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2021 Crosstrek Transmission Jerking and P0700 Code

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Ashley M. · rep 0 · May 22, 3:13 AM · 1 replies · solved · Question

Vehicle: 2021 Subaru Crosstrek Limited

Hello everyone,

I'm experiencing a worrying issue with my 2021 Subaru Crosstrek Limited (CVT transmission). Over the past few days, I've noticed the transmission occasionally jerking or feeling like it's slipping, especially during light acceleration or when coming to a stop. Today, the Check Engine Light came on, and when I scanned it, I got a P0700 code: 'Transmission Control System Malfunction'.

I know the P0700 is a generic code that just tells me the Transmission Control Module (TCM) has detected a fault, but it doesn't specify what. I'm really concerned about the CVT, as I've heard they can be expensive to repair. The car has about 45,000 miles on it.

Has anyone with a newer Crosstrek or other Subaru CVT experienced similar symptoms and this code? What was the underlying issue? I'm trying to understand if this is a sensor problem, low fluid, or something more serious with the transmission itself.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:13 AM

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ClearTheCode admin answer:

The P0700 code on your 2021 Subaru Crosstrek Limited, combined with jerking and slipping sensations, is a clear indicator that your Transmission Control Module (TCM) has detected a fault within the Continuously Variable Transmission (CVT) system. This code is a general informational code, meaning there are more specific trouble codes stored within the TCM that your standard OBD-II scanner might not be able to access.

Here's what this could mean and what steps to consider:

  1. Check Transmission Fluid Level and Condition: While Subaru CVTs are often considered 'sealed for life,' checking the fluid level (if a dipstick is present, or via inspection port) and condition (color, smell) is a crucial first step. Low or degraded fluid can cause slipping and jerking.
    • Action: Consult your owner's manual or a Subaru service guide for the correct procedure to check CVT fluid. Note that many newer Subarus require specific tools and procedures for this.
  2. Specific TCM Codes: The P0700 code is a request from the TCM to the Engine Control Module (ECM) to turn on the Check Engine Light. There will be one or more manufacturer-specific codes (e.g., P27xx, P07xx) stored in the TCM that pinpoint the exact issue.
    • Action: A professional-grade scan tool (like those used by dealerships or advanced independent shops) is needed to read these specific TCM codes. These codes will guide the diagnosis significantly.
  3. Common CVT Issues (leading to P0700):
    • Valve Body Malfunction: Issues with the valve body can affect fluid pressure and flow, leading to shifting problems.
    • Torque Converter Lock-up Issues: Problems with the torque converter engaging or disengaging can cause jerking.
    • Speed Sensor Malfunctions: Faulty input or output speed sensors can confuse the TCM, leading to incorrect gear ratios or slipping.
    • Internal Component Wear: While less common on a 2021 model with 45k miles, internal wear of the belt or pulleys can occur.
    • Wiring/Connector Issues: Damaged wiring or loose connectors to the TCM or transmission sensors can cause intermittent faults.

When to see a shop: Given the symptoms (jerking, slipping) and the P0700 code, it is critical to have your 2021 Subaru Crosstrek inspected by a Subaru dealership or a reputable transmission specialist as soon as possible. Driving with these symptoms can potentially exacerbate the problem and lead to more severe and costly damage to the CVT. They have the necessary diagnostic equipment to read the specific TCM codes, perform advanced tests, and accurately diagnose the underlying issue. Do not delay this inspection.

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