What is an OBD2 code?

An OBD2 (On-Board Diagnostics) code is a diagnostic trouble code (DTC) generated by your vehicle's computer system when it detects a problem. These codes help identify specific issues with your vehicle's engine, transmission, emissions, or other systems.

How do I read OBD2 codes?

To read OBD2 codes, you'll need an OBD2 scanner. Plug it into your vehicle's OBD2 port (usually located under the dashboard), turn your key to the 'ON' position, and follow your scanner's instructions to retrieve the codes. Each code starts with a letter (P, B, C, or U) followed by four numbers.

What do the different types of OBD2 codes mean?

OBD2 codes are categorized by their first letter: P (Powertrain) for engine and transmission issues, B (Body) for interior systems like airbags, C (Chassis) for mechanical systems like brakes, and U (Network) for computer and module communication problems.

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Home » OBD2 Codes » P16E4

Code P16E4

Symptoms

• Check engine light on

• Possible engine performance issues

• Transmission shifting problems

Common Causes

• Faulty temperature sensor

• Wiring issues such as shorts or open circuits

• Faulty PCM/ECM/TCM

Glossary

PCM: Powertrain Control Module

ECM: Engine Control Module

TCM: Transmission Control Module

Related Codes

• P16E5

• P16E6

Laymans terms

This code means that the car's computer is having trouble reading the temperature from a sensor inside it. It's like when a thermometer doesn't work right and you can't tell how hot or cold it is.

Explanation

The P16E4 code indicates that the Powertrain Control Module (PCM), Engine Control Module (ECM), or Transmission Control Module (TCM) has detected a low voltage signal from the internal switch-on temperature sensor circuit.

Technical description

The PCM/ECM/TCM relies on an internal temperature sensor to monitor the temperature of the module itself. If the sensor circuit reports a voltage that is lower than expected, it triggers the P16E4 code. This could be due to a sensor malfunction, wiring issues, or a problem within the module.

Diagnosis steps

• Check for additional codes

• Inspect wiring and connectors for damage

• Test the temperature sensor

Repair procedures

• Repair or replace damaged wiring

• Replace faulty temperature sensor

• Replace PCM/ECM/TCM if necessary

Tools required

• OBD-II scanner

• Multimeter

• Basic hand tools

Estimated repair cost

$200 - $800

Difficulty level

Moderate

Commonly affected vehicles

• Chevrolet Malibu

• GMC Sierra

• Cadillac CTS

Preventive measures

• Regular maintenance checks

• Ensure proper connections and wiring

• Monitor engine performance

Error code type

Sensor Issue

User experience recommendations

• Do not ignore the check engine light

• Get a professional diagnosis if unsure

• Regularly maintain your vehicle

Warranty information

Check your vehicle's warranty for coverage on electronic components.

Historical data

This code has been associated with sensor and wiring issues in various vehicle models.

Urgency level

Moderate – Addressing this issue can prevent further engine or transmission problems.

Legal and safety notice

Driving with a malfunctioning temperature sensor can lead to engine or transmission damage.

Testing conditions

• Engine at operating temperature

• Vehicle stationary

Component location

The temperature sensor is located within the PCM/ECM/TCM module.

FAQs

Q: Can I drive with a P16E4 code?
A: It's not recommended as it can lead to further engine or transmission issues.

Q: How do I reset the check engine light after fixing the issue?
A: You can use an OBD-II scanner to clear the code after the repair.

Last updated: Jun 9, 2026 • Source: internal database

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