Error code P1807 on Nissan Pathfinder: decoding, diagnosis and repair

Error P1807 on Nissan Pathfinder - one of those problems that can baffle even experienced car owners. This code is associated with malfunctions in the transmission control system, but its manifestations can vary from barely noticeable jerks when changing gears to a complete refusal of the transmission to change gears. Unlike more common errors like P0300 (misfire) or P0171 (lean mixture) P1807 requires an integrated approach - it is important to understand whether the problem is software, mechanical or electrical.

In this article we will look in detail at what is hidden behind the code. P1807 on Pathfinder (including models R51 And R52), what symptoms should alert you, and - most importantly - how to independently diagnose and fix the problem. We won't limit ourselves to boilerplate advice like "check the wires": instead, you'll get specific action algorithms based on the experience of service technicians and analysis of typical breakdowns of a given model. If you encounter this error, read on to save time and money on repairs.

What does error code P1807 mean on Nissan Pathfinder?

Code P1807 in the diagnostic system Nissan stands for "Torque Converter Lockup Solenoid Circuit Malfunction" (Torque Converter Clutch Solenoid Circuit Malfunction). This solenoid is responsible for locking up the torque converter (TCT) in an automatic transmission, which reduces slippage and improves economy at high speeds. When the transmission control unit (TCM) detects an incorrect signal from the solenoid or its circuit, it activates an error P1807.

On Pathfinder with boxes RE5R05A (installed on models before 2010) and RE7R01A (after 2010) this code is often accompanied by the following symptoms:

• 🔴 Jerks or impacts when changing gears, especially at 3-4 speeds.
• 🔴 Increased engine speed without increasing speed (the transmission “slips”).
• 🔴The indicator lights up Check Engine or SLIP on the dashboard.
• 🔴 The box goes into “emergency mode” (one gear is fixed, usually 3rd).

It is important to understand that P1807 - this is not a verdict on the box, but a signal about the need for diagnostics. In 60% of cases, the problem is solved by replacing the solenoid or cleaning the contacts, but ignoring the error can lead to wear of the clutches and expensive automatic transmission repairs.

The main causes of error P1807

Causes P1807 on Nissan Pathfinder can be divided into three categories: electrical, mechanical and software. Let's look at each of them in detail.

1. Electrical faults:

• 🔌 Damage to the wiring or oxidation of the contacts of the gas turbine engine blocking solenoid.
• 🔌 Short circuit or open circuit in the solenoid control circuit.
• 🔌 Malfunction of the transmission control unit (TCM).

2. Mechanical problems:

• ⚙️ Worn or seized torque converter lock-up solenoid.
• ⚙️ Contamination of the oil in the automatic transmission (leads to jamming of the solenoid).
• ⚙️ Damage to the torque converter (wear of friction discs).

3. Software glitches:

• 💻 Incorrect firmware TCM (relevant after flashing or updating the software).
• 💻 Failure of sensors (for example, speed sensor or throttle position).

According to statistics from service centers, most often P1807 on Pathfinder called oxidation of the solenoid contacts or wear of its winding. Less often, the problem lies in the mechanics of the torque converter. To accurately determine the cause, diagnostics with real-time reading of parameters will be required.

How are errors P1807 and P0740 related?

Error P0740 ("Torque Converter Lockup Circuit Malfunction") often appears along with P1807, since both codes refer to the same system. However P0740 indicates a problem in the mechanical part (for example, wear of the clutches of the gas turbine engine), while P1807 - a malfunction in the solenoid control circuit. If both errors are present at the same time, most likely you will need to repair the torque converter or change the oil in the automatic transmission and flush the solenoids.

Diagnosing error P1807: step-by-step instructions

Before starting repairs, it is necessary to accurately determine the cause of the error. Below are step-by-step instructions for diagnosis P1807 on Nissan Pathfinder.

Step 1: Reading Error Codes

Use a scanner (eg Launch CReader or ELM327) to read all saved codes. Please note related errors such as P0730 (incorrect gear ratio) or P0740. If except P1807 There are no other codes, the problem is most likely in the solenoid or its circuit.

Step 2: Check wiring and contacts

• 🔧 Disconnect the solenoid block connector (located on the automatic transmission housing).
• 🔧 Inspect the contacts for oxidation or damage.
• 🔧 Test the circuit with a multimeter: the resistance between the contacts of the gas turbine engine blocking solenoid should be within the limits 10–20 Ohm.

Step 3. Checking the engine blocking solenoid

If the wiring is OK, remove the solenoid and check its functionality. To do this:

1. Connect the solenoid to the power source 12 V (you can use a battery).
2. Listen to see if it makes a clicking sound when voltage is applied. No click indicates a malfunction.

Step 4. Diagnosis of the torque converter

If the solenoid is OK, but the error remains, check the torque converter:

• 🔧 Inspect the oil in the automatic transmission: the presence of metal shavings or a burning smell indicates wear of the clutches.
• 🔧 Check the pressure in the hydraulic system of the box (pressure gauge and adapter required).

Read all errors with a scanner|Check the contacts of the gas turbine engine blocking solenoid|Ring the circuit with a multimeter|Test the solenoid for functionality|Inspect the oil in the automatic transmission for the presence of foreign particles

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How to fix error P1807: from simple to complex

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

1. Cleaning contacts and replacing wiring

If the problem is oxidized contacts or damaged wiring:

• 🛠️ Clean the solenoid and connector contacts TCM special liquid (for example, CRC Contact Cleaner).
• 🛠️ Replace damaged wires using heat shrink tubing for insulation.

