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P085C OBD2: Gear Shift Control Module "B" Communication Circuit High

P085C OBD2: Gear Shift Control Module “B” Communication Circuit High

The P085C OBD-II code is a diagnostic trouble code that indicates a problem with the communication between the Transmission Control Module (TCM) and the engine computer (PCM). This code is often triggered when the TCM fails to properly communicate with the PCM, which is essential for optimal vehicle performance.

What Does the P085C Code Mean?

When the P085C code is set, it signifies that there is a high voltage present in the Gear Shift Control Module “B” communication circuit. This communication is vital for the transmission to shift properly and for the overall functionality of the vehicle.

What Causes the P085C Code?

The P085C code can be caused by several factors, including:

  • Powertrain Control Module (PCM) failure
  • Transmission Control Module (TCM) failure
  • Wiring issues leading to poor communication

What Are the Symptoms of the P085C Code?

Drivers may experience a range of symptoms when the P085C code is present, including:

  • Transmission may not shift properly
  • Engine may not start

How Serious Is the P085C Code?

The severity of the P085C code is classified as urgent. It indicates a malfunction that can lead to significant damage not only to the transmission but also to the overall vehicle if not addressed promptly. Additionally, it poses potential safety risks for the driver and passengers.

How to Diagnose the P085C Code

Diagnosing the P085C code typically involves the following steps:

  1. Utilizing an OBD-II scanner to confirm the presence of the P085C code.
  2. Inspecting the wiring and connectors related to the TCM and PCM for any signs of damage or corrosion.
  3. Testing the TCM and PCM for proper functionality.
  4. Checking for additional trouble codes that may indicate other underlying issues.

Common Repairs for the P085C Code

Repairs for the P085C code may include:

  • Replacing the Transmission Control Module (TCM)
  • Replacing the Powertrain Control Module (PCM)
  • Repairing or replacing damaged wiring or connectors

How Much Does It Cost to Fix the P085C Code?

The cost to repair the P085C code can vary widely depending on the cause and the make and model of the vehicle. On average, repairs can range from $100 to $1,500. A simple wiring fix may be inexpensive, while a TCM or PCM replacement could be more costly.

Can I Fix the P085C Code Myself?

While some aspects of diagnosing and fixing the P085C code may be attempted by a knowledgeable DIYer, it is recommended to seek professional assistance. A proper diagnosis requires specialized tools and expertise, and incorrect repairs can lead to further issues.

About JC Landry

JC is the Senior Editor at eManualOnline.com, GarageSpot.com, and Drive-My.com, as well as the Webmaster of TheMechanicDoctor.com, only to name a few. He's been a certified Master Mechanic for 15 years, working for various car dealers and specialized repair shops before turning towards blogging about cars and EVs in the hope of helping the next generation of automotive technicians. He also loves cats, Johnny Cash and Subarus.

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