P0730 Transmission gear ratio does not match the selected gear

Incorrect gear ratio

P0730 in short

P0730 means the transmission computer compared input and output speeds and the ratio did not match the gear it selected, so something is slipping or misreading. Causes range from software to internal wear. Have it inspected soon, and check for a bulletin before agreeing to a rebuild.

The computer knows which gear it has selected and what the ratio between input and output shaft speed should be in that gear. If the measured ratio does not match, it sets P0730. Unlike P0731 to P0736, this code does not say which gear.

A slipping clutch or band, low or worn fluid pressure, or a faulty speed signal can all upset the ratio. Honda tied it to a Civic that would not move in Drive, and Ford issued a gear ratio bulletin for some 2003–2004 TorqShift trucks.

Sometimes software is the answer. Chrysler reflashed some 2012 vehicles because P0730 set when it should not have, and GM says the code can set falsely during transport on new 2019–2020 Malibus. A bulletin check by VIN comes first.

Most likely causes

  1. Transmission computer software setting the code falsely (2012 Chrysler, Dodge, Jeep)

    Supported by vehicle data
    Why it ranks here
    Chrysler reflashes the transmission computer on these 2012 vehicles because P0730 could set erroneously or with limp-in.
    What would change this
    Rises on a covered 2012 vehicle that has not had the flash.
    How to test the transmission control module (tcm)

  2. Internal slipping from worn clutches, bands or low pressure

    Possible — needs testing
    Why it ranks here
    A real ratio error means the transmission is slipping or not applying a gear, which bulletins link to a car that will not move in Drive.
    What would change this
    Rises if the engine flares between shifts, the car will not move in gear, or the fluid is burnt or low.

  3. Wrong or missing speed sensor signal

    Possible — needs testing
    Why it ranks here
    The ratio is worked out from speed sensor readings, and a bad speed signal makes a healthy gear look wrong.
    What would change this
    Rises if input or output speed sensor codes are also stored.

  4. False code from vehicle transport (2019–2020 Malibu)

    Supported by vehicle data
    Why it ranks here
    GM says P0730 can set during transport and is false unless the customer reports the MIL and other codes are present.
    What would change this
    Rises on a new Malibu with the code stored in history and no MIL.

What to test first

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

  1. Read codes from the engine and transmission modules with a scan tool that supports both, before anything is cleared.

    Low riskTool: scan tool that reads the transmission module

  2. Check for a P0730 bulletin for your VIN at a dealer or on the NHTSA site.

    Low risk

  3. Have a transmission shop check fluid level and condition, then road-test while watching commanded gear and input and output speeds.

    Best left to a shopTool: scan tool with transmission data

    Warning:Shop test. Many transmissions have no dipstick and need the maker's fluid check procedure, and the road test needs live data.

Symptoms

  • Check engine light
  • Slipping, flaring or harsh shifts
  • Car will not move when Drive is selected (some Civics) Gets more serious: stop and have it checked.
  • Transmission indicator flashing "D" on some Hondas Gets more serious: stop and have it checked.
  • Transmission stuck in one gear or reduced power (limp-in mode) Gets more serious: stop and have it checked.

Compare with: Check engine light with loss of power

How to fix

  1. Do not clear the code before the transmission module has been read.

  2. Ask a dealer whether your VIN has an open P0730 bulletin before agreeing to a rebuild. Chrysler, GM, Honda and Ford have issued them.

Parts and cost context

  • Transmission control module (TCM):Several P0730 fixes are software updates to the transmission computer, not new hardware. Replacing the module itself is rarely the answer unless a test points to it.

