Error code P1778 on Nissan Murano: a complete analysis of the transmission problem

If on your dashboard Nissan Murano the indicator came on Check Engine, and the scanner issues a code P1778, this is a signal of serious problems with the transmission. This error is directly related to the operation Torque Converter Lockup Solenoid (TCC) - a critical component of the automatic transmission. It cannot be ignored: the consequences can vary from jerks when switching to complete failure of the automatic transmission.

In this article we will look in detail at what is hidden behind the code. P1778why does he appear on Murano (including models Z50, Z51, Z52), how to correctly diagnose a malfunction and what steps to take to repair it. We will pay special attention typical mistakes of owners when trying to “reset” the code without eliminating the cause - this often leads to aggravation of the problem.

What does error code P1778 mean on Nissan Murano?

Code P1778 stands for "Torque Converter Clutch Solenoid Circuit Malfunction" — malfunction in the torque converter lock-up solenoid circuit. This solenoid is responsible for smoothly engaging/disengaging the torque converter clutch, which physically connects the engine and gearbox at high speeds (usually 60–80 km/h). When the solenoid fails or the circuit is broken, the transmission ECU records an error.

In practice this looks like this:

• 🔴 Jerks during acceleration (especially at speeds of 60–100 km/h).
• 🔴 Slipping when changing gears (a feeling of the clutch “slipping”).
• 🔴 Increased speed engine without increasing speed ("dullness").
• 🔴 Transmission overheating (a separate lamp may light up AT TEMP).

Important: on Murano with boxes RE0F10A (until 2010) and JF011E (after 2010) symptoms may vary. For example, in RE0F10A more common mechanical wear of the solenoid, and in JF011E — problems with the wiring or control unit.

⚠️ Attention: Ignoring P1778 will accelerate torque converter clutch wear by 3 to 5 times. In advanced cases, the entire torque converter will need to be replaced (cost from 40,000 ₽).

The main causes of P1778

Error P1778 It never happens “just like that.” Its appearance is always associated with one of the following reasons:

1. TCC solenoid malfunction. The most common problem is a worn or stuck solenoid. On Murano with mileage >150,000 km this occurs in 60% of cases.
2. Wiring problems. Breaks, oxidation of contacts or short circuit in the solenoid circuit (often after unqualified repairs).
3. Malfunction of the automatic transmission control unit (TCM). Less common, but possible - especially after flashes or power surges.
4. Mechanical wear of the torque converter. If the TCC clutch is worn, the solenoid will become overloaded and fail.
5. Contaminated ATF oil. Old or low-quality fluid clogs the valve body channels, which leads to malfunctions of the solenoids.

Diagnosis must begin with a check solenoid resistance (norm for Murano: 10–15 ohms). If it is close to zero or infinity, the solenoid needs to be replaced. Also be sure to check TCM connector voltage (pin 27 - TCC solenoid control).

Diagnosing error P1778: step-by-step instructions

To pinpoint the cause P1778, follow this algorithm. You will need a multimeter, scanner (for example, Launch X431 or ELM327) and basic electrical skills.

Read all errors with a scanner (together with P1778 there may be P0740, P0730)|Check the level and condition of the ATF oil|Measure the resistance of the TCC solenoid (pins 1 and 2 on the connector)|Check the voltage at the TCM connector (pin 27)|Inspect the wiring for breaks and oxidation-->

Step 1: Reading errors. Connect the scanner and record everything fault codes. Often P1778 accompanied by:

• 🔧 P0740 — general TCC malfunction.
• 🔧 P0730 - incorrect gear ratio.
• 🔧 P0715 — malfunction of the input shaft speed sensor.

Step 2. Checking the ATF oil. On Murano there should be oil Nissan Matic-S or Matic-J (depending on the year). If the fluid is black or smells like burning, it requires replacement and flushing. The use of non-original oil accelerates the wear of solenoids by 2 times.

Step 3: TCC Solenoid Test. Remove the automatic transmission pan, find the valve body and disconnect the solenoid connector. Measure the resistance between pins 1 and 2:

Норма: 10–15 Ом
Обрыв: ∞ (бесконечность)
Короткое замыкание: 0 Ом

If the values do not correspond to the norm, the solenoid must be replaced.

Parameter	Normal value	Reason for rejection
TCC Solenoid Resistance	10–15 Ohm	Open or short circuit
Voltage at TCM connector (pin 27)	12 V when ignition is on	Wiring or TCM problems
ATF oil level	Between "HOT" and "COLD" on the dipstick	Leak or overflow
ATF oil color	Red or light brown	Contamination or overheating

⚠️ Attention: If, when checking the solenoid, you find metal shavings in the oil, this is a sign of wear on the torque converter clutch. In this case, the torque converter assembly will need to be replaced.

