When your vehicle’s onboard diagnostics system detects an issue with the sensor reference voltage, it triggers the OBD-II code P0642. This code is categorized as having a moderate severity and indicates that the reference voltage circuit for one or more engine sensors is registering as low.
What Does the P0642 Code Mean?
The P0642 code specifically refers to a problem with the Sensor Reference Voltage “A” Circuit. The engine control module (PCM) sends out a 5-volt reference signal to various engine sensors. If the PCM detects an output signal that is incorrect or lower than expected, it sets this code.
What Causes the P0642 Code?
Several issues can lead to the setting of the P0642 code, including:
- Engine sensor failure
- Powertrain Control Module (PCM) failure
- Wiring issues, such as short circuits or breaks in the wiring harness
What Are the Symptoms of the P0642 Code?
The symptoms associated with the P0642 code can vary, but the most common include:
- Engine may not start
It’s important to note that the engine may not always fail to start, but this is a significant symptom to be aware of.
How Serious Is the P0642 Code?
The P0642 code is considered to have moderate severity. While it may not immediately threaten the vehicle’s safety or functionality, it is advisable to have it diagnosed and repaired within a reasonable timeframe to ensure optimal vehicle performance and to prevent further issues.
How to Diagnose the P0642 Code
Diagnosing the P0642 code typically involves the following steps:
- Use an OBD-II scanner to confirm the presence of the P0642 code and check for any additional codes.
- Inspect the wiring and connectors related to the sensor reference voltage circuit for any visible damage.
- Measure the voltage on the sensor reference circuit to determine if it is within the expected range.
- Test the engine sensors for proper operation and consult the vehicle’s service manual for specific testing procedures.
Common Repairs for the P0642 Code
Common repairs to address the P0642 code may include:
- Replacing faulty engine sensors
- Repairing or replacing damaged wiring or connectors
- Replacing the Powertrain Control Module (PCM) if it is determined to be faulty
How Much Does It Cost to Fix the P0642 Code?
The cost to fix the P0642 code can vary widely depending on the underlying cause. Simple repairs, such as wiring fixes, might range from $50 to $200, while replacing the PCM could cost $500 or more, depending on the vehicle make and model.
Can I Fix the P0642 Code Myself?
While some DIY enthusiasts may be able to diagnose and repair minor issues such as wiring problems, more complex issues like PCM failure typically require professional tools and expertise. If you are unsure, it is always best to consult with a certified shop to ensure proper diagnosis and repair.