2. Replacing the gas turbine engine blocking solenoid

If the solenoid is faulty, it must be replaced. For Nissan Pathfinder Suitable original parts with article numbers:

Box model	Solenoid part number	Approximate price, rub.
RE5R05A (until 2010)	31397-31X00	4 500 – 6 000
RE7R01A (after 2010)	31397-1XF00	5 000 – 7 500
Universal analogue	Sonnax 77944-08K	3 200 – 4 800

3. Changing the automatic transmission oil and flushing the solenoids

If the oil is contaminated, perform a complete change with flushing:

• 🔧 Drain the old oil (volume ~8–10 liters for a complete replacement).
• 🔧 Rinse the tray and magnets from metal shavings.
• 🔧 Fill with new oil (recommended Nissan Matic-S or Idemitsu ATF Type-J).

4. Repair or replacement of the torque converter

If the problem is in the mechanical part of the gas turbine engine, it will need to be repaired or replaced. Average cost of a new torque converter for Pathfinder — 30,000 – 50,000 rub.. In some cases, replacing friction discs helps (work price ~15,000 rub.).

Common repair mistakes and how to avoid them

Many car owners make typical mistakes that lead to the recurrence of P1807. Here's what not to do:

❌ Ignoring related errors

If together with P1807 other codes are present (for example, P0730 or P0740), all problems need to be eliminated comprehensively. Replacing one solenoid will not help if the torque converter is worn out.

❌ Saving on oil for automatic transmission

Using cheap analogues instead of the original Nissan Matic-S leads to rapid wear of solenoids and clutches. Oil must meet specification JWS 3309.

❌ Incorrect solenoid installation

When replacing the engine blocking solenoid, it is important:

• 🔧 Make sure the O-ring is intact and installed correctly.
• 🔧 Do not overtighten the fastening bolts (tightening torque - 10–12 Nm).

❌ Neglect of TCM diagnostics

If the error remains after replacing the solenoid and oil, the problem may be in the transmission control unit (TCM). In this case, it will need to be re-flashed or replaced. Cost of a new one TCM for Pathfinder - from 25,000 rub., but firmware often helps (price ~5,000 rub.).

⚠️ Attention: When replacing TCM it is necessary to “bind” the new unit to the car through diagnostic equipment. Without this, the box will not work correctly.

Cost of repairs in service vs. do-it-yourself repair

Elimination prices P1807 in services vary depending on the cause and region. Below is the approximate price:

Type of work	Cost of service, rub.	Cost on your own, rub.
Diagnostics (scanner + circuit check)	1 500 – 3 000	0 (if scanner is available)
Replacing the gas turbine blocking solenoid	8 000 – 12 000	3,000 – 5,000 (cost of part)
Complete automatic transmission oil change	5 000 – 8 000	3,000 – 4,500 (oil + filter)
Torque converter repair	20 000 – 35 000	15,000 – 25,000 (spare parts + tools)
Replacing TCM with firmware	30 000 – 50 000	25,000 – 35,000 (part + firmware)

Self-repair is cheaper, but requires skills in working with diagnostic equipment and knowledge of the automatic transmission. If you are not confident in your abilities, it is better to contact a service center - mistakes when repairing the transmission can result in even greater expenses.

⚠️ Attention: When changing the oil in an automatic transmission Nissan Pathfinder It is strictly forbidden to use flushing liquids! They can damage clutches and solenoids. Use only original oil and the partial replacement method (3-4 cycles).

Preventing error P1807 on Nissan Pathfinder

To avoid reappearance P1807, follow these guidelines:

1. Regularly change the automatic transmission oil

• 🔧 Change the oil every 60,000 km (or once every 4 years), even if the mileage is small.
• 🔧 Use only original oil Nissan Matic-S or its certified analogues.

2. Monitoring the condition of the torque converter

• 🔧 If vibrations or jerks appear during acceleration, immediately check the oil level and condition.
• 🔧 Avoid long towing or driving with a trailer - this increases the load on the gas turbine engine.

3. Electronics diagnostics

• 🔧 Clean the connector contacts periodically TCM and solenoids.
• 🔧 Check circuits for short circuits, especially after washing the engine.

4. Correct operation of the box

• 🔧 Avoid sharp starts and braking - this reduces the resource of the clutches.
• 🔧 In winter, warm up the box before driving (2-3 minutes at idle is enough).

FAQ: Frequently asked questions about error P1807

Is it possible to drive with error code P1807?

Short term - yes, but not recommended. The box may go into emergency mode, which will increase wear on parts. If you ignore the error, this will lead to expensive repairs to the torque converter or the entire automatic transmission.

How to reset error P1807 after repair?

Use a diagnostic scanner (eg Launch X431 or Autel) to reset codes. Simply removing the battery terminal is not enough - a full reboot is required. TCM.

Can P1807 be caused by bad gasoline?

No, P1807 not directly related to fuel. However, low-quality gasoline can cause detonation, which indirectly affects the operation of the transmission. But the main reasons are the electrics or mechanics of the automatic transmission.

How much does it cost to replace a torque converter on a Pathfinder?

The cost of a new torque converter is from 30,000 to 50,000 rub., replacement work - 10,000 – 15,000 rub.. In some cases, it is cheaper to repair an old gas turbine engine (repair price - 15,000 – 25,000 rub.).

Is it possible to replace the gas turbine engine blocking solenoid yourself?

Yes, if you have experience with automatic transmissions. You will need to remove the transmission pan, drain the oil and carefully remove the faulty solenoid. The main thing is not to damage the O-ring and connect the connector correctly.