Error code P2138 on cars Nissan is one of the most common problems associated with the throttle control system. This malfunction can manifest itself in different ways: from unstable idle speed to a complete loss of power during acceleration. Most often the error occurs on models with an electronic throttle (ETCS — Electronic Throttle Control System), such as Qashqai J10/J11, X-Trail T31/T32, Teana J32 And Pathfinder R51/R52.

Unlike mechanical failures, P2138 indicates a signal discrepancy between the two throttle position sensors (TPS — Throttle Position Sensor). ECU (Electronic control unit) records an error when data from sensors TPS1 And TPS2 do not coincide by more than 10–15%. This can be caused by either a breakdown of the sensors themselves, or problems with wiring, connectors, or even mechanical wear of the damper.

In this article we will look in detail at:

  • 🔍 What does error P2138 mean? and how it manifests itself in practice
  • 🛠️ Step-by-step diagnostics using a scanner and multimeter
  • 💰 Repair cost in service vs. self-removal
  • ⚠️ Common mistakes during repairs, which may aggravate the problem

What does error code P2138 mean on Nissan?

Code P2138 stands for "Throttle/Pedal Position Sensor/Switch 'D'/E Circuit Range/Performance Problem". Translated into Russian, this means that the ECU has detected a signal mismatch between two throttle position sensors. In the system ETCS two sensors are used (TPS1 And TPS2), which duplicate each other to increase reliability. If their readings diverge, the control unit switches the engine to emergency mode (limp mode).

Feature of the error P2138 the fact that it can appear either constantly or occasionally - for example, when you sharply press the gas pedal or after warming up the engine. On some models Nissan (For example, Juke F15 or Note E12) the error is often accompanied by other codes such as P0120 (throttle position sensor circuit malfunction) or P2101 (throttle drive error).

Symptoms that may indicate P2138:

  • 🚗 Floating speed at idle (from 500 to 1500 rpm)
  • 🐢 Slow response on the gas pedal (delay 1–2 seconds)
  • ⚡ Jerks during acceleration, especially in low gears
  • 🔴 Check Engine Light Illuminates (sometimes flashes)
  • 🚫 Engine start failure (in rare cases)

⚠️ Attention: If the error P2138 accompanied by code P2106 (throttle ECU processor error), this may indicate a malfunction of the control unit itself. In this case, the ECU needs to be reflashed or replaced, which will cost 15–30 thousand rubles.

Causes of error P2138

Error P2138 does not have a single cause - it can be caused by both mechanical failures and electronic failures. Below is a list of the most common causes, ranked by frequency of occurrence:

Reason Frequency (%) Cost of elimination (₽)
Worn or dirty throttle valve 40% 1,500–3,000 (cleaning)
Malfunction of TPS1 or TPS2 sensors 30% 2,500–6,000 (sensor replacement)
Damage to wiring or connectors 15% 500–2,000 (harness repair)
Throttle actuator malfunction 10% 8,000–15,000 (assembly replacement)
Throttle ECU firmware failure 5% 3,000–10,000 (reflash)

By car Nissan with a mileage of more than 100 thousand km, most often the problem lies in damper contaminated. Carbon deposits and oil deposits interfere with the smooth operation, causing the sensors to produce incorrect signals. On newer models (eg. Qashqai J11 or Ariya) the malfunction is most often associated with electronics — oxidation of contacts or failure of sensors.

Deserves special attention weight problem. On many Nissan The negative wire of the throttle sensors is attached to the body next to the battery. Over time, this area oxidizes, resulting in unstable readings. TPS. You can check this by measuring the resistance between the sensor ground and the body - it should be close to 0 ohm.

📊 Which Nissan model are you experiencing error code P2138 with?
  • Qashqai
  • X-Trail
  • Teana
  • Juke
  • Pathfinder
  • Other model

Diagnosing error P2138: step-by-step instructions

For accurate diagnosis P2138 you will need a scanner (for example, Launch X431 or ELM327) and a multimeter. If you don’t have a scanner, you can do a visual inspection and check the voltages, but this will take more time.

Step 1: Reading Errors

Connect the scanner to the diagnostic connector OBD-II (usually located under the steering wheel). Besides P2138, pay attention to the accompanying codes:

  • 🔹 P0122/P0123 — low/high sensor signal TPS1
  • 🔹 P0222/P0223 — low/high sensor signal TPS2
  • 🔹 P2100/P2101 — malfunction of the throttle drive

If there are codes P0100 or P0102, the problem may be related to the mass air flow sensor (Mass air flow sensor), which indirectly affects the operation of the throttle.

