Error P2138 on Nissan Qashqai: a complete analysis of causes and solutions

Fault code P2138 on Nissan Qashqai (especially relevant for models with gasoline engines MR20DD, HR16DE and diesel K9K) is one of the most common problems with the electronic throttle control system. This error indicates a mismatch between the signals from the accelerator pedal position sensors (APP Sensor 1/2) and throttle position sensors (TP Sensor 1/2). As a result, the ECU (ECU) puts the engine into emergency mode, limiting power and causing jerks during acceleration.

Owners Kashkaya They often encounter this problem after 100–150 thousand kilometers, but the error may appear earlier - for example, due to low-quality fuel, moisture getting into the connectors, or ECU firmware failures. In this article we will look in detail at:

• 🔍 What exactly does P2138 mean? and how it manifests itself in practice.
• 🛠️ Step-by-step diagnostics - from simple checks to deep scanning.
• 💰 Repair cost in the service vs self-removal.
• ⚠️ Common mistakes during repairs, which only aggravate the problem.

What does error P2138 mean on Nissan Qashqai

Code P2138 stands for "Throttle/Pedal Position Sensor/Switch 'D'/E Voltage Correlation". Translated into practice, this means that the ECU has detected a discrepancy between the signals of two independent throttle position sensors (TP Sensor 1 And TP Sensor 2) or between the gas pedal and throttle sensors. The system interprets this as critical malfunction threatening safety, and activates emergency mode (Limp Mode).

On Nissan Qashqai (especially J10/J11) the error is often accompanied by the following symptoms:

• ⚡ Sudden power drops when you press the gas (the engine stalls).
• 🚗 Jerks and twitches at idle or during acceleration.
• 🔥 Check Engine light comes on (sometimes flashes).
• 🛑 RPM limit up to 2–3 thousand RPM.

It is important to understand that P2138 is not an independent fault, but a consequence of another problem. It can be caused by:

• 🔧 Mechanical wear of the throttle assembly.
• 💧 Moisture or oil getting into the sensor connectors.
• 🔌 Short circuit or broken wiring.
• 🖥️ ECU firmware failure (relevant after chip tuning).

Causes of P2138: from simple to complex

To effectively eliminate an error, you need to systematically check all possible causes. Let's start with the most likely and easiest to diagnose:

Reason	Probability (%)	Difficulty in eliminating
Throttle valve contamination	40%	⭐ (cleaning in 30 minutes)
Malfunction of the damper position sensor (TP Sensor)	25%	⭐⭐ (sensor replacement)
Damage to wiring or connectors	20%	⭐⭐⭐ (testing with a multimeter)
ECU firmware failure	10%	⭐⭐⭐⭐ (flashing)
Mechanical wear of the damper	5%	⭐⭐⭐⭐⭐ (replacement of unit)

The most common reason is throttle body contamination. On Qashqai With a mileage of over 80 thousand km, carbon deposits form on the damper, which interferes with its smooth operation. The sensors detect an incorrect position, and the ECU issues P2138. Solution - cleaning the throttle body with a special cleaner (For example, LIQUI MOLY Pro-Line Drosselklappen-Reiniger).

If cleaning does not help, the next most common reason is malfunction of TP Sensor 1/2 sensors. They are located directly on the throttle assembly and fail over time. Checked with a multimeter: the resistance between the contacts should be within 1–5 kOhm (see the manual for your model for exact values).

⚠️ Attention: On Nissan Qashqai J11 (2014–2021) TP Sensor sensors are non-separable - if a breakdown occurs, the entire throttle assembly is replaced. On J10 (2007–2013) sensors can be replaced separately.

Diagnosing error P2138: step-by-step instructions

For an accurate diagnosis you will need:

• 🔧 OBD-II scanner (For example, ELM327 or Launch CReader).
• 🔍 Multimeter (to check sensors and wiring).
• 🧴 Throttle Body Cleaner.
• 📝 Repair manual for your model Qashqai (can be found at Nissan-Technical.info).

