P0238 Turbocharger/boost sensor A circuit high

P0238 – OBD-II Trouble Code Technical Description

• Typical: Turbo/Boost Sensor "A" Circuit High Input
• GM: Dodge Chrysler Turbocharger Boost Sensor Circuit High Voltage:
• MAP sensor voltage too high

What does trouble code P0238 mean?

Code P0238 is a generic transmission diagnostic trouble code (DTC) that applies to vehicles with a turbocharger such as VW, Dodge, Mercedes, Isuzu, Chrysler, Jeep and others. The powertrain control module (PCM) uses the boost control solenoid to regulate the pressure generated by the turbocharger. The turbocharger boost pressure sensor provides pressure information to the PCM. When the pressure exceeds 4 V and there is no boost command, a code P0238 is logged.

The boost pressure sensor responds to changes in intake manifold pressure generated by the turbocharger and dependent on the accelerator and engine speed. The engine control module (ECM) uses this information to diagnose and protect the engine. The sensor has a 5V reference circuit, a ground circuit, and a signal circuit. The ECM supplies 5V to the sensor and grounds the ground circuit. The sensor sends a signal to the ECM, which monitors it for abnormal values.

The P0238 code is triggered when the ECM detects that the signal from the boost pressure sensor is abnormal, indicating an open circuit or high voltage.

P0229 is also a common OBD-II code that indicates a problem in the throttle/pedal position sensor circuit resulting in an intermittent input signal.

Symptoms of a P0238 trouble code may include:

If a P0238 code is present, the PCM will activate the check engine light and limit the boost pressure, which may result in a sluggish home condition. This mode is characterized by severe power loss and poor acceleration. It is important to correct the cause of this problem as soon as possible, as it can damage the catalytic converter.

Symptoms for code P0238:

1. The Check Engine light is on.
2. Limiting engine power during acceleration.
3. The Check Engine Light and Throttle Control (ETC) light are activated.
4. Various complaints are possible, depending on the manufacturer's settings.

Additional symptoms for throttle valve problems:

1. Complete throttle shutdown when stopping to prevent over-revving.
2. Fixing the throttle valve during acceleration to limit opening.
3. Restlessness or instability when braking due to a closed throttle.
4. Poor or no response during acceleration, limiting ability to accelerate.
5. Limit vehicle speed to 32 mph or lower.
6. Symptoms may go away once the vehicle is restarted, but the Check Engine light will remain on until repairs are made or the codes are cleared.

Possible reasons

Reasons for setting a P0299 code may include the following:

1. DTCs related to the Intake Air Temperature (IAT) sensor, Engine Coolant Temperature (ECT) sensor, or 5V reference.
2. Occasional wiring problems.
3. Faulty boost sensor “A”.
4. Short to voltage in the sensor circuit.
5. Faulty PCM (engine control module).
6. The boost pressure sensor harness is open or shorted.
7. Increase the electrical connection of the pressure sensor circuit.
8. The boost pressure sensor is faulty.
9. Faulty turbo/supercharger device.
10. The engine has overheated.
11. Misfire exceeds calibrated threshold.
12. The knock sensor (KS) is faulty.
13. Open circuit of the turbocharger pressure sensor with internal gain.
14. The turbocharger pressure connector A is damaged, causing the circuit to open.
15. Boost pressure sensor. The wiring harness is shorted between the sensor and the engine control module (ECM).

P0238 Brand specific information

1. 0238 – CHRYSLER MAP boost sensor voltage high.
2. P0238 – High voltage in the ISUZU turbocharger boost sensor circuit.
3. P0238 – High signal level in the turbocharger/boost sensor circuit “A” MERCEDES-BENZ.
4. P0238 – High signal level in the boost sensor circuit “A” VOLKSWAGEN Turbo/Super Charger.
5. P0238 – VOLVO boost pressure sensor signal too high.

How to diagnose code P0238?

Here is the rewritten text:

1. Scan codes and log freeze frame data to identify the problem.
2. Clears codes to see if the problem returns.
3. Checks the boost pressure sensor signal and compares it with the engine idle speed sensor signal to ensure that the readings match.
4. Inspect the turbocharger sensor wiring and connector for signs of a short in the wires.
5. Checks the turbocharger sensor connector for corroded contacts that could cause a short in the signal circuit.
6. Compares readings to specified specifications when analyzing sensor data.

What repairs can correct the P0238 trouble code?

Here is the rewritten text:

1. Repair or replace sensor wiring and connections as necessary.
2. Replace a faulty throttle control unit due to internal defects.
3. Replace or reprogram the ECM if recommended after performing selective testing and verifying that there are no other faults with the sensor or wiring.

What is P0238 Engine Code [Quick Guide]

Code P0229 is caused by erratic or intermittent signals from the sensor to the ECM. These signals are still within the specified range of the sensor when the signal is received by the ECM.