Step 2: Check the throttle body

Remove the air pipe and inspect the damper. If there is carbon or oil deposits on the walls, they must be cleaned using carb cleaner (For example, Liqui Moly Pro-Line Drosselklappen-Reiniger). Do not use metal brushes - they will damage the coating.

Step 3: Check TPS Sensors

Disconnect the throttle assembly connector and measure the resistance between the sensor contacts (see diagram for your model). For Nissan Qashqai J10 normal values:

  • 🔹Between 1 and 2 contacts TPS1: 1–5 kOhm (depending on damper position)
  • 🔹Between 3 and 4 contacts TPS2: similar

If the resistance is 0 or ∞, the sensor is faulty.

Step 4: Check the Wiring

Check the wires from the throttle connector to the ECU for breaks or short circuits. Pay attention to the condition of the insulation - often the wires rub against the intake manifold.

1. Read all errors by the scanner

2. Inspect the throttle valve for carbon deposits

3. Check the resistance of sensors TPS1 and TPS2

4. Measure the voltage at the connector (there should be 5V on the power supply)

5. Check the wiring for breaks -->

How to fix error P2138: from cleaning to replacement

The repair method depends on the cause of the problem. Below is an algorithm of actions from the simplest (cleaning) to the most complex (replacing the ECU).

1. Cleaning the throttle body

If the valve is dirty, it can be cleaned without removing it:

  • 🔧 Remove the air pipe
  • 🧴 Apply cleaner to the walls of the damper and the plate itself
  • 🧹 Remove carbon deposits with a soft cloth or brush
  • 🔄 Repeat the procedure 2-3 times
Important: Do not press the damper with your hands - this may damage the actuator.

2. Replacing TPS sensors

If the sensors are faulty, they must be replaced. On most models Nissan sensors TPS1 And TPS2 come assembled with the throttle assembly, but on some (for example, X-Trail T31) they can be replaced separately. The average cost of a sensor is 2,500–4,000 rubles.

3. Wiring repair

If the problem is broken or oxidized contacts, restore the circuit:

  • 🔌 Clean the oxidized contacts in the connector
  • 🔧 Replace damaged wires (use heat shrink tubing)
  • 🛠️ Check the ground - add additional wire if necessary

4. Throttle adaptation

After cleaning or replacing sensors, it is necessary to throttle training. To do this:

  1. Turn on the ignition for 3 seconds (without starting the engine).
  2. Turn off the ignition for 10 seconds.
  3. Repeat the cycle 3 times.
  4. Start the engine and let it idle for 5 minutes.

If adaptation fails, a diagnostic scanner (for example, Consult-III+).

⚠️ Attention: On some models Nissan (For example, Pathfinder R52) after replacing the throttle assembly, ECU firmware is required. Without this, the engine will operate in emergency mode.
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If after cleaning the damper an error P2138 remains, try resetting the ECU by disconnecting the battery for 15 minutes. This sometimes helps with “stuck” values ​​in block memory.

Common mistakes when repairing P2138

Many owners Nissan are faced with the fact that after self-repair there is an error P2138 returns or new problems appear. Here are the most common mistakes:

1. Using aggressive cleaners

Some car owners clean the throttle valve WD-40 or solvent 646. These products destroy the protective coating of the damper, which leads to accelerated carbon formation. Use only specialized cleaners, e.g. CRC Throttle Body Cleaner.

2. Incorrect throttle adaptation

After cleaning or replacing sensors, many people forget to damper training. Without this, the ECU continues to use old calibration data, which leads to unstable engine operation. On some models (for example, Nissan Juke) adaptation is only possible through diagnostic equipment.

3. Ignoring weight check

Poor ground contact is one of the most invisible but common causes P2138. Many people check sensors and wiring, but forget to measure the resistance between the throttle body and the body. If it is more 0.5 ohm, it is necessary to clean the mounting location or lay an additional ground wire.

4. Replacement of only one sensor

If one of the sensors fails (TPS1 or TPS2), both need to be replaced. Even if the second sensor is working, its characteristics may have changed over time, which will again lead to signal discrepancies.

5. Neglecting to check the ECU

In rare cases, an error P2138 caused by a malfunction of the throttle control unit itself. If the problem persists after replacing the sensors and cleaning the damper, check the ECU for corrosion or damage to the circuit board. On models Nissan before the 2010 release, this is more common due to poor-quality electronics protection.

What happens if you ignore P2138?