Diagnostic algorithm:

Read errors with scanner and write down all codes

Inspect the throttle assembly for dirt and mechanical damage

Ring the wiring of the TP Sensor 1/2 sensors (pins 1–6 on the connector)

Check the voltage on the sensors (should be 5V on pin 1)

Reset errors and test the car -->

Start with reading all errors. In addition to P2138, related codes are often found:

• 🔴 P0120 — Malfunction of the throttle position sensor circuit.
• 🔴 P0222 — low signal from the damper position sensor.
• 🔴 P0606 — ECU malfunction (requires flashing).

If there are several errors, first eliminate those related to TP Sensor or APP Sensor. For example, the combination P2138 + P0120 almost guaranteed to indicate a problem throttle sensor.

Next visually inspect the throttle assembly. On Qashqai it is located to the right of the intake manifold (when viewed in the direction of travel). Please note:

• 🩹 Traces of oil or coolant - indicate a leak from under the gasket.
• ⚡ Oxidation of contacts on the sensor connector.
• 🔄 Damper play - if it is loose, the unit will need to be replaced.

How to resolve error P2138: from cleaning to replacing the unit

Depending on the cause, repair methods range from simple cleaning to replacing the throttle body or reflashing the ECU. Let's consider each option in detail.

1. Cleaning the throttle body

The simplest and cheapest method that helps in 40% of cases. You will need:

• 🧴 Throttle cleaner (LIQUI MOLY, Wynn's or equivalent).
• 🧻 Lint-free rag or paper towels.
• 🔧 Screwdriver (for dismantling the air duct pipe).

Step by step instructions:

1. Remove the air duct pipe by disconnecting the clamps.
2. Apply cleaner to the damper and wipe it thoroughly on both sides.
3. Treat the air supply channel (especially if there is oil deposits).
4. Wait 10 minutes for the solvent to evaporate and put everything back together.
5. Clear the errors with the scanner and start the engine. Let it idle for 5-10 minutes.

⚠️ Attention: After cleaning, the speed may temporarily float - this is normal. The ECU needs time (10–20 km) to re-adapt to the clean throttle. If the error persists, proceed to the next step.

2. Checking and replacing TP Sensors

If cleaning does not help, check the throttle position sensors. On Nissan Qashqai there are two of them: TP Sensor 1 (main) and TP Sensor 2 (backup). To check:

1. Disconnect the connector from the throttle assembly.
2. Test the circuits with a multimeter:
   • Between contacts 1–2 (food) must be 5V.
   • Between 3–4 (signal) - resistance 1–5 kOhm (depending on the position of the damper).

If the values are outside the limits, the sensor is faulty and requires replacement.

On Qashqai J10 sensors can be purchased separately (item: 22680-4M000 for HR16DE, 22680-JK00A for MR20DD). On J11 you will have to change the entire assembly (article: 22690-4M01A).

3. Checking wiring and connectors

An open or short circuit in the sensor circuit is the third most common cause of P2138. Inspect:

• 🔌 Connector on the throttle body — whether there is oxidation or bent contacts.
• 🔗 Wiring from the ECU to the sensors (especially in places of inflection near the collector).
• 🛡️ Fuse F30 (10A) in the block under the hood - it is responsible for powering the sensors.

To test, use a multimeter in mode 200 Ω. Resistance between ECU connector contacts (pins 24–25 for TP Sensor 1) should be 0 Ω (no break).

How to find TP Sensor pins on the ECU connector?

On Nissan Qashqai J10/J11 The ECU connector is located under the plastic cover near the battery. Pinout:

- TP Sensor 1: pin 24 (signal), pin 25 (ground), pin 12 (power + 5V).

- TP Sensor 2: pin 26 (signal), pin 27 (ground).

The diagram may differ depending on the year of manufacture - check the manual.

Resetting throttle adaptations after repair

After any intervention in the throttle assembly (cleaning, replacing sensors or the entire assembly), it is necessary reset ECU adaptations. Otherwise, the P2138 code may return even if the mechanical part is normal.

