P2681 Engine coolant bypass valve A control circuit open or out of range

Coolant bypass valve circuit

P2681 in short

P2681 means the engine computer found an open or short in the circuit for the engine coolant bypass valve, an electric valve that controls coolant flow. Check coolant level and look for leaks at the valve, then test its wiring and fuse. Several makers have bulletins. Get it checked soon, and stop if the engine overheats.

Many newer engines use an electrically driven valve to steer coolant between the engine, radiator, heater and other loops. It helps the engine warm up faster and control temperature more precisely.

The engine computer drives the valve and watches the circuit. P2681 sets when it sees an open circuit, a short or a voltage that does not match what it commands. Toyota adds a suffix: P268111 for a short to ground and P268115 for a short to battery or an open.

On 2018-2021 Toyota four-cylinder engines the valve itself can crack and leak, and coolant dripping onto the connector can trigger the code along with an 'Engine Maintenance Required' message. On other makes the cause is more often wiring, a blown fuse or software.

Most likely causes

  1. Cracked or leaking coolant bypass valve (Toyota 2.0L/2.5L)

    Supported by vehicle data
    Why it ranks here
    Toyota runs a support program for a leaking flow shut-off valve on many 2018-2021 models and a bulletin for P2681 with 'Engine Maintenance Required' on the same engines; owners report cracked valve housings with this code.
    What would change this
    Rises on a listed Toyota with coolant residue at the valve or a falling coolant level; falls if the valve and connector are dry.

  2. Damaged wiring, connector or blown fuse in the valve circuit

    Common general cause
    Why it ranks here
    A circuit code is set by anything that opens or shorts the circuit. Ford traced P2681 with other codes on 2017-2019 Escapes to a chafed harness blowing fuse F34, and bypass valve wiring and connectors are a common cause on Ford valves.
    What would change this
    Rises if a fuse is blown, the connector is corroded or wet, or several unrelated codes set together.
    How to test the underhood fuse block (engine compartment fuse box)

  3. Broken internal valve gear (2022-2023 Ram 1500)

    Supported by vehicle data
    Why it ranks here
    FCA's bulletin for a broken internal gear in the three-way coolant valve lists P2681 alongside P26A3 and P26A6, and replaces the valve.
    What would change this
    Applies to the listed trucks; rises when P26A3 or P26A6 are stored with P2681.

  4. Engine computer software (some models)

    Supported by vehicle data
    Why it ranks here
    FCA (2016-2017 Durango and Grand Cherokee 3.6L) and Volkswagen (2024 Atlas) address P2681 with an engine computer update.
    What would change this
    Rises if a bulletin covers your vehicle and the update has not been done.
    How to test the engine control module (ecm / pcm)

What to test first

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

  1. With the engine fully cold, check the coolant level and look around the bypass valve and its hoses for wet spots, dried coolant crust or a sweet smell.

    Low riskTool: flashlight

  2. With the ignition off, check the fuse that feeds the valve and inspect the valve connector and harness for corrosion, coolant contamination, chafing or loose pins.

    Low riskTool: wiring diagram, fuse puller, flashlight

  3. Have a shop check for bulletins, then command the valve with a scan tool and measure its circuit against the service information.

    Best left to a shopTool: scan tool with active tests, multimeter, service information

    Warning:Valve tests may need the engine warm and running, near hot coolant and moving parts. Leave this to a shop.

Symptoms

  • Check engine light
  • 'Engine Maintenance Required' message (Toyota)
  • Heater or A/C not working normally
  • Coolant level dropping or sweet coolant smell
  • Temperature gauge rising or overheating warning Gets more serious: stop and have it checked.

How to fix

  1. Write down every stored code and the freeze-frame data before clearing anything.

  2. With the engine fully cold, check the coolant level in the reservoir and top up with the coolant type the owner's manual specifies if it is low; a level that keeps dropping means a leak to find.

    Warning:Never open the radiator cap or pressurised reservoir while the engine is hot.

  3. Ask a dealer whether a bulletin or support program covers your vehicle before paying for a valve; several makers have them for this code.

Parts and cost context

  • Engine control module (ECM / PCM):Software updates are done by a dealer; check for one before replacing the valve on covered vehicles.

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

Compare used part prices on PartPriceGuide

On your vehicle

Toyota

  • 2019–2021 · RAV4

    Supported by vehicle data

    Toyota has a support program for a leaking flow shut-off valve and a bulletin for P2681 with 'Engine Maintenance Required' on these years. Owners report cracked valves; ask a dealer about 24TE04 and T-SB-0112-24.

  • 2019–2021 · Corolla

    Supported by vehicle data

    Covered by Toyota's flow shut-off valve support program and bulletin on certain cars. Owners report P2681 with a cracked bypass valve case.

  • 2018–2021 · Camry

    Supported by vehicle data

    Toyota's support program and bulletin for the coolant bypass (flow shut-off) valve include the Camry and Camry Hybrid. Ask a dealer before paying for a valve.

  • 24TE04Status unverified

    Toyota CSP 24TE04: flow shut-off valve coolant leak

    2018–2021rav4, corolla, camry, avalon, highlander, sienna, venza · issued · NHTSA 11012726

    A small coolant leak from a specific valve can drip on other parts, show 'Maintenance Required' or upset the A/C. Covered vehicles get a new flow shut-off valve. NHTSA's summary does not name a trouble code; coverage varies by model and year.

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

  • T-SB-0112-24Status unverified

    Toyota T-SB-0112-24: Engine Maintenance Required with P268111/P268115

    2018–2021rav4, corolla, camry, avalon, highlander, sienna, venza · A25A-FKS, A25A-FXS, M20A-FKS · issued · NHTSA 11012731

    Some 2018-2021 Toyota vehicles with A25A or M20A engines show 'Engine Maintenance Required' with P268111 or P268115 (coolant bypass valve circuit). Revision 1 was published in January 2025.