If the error is not resolved P2138, over time this can lead to:

  • 🔥 Catalyst overheating due to suboptimal fuel mixture
  • 🛑 Complete engine stop while driving (if the ECU switches the system to emergency mode)
  • 💸 Increased fuel consumption by 10–20%
  • 🔧 Transmission wear due to jerking when changing gears

On some models (for example, Nissan Murano Z51) long drive with P2138 may cause turbo malfunction due to incorrect boost pressure.

Cost of repairs in service vs. self-removal

Error repair cost P2138 depends on the reason and car model. Below is a cost comparison table:

Type of repair Cost in service (₽) Cost yourself (₽) Difficulty (1–5)
Cleaning the throttle valve 2 000–3 500 300–800 (cleaner + brush) 1
Replacing TPS Sensors 4 000–7 000 2,500–4,000 (sensors) 3
Wiring repair 1 500–3 000 200–500 (wires + heat pipe) 2
Replacing the throttle assembly 12 000–20 000 8,000–15,000 (knot) 4
Flashing the ECU 5 000–12 000 — 5

DIY repairs are beneficial if you have experience with electronics and diagnostic equipment. However, on some models (for example, Nissan GT-R or Ariya) the throttle valve is integrated with the engine management system, and its replacement requires special adaptation software.

Average diagnostic cost P2138 in service - 1,000–1,500 rubles. If you are not sure of the cause of the malfunction, it is better to start there to avoid unnecessary expenses on replacing working parts.

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On models Nissan with the system ETCS-i (For example, Teana J32) the throttle valve has no mechanical connection with the gas pedal. There's an error here P2138 is more often associated with electronic components rather than mechanical wear.

Preventing error P2138

To avoid reappearance P2138, follow these guidelines:

  • 🔧 Clean the throttle valve every 50–60 thousand km (or once every 2 years)
  • ⚡ Check the on-board voltage — surges can damage sensors
  • 🛢️ Use quality fuel - bad gasoline accelerates the formation of soot
  • 🔌 Process contacts connectors with special lubricant (for example, Liqui Moly Electronic-Spray)
  • 📊 Watch out for bugs - if P2138 appears sporadically, record conditions (cold/hot engine, load, etc.)

For cars with mileage of more than 150 thousand km, it is recommended replace the throttle assembly, even if cleaning temporarily fixes the problem. The life of the plastic drive gears is limited, and over time they begin to slip, which again leads to an error P2138.

Also note driving style. Sudden pressure on the gas pedal and frequent short trips (when the engine is not fully warmed up) accelerate wear on the throttle body. Try to maintain speed in the range of 2-3 thousand rpm when driving - this is the optimal mode for the longevity of the system.

FAQ: Frequently asked questions about error P2138

Is it possible to drive with error code P2138?

Short term - yes, but not recommended. The engine will operate in limp mode with limited power. Long ride with P2138 may lead to:

  • 🔥 Overheating of the catalyst
  • 🛑 Unpredictable jerks when overtaking
  • 💸 Increased fuel consumption

If the error appears for the first time, you can go to the service center, but it is better to eliminate the cause as soon as possible.

Why does P2138 appear after washing the engine?

Water or detergent may have gotten into the throttle valve connector or sensor contacts. This leads to:

  • 💧 Short circuit
  • 🔌 Contact oxidation
  • 📉 Unstable signals with TPS

Solution: dry the connector with a hairdryer (cold air) and treat the contacts WD-40 Contact Cleaner.

How to reset error P2138 without a scanner?

You can reset the error by disconnecting the battery for 10–15 minutes. However, this will not eliminate the cause! If the problem persists, the error will return after a few kilometers. To completely reset throttle adaptations on some models Nissan required:

  1. Disconnect the battery terminal for 30 minutes
  2. Press the brake pedal all the way and hold for 1 minute (discharges the ECU capacitors)
  3. Connect the battery and start the engine without touching the gas pedal
Could P2138 be caused by a faulty accelerator pedal?

Yes, but extremely rarely. Error P2138 Connected to the throttle sensors, not the pedal. However, on models with the system Drive-by-Wire (For example, Nissan Leaf) a malfunction of the gas pedal can indirectly affect the operation of the throttle. If you suspect a pedal, check:

  • 🔌 Integrity of wiring from pedal to ECU
  • 📊 Pedal sensor readings (should change smoothly when pressed)
What spare parts are best to choose for replacement?

For models Nissan We recommend original spare parts or analogues of proven brands:

Detail Original (item) Analogue (brand)
Throttle assembly 22680-4M000 (Qashqai J10) Ajusa, Febi, Blue Print
TPS sensor 22680-4M00A Hella, Bosch, VDO
Throttle wiring Included in harness 25520-4M000 Repkit, ACDelco

Beware of cheap Chinese analogues - they often fail after 10-20 thousand km.