There are two reset methods:

1. Automatic reset (for most cases):
   • Clear errors with a scanner.
   • Start the engine and let it idle for 5-10 minutes.
   • Turn off the ignition for 30 seconds.
   • Repeat the start - the ECU will adapt itself.
2. Forced adaptation (if automatic reset didn't help):
   • Connect a scanner with support Nissan Consult (For example, Launch X431).
   • Select menu Special Functions → Throttle Valve Learning.
   • Follow the instructions on the screen (usually you need to press the gas pedal all the way down and release).

On Qashqai J11 with engine MR20DD adaptation may require additional steps:

1. Выключить зажигание на 10 секунд.
2. Включить зажигание (не заводить двигатель).
3. Полностью нажать и отпустить педаль газа 5 раз подряд.
4. Подождать 7 секунд, затем завести двигатель.

⚠️ Attention: If, after resetting the adaptations, error P2138 appears again within 10–20 km, the problem is not resolved. The throttle assembly itself or the ECU is probably faulty.

When is throttle body replacement required?

Replacing the throttle assembly with Nissan Qashqai - an extreme measure, but sometimes you can’t do without it. Signs that the unit needs to be changed:

• 🔧 Mechanical play of the damper (it dangles even with a light touch).
• 🔥 Traces of plastic melting inside the node.
• 📉 Power drop even after cleaning and replacing sensors.
• 🔄 Permanent return of P2138 after reset.

Cost of a new node:

Model Qashqai	Article	Price (original), ₽	Price (analog), ₽
J10 (2007–2013), HR16DE	22690-JK00A	12 000–15 000	6 000–8 000
J10 (2007–2013), MR20DD	22690-4M000	14 000–17 000	7 000–9 000
J11 (2014–2021), HR16DE	22690-JK01A	15 000–18 000	8 000–10 000
J11 (2014–2021), MR20DD	22690-4M01A	16 000–20 000	9 000–12 000

When replacing a unit, be sure to:

• 🔧 Use new gasket (comes with the unit).
• 🧴Apply sealant at the junction with the collector (for example, Loctite 574).
• 🔌 Connect the connector only after the node is completely installed.

FAQ: Frequently asked questions about error P2138

Is it possible to drive with error code P2138?

Technically possible, but not advisable. The ECU will put the engine into emergency mode (Limp Mode), which will limit power to 2–3 thousand rpm. Long-term driving in this mode can lead to:

• 🔥 Overheating of the catalyst (due to incorrect fuel mixture).
• 🛢️ Increased fuel consumption (up to 15–20%).
• 🔧 Accelerated wear of the gearbox (due to jerking).

We recommend that the error be resolved within 1–2 weeks.

Will resetting the ECU (removing the battery terminal) help?

A short reset (10-15 minutes) can clear the error, but only if it was caused by a temporary glitch. If the cause is mechanical (dirt, faulty sensor), P2138 will return after 10–50 km. Reset is only useful after repair to adapt the throttle.

Is it possible to clean the throttle without removing it?

It is possible, but the efficiency will be lower. Without dismantling you will not be able to:

• 🧹 Clean the back of the damper (where most of the soot accumulates).
• 🔍 Check the condition of sensors and wiring.
• 🛠️ Lubricate the damper axle (if it jams).

For complete cleaning, it is better to remove the unit (it will take 20–30 minutes).

What oil should I use to lubricate the throttle shaft?

Never use regular motor oil or WD-40! They attract dirt. Optimal options:

• 🧴 LIQUI MOLY Drosselklappen-Fett (special lubricant for chokes).
• 🧴 CRC Throttle Body Cleaner (lubricant included in the cleaner).
• 🧴 Silicone Grease (silicone grease, not aggressive to plastic).

Apply a minimal amount - excess lubricant may enter the manifold.

What should I do if the error remains after replacing the throttle?

If P2138 does not go away after replacing the unit, check:

1. Correct connection of connectors (mixed-up contacts are a common mistake).
2. Wiring condition from the ECU to the throttle (possibly damaged during replacement).
3. ECU firmware - sometimes an update is required (especially on Qashqai J11 after 2017).
4. Gas pedal sensors (APP Sensor) - they can also give a false signal.

If everything is in order, but the error remains, the problem may be in the ECU itself. In this case, only diagnostics in the equipment service will help. Nissan Consult.