies.

The manufacturer's wiring diagram should be followed.

9. Use a bidirectional scan tool

If supported, command Shift Solenoid “E” on and off with a professional scan tool.

This can help determine whether:

• The TCM can command the solenoid

• The electrical circuit responds

• The solenoid operates

• The transmission responds hydraulically

This can be particularly useful when the fault is intermittent.

10. Check hydraulic operation

If the electrical circuit and solenoid pass testing but transmission operation remains abnormal, the hydraulic system should be investigated.

Possible causes include:

• Sticking valves

• Valve-body wear

• Restricted passages

• Internal leakage

• Incorrect hydraulic pressure

Why a Circuit-Low Code Does Not Automatically Mean Low Transmission Pressure

This distinction is extremely important.

P0985 describes an electrical circuit condition.

It does not directly state that hydraulic pressure inside the transmission is low.

For example, a control wire shorted to ground can cause P0985 while the transmission's hydraulic pressure is completely normal.

Therefore:

Electrical circuit low ≠ hydraulic pressure low

The electrical system should be tested first.

P0985 After Transmission Repair

If P0985 appeared immediately after transmission repair or replacement, inspect everything that was disturbed during the repair.

Possible causes include:

• Connector not fully seated

• Bent connector terminal

• Pinched wiring

• Damaged harness

• Incorrect harness routing

• Solenoid connector contamination

• Loose electrical connection

If the problem appeared immediately after the repair, the repair area should be inspected carefully before assuming that an unrelated component has failed.

P0985 After a Transmission Fluid Change

A transmission fluid change normally does not directly cause an electrical circuit-low fault.

However, after transmission service, check:

• Correct transmission fluid

• Correct fluid level

• Correct filling procedure

• Electrical connector condition

• Harness condition

If fluid entered an electrical connector, it can potentially affect electrical contact.

Can P0985 Cause Limp Mode?

Yes.

Depending on the transmission design, the TCM may enter a protective mode when it cannot control Shift Solenoid “E” correctly.

Possible results include:

• Limited gears

• Fixed gear operation

• Harsh shifting

• Delayed engagement

• Increased line pressure

• Reduced transmission functionality

Not every vehicle with P0985 will enter limp mode.

The exact response depends on the vehicle's transmission and control software.

Can P0985 Damage the Transmission?

P0985 itself does not automatically mean that transmission damage has occurred.

However, if the solenoid controls an important clutch or hydraulic circuit and the transmission continues operating incorrectly, abnormal shifting can increase:

• Clutch wear

• Heat

• Hydraulic stress

• Internal component wear

For this reason, the underlying fault should be diagnosed promptly.

Common Diagnostic Mistakes With P0985

One of the most common mistakes is immediately replacing Shift Solenoid “E.”

The actual problem could be a short to ground, damaged wiring or a poor connector.

Another mistake is interpreting “Circuit Low” as “transmission pressure is low.”

P0985 is primarily an electrical code.

Another common mistake is replacing the transmission without first performing basic electrical tests.

P0985 alone does not prove that the transmission needs to be rebuilt or replaced.

What Is the Correct Repair for P0985?

The correct repair depends on the confirmed cause.

Possible repairs include:

• Replacing Shift Solenoid “E”

• Repairing damaged wiring

• Removing a short to ground

• Repairing an open circuit

• Replacing damaged connector terminals

• Cleaning or replacing a contaminated connector

• Restoring the correct solenoid power supply

• Repairing the solenoid control circuit

• Correcting poor electrical connections

• Repairing valve-body problems when confirmed

• Repairing internal hydraulic problems when confirmed

• Repairing or replacing the TCM when it is conclusively diagnosed as faulty

Final Thoughts on P0985

P0985 – Shift Solenoid “E” Control Circuit Low indicates that the transmission control module has detected an electrically low condition in the Shift Solenoid “E” control circuit.

The most important areas to investigate are the solenoid, wiring, connectors, power supply and control circuit.

A short to ground, damaged wire or poor connector can produce P0985 even when the solenoid itself is perfectly functional.

It is also important to remember that P0985 does not automatically mean that transmission fluid pressure is low or that the transmission has suffered internal mechanical damage.

A systematic diagnosis should begin with the electrical circuit. If the electrical system passes inspection, the technician can then investigate the solenoid's mechanical operation, valve body and hydraulic system.

Diagnosing the circuit before replacing parts is the best way to repair P0985 correctly and avoid unnecessary transmission or solenoid replacement.