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

Ford

  • 2017–2019 · Escape · 1.5L, 2.0L

    Supported by vehicle data

    On the 1.5L and 2.0L, P2681 with several unrelated codes and a blown fuse F34 points to a chafed PCM harness (SSM 48895).

  • SSM 48895Status unverified

    Ford SSM 48895: fuse F34 open with P2681 and other codes

    2017–2019escape · 1.5L, 2.0L · issued · NHTSA 10176943

    On 2017-2019 Escape 1.5L and 2.0L, a chafed harness between the battery junction box and the PCM can blow fuse F34 and set P2681 with several other codes and AWD or traction warnings. Repair the wiring.

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

Jeep

  • 2016–2017 · Grand Cherokee · 3.6L

    Supported by vehicle data

    On the 3.6L, FCA addresses P2681 as part of a PCM reprogram (18-024-17).

  • 18-024-17 REV. CStatus unverified

    FCA 18-024-17: PCM flash, includes P2681 (3.6L)

    2016–2017grand-cherokee · 3.6L · issued · NHTSA 10121814

    A PCM reprogram for many diagnostic enhancements; FCA lists P2681 Engine Coolant Bypass Valve Control Circuit Open for the 3.6L. Also covers the 2016-2017 Dodge Durango.

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

Dodge

  • 18-024-17 REV. CStatus unverified

    FCA 18-024-17: PCM flash, includes P2681 (3.6L)

    2016–2017grand-cherokee · 3.6L · issued · NHTSA 10121814

    A PCM reprogram for many diagnostic enhancements; FCA lists P2681 Engine Coolant Bypass Valve Control Circuit Open for the 3.6L. Also covers the 2016-2017 Dodge Durango.

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

Ram

  • 2022–2023 · 1500

    Supported by vehicle data

    With P26A3, P26A6 or P2681, FCA replaces the 3-way coolant valve for a broken internal gear (07-005-24).

  • 07-005-24Status unverified

    FCA 07-005-24: broken internal coolant valve gear

    2022–20231500 · issued · NHTSA 11001237

    With P26A3, P26A6 or P2681 set, the 3-way coolant valve is replaced because of a broken internal gear.

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

Volkswagen

  • V0124062074939Status unverified

    VW: ECM update for P00B7, P0116 or P2681

    2024atlas · issued · NHTSA 11007392

    2024 Atlas and Atlas Cross Sport get an engine computer programming update for these codes.

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

  • P26A3Engine coolant bypass valve A range or performance problem

    Same system Supported by vehicle data

    P26A3 is the bypass valve's position or performance fault. FCA lists both codes for a broken internal valve gear on the Ram 1500.

  • P26B7Engine coolant bypass valve C control circuit open

    Same system Common general cause

    P26B7 is the circuit fault for bypass valve C on engines with more than one valve, mainly Ford.

  • P0217The engine computer has detected an engine over-temperature condition

    Raises severity Possible — needs testing

    If a leaking or stuck valve lets the engine overheat, an engine over-temperature code such as P0217 can follow. Treat that as a stop-driving warning.

All Engine cooling (thermostat) codes

P2681 questions

Is P2681 covered by Toyota?

Toyota's Customer Support Program 24TE04 covers a leaking flow shut-off valve on certain 2018-2021 models, subject to its time and mileage limits. Ask a Toyota dealer with your VIN; one owner reports being refused just past the limit.

Can I keep driving with P2681?

Usually for a short time if the temperature gauge stays normal and the coolant level holds. Check the level when cold, watch the gauge, and stop if it climbs or a warning appears.

Sources and review

  1. Toyota Customer Support Program 24TE04: flow shut-off valve coolant leak — Toyota Motor Sales / NHTSA ,
  2. Toyota T-SB-0112-24: Engine Maintenance Required with P268111/P268115 — Toyota Motor Sales / NHTSA ,
  3. Toyota coolant bypass valve lawsuit dismissed — CarComplaints.com (our reviewed reasoning)
  4. NHTSA complaint ODI 11759760: 2020 Toyota RAV4, P2681-15, failure on the highway — NHTSA Office of Defects Investigation (complaint flat file) ,
  5. 2023 Integra Owner's Manual: How to Handle Overheating — American Honda Motor Co.
  6. Toyota Camry Owner's Manual (OM06291U, 2.5L A25A-FKS / 3.5L 2GR-FKS) — Toyota
  7. 2019 Ranger Workshop Manual 303-03 Engine Cooling 2.3L EcoBoost: Description and Operation (Fail Safe Cooling) — Ford Motor Company
  8. NHTSA complaint ODI 11605698: 2021 Toyota Corolla, P2681(15) with cracked bypass valve case — NHTSA Office of Defects Investigation (complaint flat file) ,
  9. NHTSA complaint ODI 11661352: 2020 Toyota Corolla, scan tool readout P2681 bypass valve circuit open — NHTSA Office of Defects Investigation (complaint flat file) ,
  10. Ford SSM 48895: 2017-2019 Escape fuse F34 open, multiple DTCs including P2681 — Ford Motor Company / NHTSA ,
  11. P26B7: Coolant Bypass Valve C Control Circuit/Open — Kelley Blue Book
  12. FCA 07-005-24: Broken internal coolant valve gear, P26A3/P26A6/P2681 — FCA US / NHTSA ,
  13. FCA 18-024-17 REV. C: PCM flash, powertrain diagnostic and system enhancements — FCA US / NHTSA ,
  14. Volkswagen V0124062074939: ECM update for P00B7, P0116 or P2681 — Volkswagen of America / NHTSA ,
Last reviewed
Written by
Saurabh K.
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