Error code P1778 on cars Nissan - one of the most common problems associated with the operation of an automatic transmission. This signal makes owners nervous Qashqai, X-Trail, Juke and other models, because ignoring it can lead to serious damage. But what exactly is hidden behind this code? Why does it appear and how to react correctly?

Unlike many other errors, P1778 does not always indicate a critical malfunction. Most often, it signals a discrepancy between the actual operation of the transmission and the expected parameters that are included in the control unit. However, without timely diagnostics, even “mild” failures can develop into expensive repairs. In this article we will look at unique features of error P1778 on Nissan with Jatco JF011E/JF015E CVT, which are not covered in standard manuals.

What does error code P1778 mean on Nissan?

Code P1778 stands for "Torque Converter Clutch Solenoid Performance" — a problem with the operation of the torque converter lock-up solenoid. In transmissions Nissan (especially with CVTs Jatco) this solenoid is responsible for smooth switching between locking and unlocking modes of the torque converter. When the control unit (TCM) detects a discrepancy in signals or a delay in response, it activates an error.

It is important to understand that P1778 - this is not an independent breakdown, but symptom. It can appear both due to mechanical problems (solenoid wear, oil contamination) and electronic failures (incorrect data from sensors, problems with firmware TCM). In practice, owners Nissan Qashqai J11 And X-Trail T32 They encounter this error most often after 100–150 thousand kilometers.

  • 🔧 Mechanical reasons: solenoid wear, contaminated oil in the variator, damaged wiring.
  • 📡 Electronic reasons: faults in the control unit TCM, incorrect data from the speed or throttle position sensor.
  • ⚡ External factors: sudden temperature changes, long periods of work in traffic jams, aggressive driving style.
⚠️ Attention: If error P1778 accompanied by jerking when shifting gears or the lamp coming on "Check Engine" paired with code P0740 (torque converter lock-up malfunction), this may indicate critical wear of the variator. In this case, the operation of the car prohibited until the problem is resolved.

P1778 Symptoms: How to Recognize the Problem?

Error P1778 rarely manifests itself - it is usually accompanied by noticeable changes in the behavior of the transmission. Here are the key signs to look out for:

  • 🚗 Jerks during acceleration, especially at speeds of 40–60 km/h.
  • 🔄 Switching delays between "D" and "R" (up to 1–2 seconds).
  • 🌡️ Increase in oil temperature in the variator (can be checked through Nissan Consult or scanner ELM327).
  • 🔊 Extraneous sounds from the torque converter area (hum, grinding noise).

On models with CVT Jatco JF011E (For example, Nissan Juke F15) error P1778 often appears in conjunction with code P0841 — incorrect pressure ratio in the valve body. This combo signals the need for comprehensive diagnostics, since the problem may lie both in the solenoid and in the valve body itself.

Symptom Probable Cause Urgency of repair
Jerks during acceleration Worn torque converter lock-up solenoid Medium (can be used, but no more than 1–2 weeks)
caught fire Check Engine + P1778 + P0740 Critical wear of the torque converter or variator High (operation prohibited)
Increased oil temperature in the variator Contaminated oil or faulty solenoid Medium (oil change and diagnostics required)

If you notice at least one of these symptoms, first check the level and condition of the oil in the variator. On Nissan with CVTs Jatco the oil should be light red in color without a burning smell. Dark color and metal shavings on the dipstick are a direct signal to change the oil and filters.

📊 Which Nissan model are you experiencing error code P1778 with?
  • Qashqai J11
  • X-Trail T32
  • Juke F15
  • Note E12
  • Other model

Causes of error P1778: let's understand the details

To effectively resolve an error, you need to understand its root cause. In practice P1778 arises from three groups of problems:

  1. Torque converter lock-up solenoid malfunction - the most common cause (about 60% of cases). The solenoid may become stuck in the open or closed position, causing it to lock incorrectly.
  2. Problems with oil in the variator — contaminated or old oil impairs the performance of the hydraulic system, which causes failures in the solenoids.
  3. Failures in the control unit TCM — incorrect data from sensors or firmware errors can cause false signals.