How to fix error code P1778: repair or replace?

The repair method depends on the cause of the problem. Let's consider all the options:

1. Replace the TCC solenoid. If tests show a faulty solenoid, it must be replaced. On Murano original solenoid is used Nissan 31397-31X00 (price ~5,000 ₽). An alternative is a repair kit from Sonnax or ATP.

2. Wiring repair. If the problem is broken or oxidized contacts:

• 🔧 Clean the contacts on the solenoid and TCM connectors.
• 🔧 Check the circuit for short circuit (especially if there are traces of melting).
• 🔧 If necessary, replace the wiring harness (part number Nissan 25460-4M010).

3. Replacement of the TCM control unit. If all tests are successful, but the error remains, the control unit is to blame. On Murano The TCM is located under the center console. The original unit costs ~30,000 ₽, but you can find a used one with a guarantee.

4. Replacing the torque converter. In advanced cases (for example, if the oil is black with metal shavings), the torque converter will need to be replaced. On Murano with engine VQ35DE original fits Nissan 31300-4M000 (price ~60,000 ₽).

Common repair mistakes and how to avoid them

Many owners Murano they try to save money on repairs, but end up with even bigger problems. Here are the typical mistakes:

• 🚫 Error reset without repair. Easy code erase P1778 The scanner does not fix the problem - the error will return after 10–50 km.
• 🚫 Using non-original ATF oil. Cheap analogues destroy solenoids and automatic transmission clutches.
• 🚫 Replacing only the solenoid without flushing the valve body. Old dirt will clog the new solenoid in 1,000–2,000 km.
• 🚫 Ignoring TCM diagnostics. If the control unit is faulty, new parts will quickly fail.

To avoid these problems, follow these rules: "Automatic transmission repair is a system". Replacing one part without checking the associated components will lead to a relapse.

What happens if P1778 is not repaired?

If you ignore the error, after 5,000–10,000 km it will start chain of destruction:

1. Overheating of ATF oil → accelerated wear of clutches.

2. Wear of the torque converter clutch → metal shavings in the oil.

3. Clogging of valve body channels → failure of other solenoids.

4. Complete failure of the automatic transmission (repair from 150,000 ₽).

Prevention: How to prevent P1778 from coming back

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

1. Change ATF oil every 60,000 km. On Murano with mileage >100,000 km, it is better to reduce the interval to 40,000 km.
2. Use only original oil. For RE0F10A — Nissan Matic-S, for JF011E — Matic-J.
3. Avoid overheating the transmission. Do not tow heavy trailers or engage in drag racing.
4. Check the wiring. Once a year, inspect the solenoid and TCM connectors for oxidation.
5. Diagnose automatic transmission at the first symptoms. Jerks, slipping or delays when switching are a reason to check.

If you buy Murano with mileage, be sure to check the automatic transmission service history. Missing ATF oil change records is a red flag.

FAQ: Frequently asked questions about P1778 on Nissan Murano

Is it possible to drive with P1778?

For a short time (up to 500 km) - yes, but with caution. Long driving will lead to overheating of the automatic transmission and accelerated wear of the torque converter. The best thing to do is to immediately reduce the load on the transmission (avoid sudden acceleration and towing).

How much does it cost to repair a P1778?

The cost depends on the reason:

• 💰 Solenoid replacement: 5,000–10,000 ₽ (including labor).
• 💰 Wiring repair: 2,000–5,000 ₽.
• 💰 TCM replacement: 25,000–40,000 ₽.
• 💰 Replacement of torque converter: 50,000–80,000 ₽.

Can I reset P1778 myself?

Yes, but this is a temporary solution. To reset:

1. Disconnect the battery terminal for 10 minutes.
2. Or use a scanner (for example, Launch CReader) to clear errors.

If the code returns, repair is required.

What kind of oil to pour into the Murano automatic transmission when replacing?

Depends on the box model:

• 🔴 RE0F10A (until 2010) — Nissan Matic-S (article KE908-99932).
• 🔴 JF011E (after 2010) - Nissan Matic-J (article KE909-99932).

Volume for a complete replacement: 8–10 liters.

Where is the TCC solenoid located on a Murano?

The solenoid is included valve body, which is located inside the automatic transmission. To access you need:

1. Drain ATF oil.
2. Remove the box tray.
3. Disconnect the valve body connector (it is located to the right of the filter).

On Murano TCC solenoid is black cylinder with two contacts (usually second from the right in the row).