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

Compare used part prices on PartPriceGuide

On your vehicle

Honda

  • 2001–2004 · Civic

    Supported by vehicle data

    Honda 04-036 covers Civics that cannot move in Drive, with the MIL on or D blinking and P0730 stored. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • 04-036Status unverified

    Car cannot move in Drive; MIL on or D blinks with P0730

    2001–2004civic · issued · NHTSA 10010754

    Covers 2001–2004 Civics that will not move when Drive is selected, with the MIL on or the D indicator blinking and P0730 stored. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

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

Dodge

  • 2012 · Charger

    Supported by vehicle data

    Chrysler 21-005-13 and 21-033-14 reflash the transmission computer for the MIL and/or limp-in with P0730, including cases where it set erroneously. Challenger, Durango, 300 and Jeep Grand Cherokee and Wrangler are also covered. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • 21-005-13Status unverified

    Flash: MIL with P0730 incorrect gear ratio

    2012charger, challenger, durango · issued · NHTSA 10136856

    Transmission computer software update for the MIL and/or limp-in with P0730. Chrysler 300C and Jeep Grand Cherokee and Wrangler are also listed. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

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

Chevrolet

  • 2019–2020 · Malibu

    Supported by vehicle data

    GM 19-NA-201 says P0730 may set during transport and is false unless the customer reports the MIL and other codes are present. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • 19-NA-201Status unverified

    P0730 set during vehicle transport

    2019–2020malibu · issued · NHTSA 10166627

    P0730 may set during transport and is considered false unless the customer reports the MIL on and other codes are present. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

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

Ford

  • 2003–2004 · F-250 Super Duty · TorqShift transmission

    Supported by vehicle data

    Ford 17618 covers a gear ratio error with P0730 on TorqShift-equipped Super Duty trucks and Excursion. The bulletin is on NHTSA, but whether it is still current is not verified, so it is labelled vehicle data rather than confirmed.

  • 17618Status unverified

    Transmission gear ratio error P0730

    2003–2004f-250, f-350, excursion · TorqShift transmission · issued · NHTSA 10007400

    Covers P0730 on TorqShift-equipped Super Duty trucks and Excursion. Only the NHTSA flat-file summary was reviewed, not the bulletin itself.

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

  • P0700Transmission module requests the check engine light

    Primary / secondary Possible — needs testing

    Likely primary: P0730. On cars with a separate transmission module, a basic code reader may show only P0700, which means the module has stored its own code. P0730 can be that code, so fix P0730 and P0700 goes with it.

  • P0731Transmission computer sees the wrong speed ratio in first gear

    Same system Possible — needs testing

    P0731 to P0734 are the gear-specific versions of the same ratio check.

  • P0732Transmission computer sees the wrong speed ratio in second gear

    Same system Possible — needs testing

    P0732 is the second-gear version of the same ratio check.

  • P0717No signal from the transmission input or turbine speed sensor

    Shares causes Supported by vehicle data

    On some 2008 Dodge and Jeep models the computer could report P0730 when the real fault was P0717; Chrysler fixed this with a flash.

All Transmission codes

P0730 questions

Does P0730 mean I need a new transmission?

Not necessarily. Chrysler fixed some 2012 vehicles with software, and GM says the code can be false on new Malibus after transport. If the transmission really is slipping, a shop has to test it before deciding on a repair.

How is P0730 different from P0731?

P0731 to P0734 name the gear that has the wrong ratio. P0730 is the general version and does not say which gear.

Sources and review

  1. Toyota Camry Owner's Manual (OM06291U) — Toyota
  2. Honda 04-036: 2001–2004 Civic cannot move in Drive, MIL or blinking D with P0730 — American Honda / NHTSA ,
  3. Chrysler 21-005-13: TCM flash for MIL with P0730 — Chrysler Group / NHTSA ,
  4. Cal. Code Regs. Tit. 13, § 1968.2 — Malfunction and Diagnostic System Requirements (OBD II) — California Air Resources Board (via Cornell LII)
  5. Chrysler 21-033-14: TCM flash for P0730 setting erroneously, shift enhancements — Chrysler Group / NHTSA ,
  6. Ford 17618: TorqShift gear ratio error P0730 — Ford Motor Company / NHTSA ,
  7. Tranny Problems: On the Outside Looking In — MOTOR Magazine ,
  8. Chrysler 21-014-08: flash for incorrect reporting of P0730 for P0717 — Chrysler LLC / NHTSA ,
  9. GM 19-NA-201: P0730 set during vehicle transport — General Motors / NHTSA ,
  10. DTC P0700 — Saab 9-5 (9650) 2010 Workshop Information System — SaabWISOnline (community rehost of Saab/GM service information)
Last reviewed
Written by
Saurabh K.
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