U0402 A module received invalid data from the transmission computer

Invalid / implausible data received from TCM

U0402 in short

U0402 means a module, usually the engine computer, received data from the transmission computer that it rejects. Software is a common fix on FCA vehicles, followed by transmission faults and wiring. Get it checked soon, because it can come with limp mode or a transmission that will not shift; stop if it loses drive.

The engine computer and transmission computer constantly exchange data such as gear, torque requests and fault status. If a value from the transmission computer is missing, out of range or flagged as faulty, the receiving module stores U0402.

FCA calls this "implausible data received from TCM". Its bulletins mostly update the engine or transmission computer software on Ram 1500, Wrangler, Cherokee, Renegade, Chrysler 200 and Pacifica, and one replaces the valve body on 2023-2025 Grand Cherokee and Wagoneer.

Because the transmission computer may be reporting its own problem, check for transmission codes alongside U0402.

Most likely causes

  1. Engine or transmission computer software that needs an update

    Supported by vehicle data
    Why it ranks here
    Many FCA bulletins (Ram 1500, Wrangler, Cherokee, Renegade, Chrysler 200, Pacifica) treat U0402 with a computer software update.
    What would change this
    Rises if a dealer finds an update for your VIN. Falls if the software is current.

  2. A transmission fault the transmission computer is reporting (valve body or internal)

    Supported by vehicle data
    Why it ranks here
    FCA 21-016-25 replaces the valve body for U0101/U0402 on 2023-2025 Grand Cherokee and Wagoneer, and Land Rover logs U0402 with a gearbox that will not shift from Park.
    What would change this
    Rises if transmission codes are stored too or the transmission shifts badly. Falls if the transmission is code-free and shifts normally.
    How to test the transmission control module (tcm)

  3. Network wiring, connector or low voltage corrupting messages

    Possible — needs testing
    Why it ranks here
    Network wiring and power faults are a common general cause of U-codes, but the bulletins for U0402 point to software and transmission faults more often.
    What would change this
    Rises if lost-communication codes are stored too. Falls if bus resistance and battery voltage are normal.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Scan all modules and note which module stored U0402 and any transmission codes.

    Low riskTool: scan tool that reads all modules

  2. Ask a dealer whether your VIN has a software update or bulletin for U0402. FCA has issued many.

    Low risk

  3. Test the battery and have the network wiring and transmission connector checked.

    Best left to a shopTool: multimeter, battery tester

    Warning:Transmission connectors are under the car near hot parts. Let a shop do it.

Symptoms

  • Check engine light
  • Transmission in limp mode or not shifting
  • Shifter stuck in Park or a gearbox fault message
  • Lack of power or vibration
  • Transmission loses drive while moving Gets more serious: stop and have it checked.

How to fix

  1. Ask a dealer whether your VIN has an open software update for U0402.

  2. Have the 12-volt battery tested.

Parts and cost context

  • Transmission control module (TCM):Software updates fix many U0402 cases on FCA vehicles; check before buying parts. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ram

  • 2022–2023 · 1500

    Supported by vehicle data

    FCA S2221000001 and 1805023: U0402 with MIL, limp mode or no shifting; the 2023 bulletin updates the powertrain computer. Whether the bulletins are still current is not verified.

  • S2221000001Status unverified

    MIL on, U0402 implausible data received from TCM

    20221500 · issued · NHTSA 10227987

    Service information for a Ram 1500 with the MIL on and possibly no shifting, stuck in gear, limp mode, lack of power or vibration with U0402.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 1805023Status unverified

    PCM update for U0402-00

    20231500 · issued · NHTSA 10236940

    Updates the powertrain computer software when the MIL is on with U0402-00.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Jeep

  • 2021 · Wrangler

    Supported by vehicle data

    FCA 18-012-23 updates the powertrain computer for U0402-00. Whether the bulletin is still current is not verified.

  • 2023–2025 · Grand Cherokee

    Supported by vehicle data

    FCA 21-016-25 replaces the valve body for U0402 or U0101 (also Grand Cherokee L, Wagoneer, Grand Wagoneer). Whether it is still current is not verified.

  • 18-012-23Status unverified

    PCM update for U0402-00

    2021wrangler · issued · NHTSA 10231804

    Updates the powertrain computer software when the MIL is on with U0402-00 or related codes.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 21-016-25 REV. CStatus unverified

    Valve body replacement for U0101 or U0402

    2023–2025grand-cherokee, grand-cherokee-l, wagoneer, grand-wagoneer · issued · NHTSA 11022007

    Replace the valve body when the MIL is on with U0101 or U0402.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Land Rover

  • 2014 · Range Rover Sport

    Supported by vehicle data

    Land Rover LTB00677NAS1: transmission will not shift from Park with a Gearbox Fault message, U0001-81 and U0402-2A. Whether it is still current is not verified.

  • LTB00677NAS1Status unverified

    Transmission unable to shift from Park, Gearbox Fault message

    2014range-rover-sport · issued · NHTSA 10101662

    Service information for a Range Rover Sport that will not shift from Park with U0001-81 and U0402-2A stored.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • U0101Lost communication with the transmission computer

    Shares causes Supported by vehicle data

    FCA's valve body bulletin covers U0101 and U0402 together on 2023-2025 Grand Cherokee and Wagoneer.

  • U0401A module received invalid data from the engine or powertrain computer

    Same system Supported by vehicle data

    Ford's Fusion and MKZ blind-spot bulletin covers U0401 and U0402 together in the side object detection modules.

All Module network (CAN bus) communication codes

U0402 questions

Is U0402 a transmission problem?

Sometimes. It means the data from the transmission computer was rejected. FCA often fixes it with a software update, but some cases are a real transmission fault.

Sources and review

  1. FCA S2221000001: MIL on, U0402 implausible data received from TCM — FCA US LLC / NHTSA ,
  2. Land Rover LTB00677NAS1: Transmission unable to shift from Park, Gearbox Fault message — Jaguar Land Rover North America / NHTSA ,
  3. 2023 Integra Owner's Manual: Indicators — American Honda Motor Co.
  4. FCA 1805023: PCM update for U0402-00 — FCA US LLC / NHTSA ,
  5. FCA 18-012-23: PCM update for U0402-00 — FCA US LLC / NHTSA ,
  6. FCA 21-016-25 REV. C: Valve body replacement for U0101 / U0402 — FCA US LLC / NHTSA ,
  7. ASE L1 study guide: Network U-codes — Open Exam Prep
  8. Ford ASI-44656: BLIS/CTA faults with U0401 and/or U0402 in the side object detection modules — Ford Motor Company / NHTSA ,
Last reviewed
Written by
Saurabh K.
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