Causes of the P0642 diagnostic trouble code often vary depending on the precise circuit malfunctioning and how that circuit can malfunction. Most commonly, you’ll likely find a malfunctioning or faulty sensor, which means the sensor in question may need to be replaced. Bad or blown fuses or fusible links are very common as well. Sometimes, the problem involves the circuit, with problems like a damaged wire, a faulty wiring harness, or a poor connection. In very rare cases, an issue with the PCM or other faulty control modules can result in the P0642 code, but this is usually due to a PCM programming error, not an actual failure of the PCM.

You should avoid driving with OBD-II code P0642. As indicated, your problem could be extremely severe or not severe at all, and there’s no real way to determine which of these you’re experiencing until you check the code. If you continue driving with a very severe code, you could end up causing serious damage to your engine, which could be expensive and difficult to fix. When the check engine light turns on, even if you don’t notice any drivability problems, it’s a good idea to stop driving and get help with the code.

Inspection, as with diagnosis, is often difficult. Again, this generic code can be extremely difficult to untangle, as the code definition doesn’t give you much information. To inspect the code, you need to know the possibilities associated with this code, then which are most likely. You might need specialty equipment, a vehicle diagnostic scanner, and access to technical service bulletins. A knowledgeable mechanic can help you do the correct repair steps the first time.