P0985 — Shift Solenoid « E » Control Circuit Low

The diagnostic trouble code P0985 indicates an issue with the shift solenoid « E » control circuit being in a low or open state. Essentially, this means that the vehicle’s transmission control module (TCM) or engine control unit (ECU) detects a problem with the electrical signal sent to or from the specific shift solenoid responsible for managing gear shifts in your automatic transmission. Keep in mind that the labeling of this code might vary depending on the vehicle manufacturer.

Fast Facts

System affected: Transmission control system (automatic transmission)
Severity: Moderate — requires diagnosis and repair but typically not immediate
Main symptoms: Transmission shifting issues, warning lights, reduced drivability
Driveability: Limited — vehicle may still be drivable but with noticeable shifts or performance problems

Manufacturer variations for trouble code P0985

Depending on the vehicle’s make and model, the manufacturer may assign different label codes for the same diagnostic issue. While P0985 is a standard OBD-II code, some OEMs may have their own variations or sub-labels that appear on their diagnostic systems or specific vehicle dashboards. It is essential to refer to the manufacturer’s technical documentation for precise interpretation. Some known label variations include:

Ford: Shift Solenoid « E » Control Circuit Low
Honda: Shift Solenoid E Circuit Low
Volkswagen: 002985—Transmission shift solenoid E – Circuit malfunction
BMW: Transmission Control Module (TCM) – Solenoid E Circuit Low

What does trouble code P0985 mean?

To understand P0985, it’s helpful to know what the transmission control system does. This system manages gear shifting automatically by controlling shift solenoids, which are electrically operated valves that regulate transmission fluid flow and gear engagement. The ECU or TCM monitors the electrical signals sent to these solenoids, ensuring proper communication and operation.

The code P0985 triggers when the ECU detects a low voltage or open circuit in the control circuit of the shift solenoid « E ». This could be caused by a wiring issue, a faulty solenoid, or a problem within the transmission itself. Usually, this code appears when the vehicle is shifting gears unevenly, or if the transmission is stuck in a certain gear or failing to shift altogether.

Severity and risks of trouble code P0985

The presence of P0985 can potentially lead to transmission shifting problems, reduced driving comfort, and further damage if not addressed promptly. Typical risks include gear slipping, hard or delayed shifts, or even transmission failure in extreme cases. However, in many instances, the vehicle is still drivable, but with diminished performance. It is recommended to diagnose and repair this issue promptly to prevent escalation.

Conclusion: Limited — the vehicle can usually still be driven, but driving with this fault is not advisable for the long term.

Symptoms of trouble code P0985

When P0985 is active, drivers might notice various symptoms indicating transmission health issues. These symptoms can range from minor inconveniences to more serious performance problems. Typical signs include:

Unusual or harsh shifting of gears
Transmission stuck in a single gear (commonly 3rd or neutral)
Delayed gear engagement or slippage during acceleration
Transmission warning light or check engine light illuminated
Decrease in fuel efficiency due to improper shifting
Erratic or inconsistent acceleration response

Most likely causes of trouble code P0985

This fault code is generally caused by electrical or mechanical issues within the transmission’s control circuit. Diagnosing the root cause involves examining wiring, connectors, and the solenoid itself. The most common causes include:

Faulty shift solenoid « E » – The solenoid may be defective or worn out, preventing it from responding correctly to signals.
Damaged or corroded wiring or connectors – Electrical connections that are loose, corroded, or broken can interrupt signals.
Electrical control circuit issues – Problems like blown fuses, relay faults, or wiring shorts can impair communication.
Transmission control module (TCM) or ECU malfunction – Rare but possible, if the control unit isn’t functioning correctly, it may send erroneous signals.
Internal transmission mechanical failure – Less common, but sometimes internal issues can affect the solenoid circuit indirectly.

How to diagnose trouble code P0985

Diagnosing P0985 involves verifying the electrical circuit and ensuring the transmission components are functioning correctly. Here are some generic steps:

Visual Inspection: Check wiring harnesses, connectors, and the solenoid for obvious damage, corrosion, or disconnection.
Check Fuses and Relays: Ensure all related fuses and relays are intact and functioning properly.
Live Data Reading: Using a diagnostic scanner, observe the transmission control module’s live data. Verify if the control circuit for solenoid « E » shows low or no voltage when commanded.
Continuity Tests: Test wiring continuity from the ECU to the solenoid to detect open circuits or shorts.
Solenoid Testing: If possible, bench test the shift solenoid « E » for proper operation or replace it if suspected faulty.
Scan for Additional Codes: Check for other transmission-related fault codes that may provide clues to underlying issues.

Possible repairs for trouble code P0985

Addressing P0985 usually involves catering to the identified cause. Some potential repairs include:

Replacing the shift solenoid « E » – When the solenoid itself is defective, a professional replacement is recommended.
Repairing or replacing damaged wiring or connector – Restoring proper electrical connections is often a straightforward, sometimes DIY-friendly task.
Checking and replacing blown fuses or relays – Simple repair steps that can resolve circuit issues.
ECU or TCM reprogramming or replacement – Occasionally needed if the control module is malfunctioning, best handled by a professional.
Internal transmission repairs – If internal damage is detected, more extensive overhaul may be required, often performed by specialists.

Vehicles commonly associated with trouble code P0985 in Europe

While this fault can occur across various makes and models, certain vehicle types are more frequently impacted. Automakers known to report P0985 include:

Ford: Various models with automatic transmissions
Honda: Several recent models with CVT or traditional automatics
Volkswagen: Multiple models from various engine families
BMW: Automatic transmissions in certain series

It’s essential to consult specific technical data for each vehicle, as the exact affected models and engine configurations can differ widely.

Frequent mistakes with trouble code P0985

Diagnosing and repairing transmission issues like P0985 requires careful attention. Common mistakes include:

Assuming the problem is solely electrical without inspecting the solenoid physically
Replacing parts without proper testing, leading to unnecessary repairs
Overlooking wiring issues or corrosion that may be hidden behind panels
Ignoring calibration or reprogramming needs after part replacement
Failing to check for related codes that could indicate root causes elsewhere in the system

FAQ — trouble code P0985

Can this code disappear on its own?
In some cases, if the issue was caused by a temporary glitch or loose connection, clearing the code might lead to its temporary disappearance. However, without fixing the underlying problem, it will likely return.

Can I keep driving?
While it is possible to drive with this code, it is not recommended. The vehicle’s transmission may experience shifting issues or further damage, which could lead to costly repairs.

Why does the code return after clearing?
The fault reappears because the root cause—such as wiring damage, a faulty solenoid, or control module issue—remains unresolved. Diagnosis and proper repair are necessary to permanently eliminate the code.