By car Nissan Qashqai J11 with variator JF015E error P1778 often appears after changing the oil in the variator, if non-original oil was filled in or adaptation was not made TCM. The fact is that the control unit “gets used” to certain operating parameters of the transmission, and after changing the oil, the adaptations need to be reset.

⚠️ Attention: If you recently added oil to the variator Nissan and immediately an error appeared P1778, do not rush to blame the solenoid. First follow the procedure TCM Reset via a diagnostic scanner (for example, Launch X431 or Nissan Consult III). In 30% of cases this solves the problem without additional repairs.

Another common reason is wiring damage between control unit TCM and solenoid. On Nissan X-Trail T32 the wires often rub against the transmission housing, which leads to a short circuit or signal interruption. Check the integrity of the harness, especially in the area of ​​the solenoid connector.

How to check the torque converter lock-up solenoid without removing it?

For preliminary diagnostics of the solenoid, you can use a multimeter. Connect the probes to the contacts of the solenoid connector (with the ignition off) and measure the resistance. Normal value for most models Nissan — 10–15 Ohm. If the resistance approaches zero or infinity, the solenoid is faulty and requires replacement.

Diagnosing error P1778: step-by-step instructions

For accurate diagnosis P1778 you will need a scanner that supports transmission work Nissan (For example, Launch CReader, Autel MaxiCOM or original Consult III). Here is the algorithm of actions:

Read all error codes (including Pending Codes)

Checking the level and condition of the oil in the variator

Torque Converter Lockup Solenoid Test (Resistance and Control Signal)

Diagnostics of wiring between TCM and solenoid

Checking data from speed and throttle position sensors-->

Let's start by reading the codes. If in addition P1778 there are errors P0700 (transmission malfunction) or P0740 (lockup of the torque converter), this confirms a problem with the solenoid or torque converter. Next:

  1. Check the oil:
    • The level should be between the marks MIN And MAX on the dipstick (check on a warm transmission!).
    • The color of the oil is red or light brown. Black oil with a burning smell is a signal to replace it.
  2. Solenoid test:
    • Remove the connector from the solenoid and check the resistance (normal: 10-15 ohms).
    • Apply 12V voltage to the solenoid - a click should be heard (working solenoid).
  3. Check TCM:
    • Use a scanner to check the parameters Torque Converter Clutch Solenoid Duty Cycle. Normally, the value should fluctuate in the range of 10–90%.
    • If the value is fixed at 0% or 100%, the problem is in the control unit or wiring.

On Nissan Note E12 And Micra K13 with variator JF015E error P1778 sometimes appears due to incorrect operation of the speed sensor. Check its signal through the scanner: the speed should increase smoothly without jumps. Sudden jumps in values ​​(for example, from 40 km/h to 80 km/h in a second) indicate a malfunction of the sensor or its wiring.

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If you don't have a diagnostic scanner, you can use the app Torque Pro with adapter ELM327. It will show the main parameters of the transmission, including oil temperature and torque converter speed. However, to reset errors and adapt TCM professional equipment will be required.

How to fix error P1778: from simple to complex

Repair methods depend on the cause of the error. Let's start with the simplest and cheapest solutions:

1. Changing the oil in the variator

If the oil is contaminated or its level is below normal, perform a complete replacement and flush the valve body. For Nissan with CVTs Jatco original oil recommended NS-3 (article KE909-99932). The volume for a complete replacement is 7–9 liters (depending on the model).

2. Cleaning or replacing the solenoid

If tests show a malfunction of the torque converter lock-up solenoid, you can try cleaning it (in 20% of cases this helps). To do this:

  1. Remove the variator pan.
  2. Remove the solenoid (usually it is located in the valve body).
  3. Wash it in clean gasoline or a special cleaner (for example, Liqui Moly ATF Reiniger).
  4. Check the mobility of the rod - it should move smoothly, without jamming.

If cleaning does not help, the solenoid must be replaced. For Nissan Qashqai J11 the original solenoid has the part number 31726-3MX0A (price ~3–5 thousand rubles).

3. Adaptation of the control unit TCM

After changing the oil or solenoid, be sure to perform an adaptation TCM. Without this error P1778 may come back. The procedure is carried out through a diagnostic scanner:

1. Подключите сканер к разъёму OBD-II.

2. Выберите меню "Transmission" → "TCM Adaptation".


3. Следуйте инструкциям на экране (обычно требуется нажать педаль тормоза и перевести селектор в положение "D").


4. Дождитесь завершения процедуры (заняет 2–5 минут).

4. Repair or replacement of wiring

If the problem is in the wiring, restore the integrity of the harness. On Nissan X-Trail T32 The wires near the solenoid connector often fray. Use heat shrink tubing for insulation and secure the harness with plastic ties to prevent repeated chafing.

⚠️ Attention: If after all the manipulations there is an error P1778 continues to appear, but the solenoid and wiring are fine, the problem may lie in the control unit itself TCM. In this case, it will need to be re-flashed or replaced. On models up to 2015 TCM often fails due to overheating - check the integrity of the unit cooling radiator.
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By car Nissan with CVTs Jatco error P1778 can be eliminated in 80% of cases by changing the oil, cleaning the solenoid and adapting TCM. Only 20% of problems require serious repairs (replacement of the valve body or TCM).

Prevention of error P1778: how to avoid recurrence

To make a mistake P1778 did not return, follow these recommendations:

  • 🔧 Regular oil changes in a variator - every 60–80 thousand km (despite the manufacturer’s statements about a “maintenance-free” variator).
  • 🚗 Avoid aggressive driving: Sharp starts and braking increase the load on the torque converter.
  • 🌡️ Control the temperature: do not allow the variator to overheat (optimal oil temperature is 80–90°C).
  • 🔌 Check the connectors: At least once a year, clean the solenoid contacts and TCM from oxidation.

On Nissan Juke F15 And Qashqai J11 with variator JF015E It is recommended to install an additional oil cooling radiator. This reduces the load on the solenoids and increases transmission life. The cost of the kit (radiator + pipes) is about 10–15 thousand rubles.

Also pay attention to the quality of the oil. Use only original NS-3 or its analogues with approval Nissan Matic-S. Cheap all-purpose oils (for example, Dexron VI) do not provide sufficient protection for the solenoids and lead to their premature wear.

Frequently asked questions about error code P1778 on Nissan

Is it possible to drive with P1778?

Short-term - yes, but no more than 1-2 weeks. Driving for a long time with this error leads to accelerated wear of the torque converter and solenoids. If the error is accompanied by jerking or burning Check Engine, operation prohibited.

How much does it cost to repair error code P1778?

The cost depends on the reason:

  • Oil change - 3-5 thousand rubles.
  • Cleaning/replacing the solenoid - 5–10 thousand rubles.
  • Adaptation TCM — 1–2 thousand rubles.
  • Wiring repairs - 2–4 thousand rubles.
  • Replacement TCM — 20–40 thousand rubles (depending on the model).

Can P1778 appear after changing the CVT oil?

Yes, this is a common situation. Reason: adaptation not made TCM or low-quality oil was poured. Solution: reset the adaptations through a scanner and make sure the oil is original.

Which Nissan models are most susceptible to P1778?

Most often the error occurs on:

  • Nissan Qashqai J11 (2014–2020) with CVT JF015E.
  • Nissan X-Trail T32 (2014–2021).
  • Nissan Juke F15 (2014–2019).
  • Nissan Note E12 (2012–2016).

On these models CVTs Jatco have design features that predispose them to problems with solenoids.

Is it possible to reset P1778 without a scan tool?

Technically yes - by disconnecting the battery terminal for 10-15 minutes. However, this will not eliminate the cause of the error, and it will return. A full reset requires a scanner with an adaptation function TCM.