Reference meaning
What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Narrow by vehicle
A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Scan worksheet →Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0642Sensor Reference Voltage 1 Circuit Low
Manufacturer communications
11Original wording in English
BENTLEY
Service Info: Engine Control Module (ECM) 5V Reference Circuits. Customer statement / workshop findings: This TPI provides supplementary technical information to support diagnosis of ECM 5V reference circuit DTCs. It details the sensors associated with each reference circuit (A, B, and C) and outlines relevant guidance to assist…
KIA
TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: EGR VALVE ASSEMBLY REPLACEMENT (SC320) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information to replace the Exhaust Gas Recircul…
HYUNDAI
The exhaust gas recirculation (EGR) valve assembly in certain vehicles (listed below) may contain a sensor that was contaminated with solder flux during manufacturing, which could potentially result in an electrical short. An electrical short within the EGR valve could lead to a Malfunction Indicator lamp (MIL) illumination (P04…
HYUNDAI
The exhaust gas recirculation (EGR) valve assembly in certain vehicles may contain a sensor that was contaminated with solder flux during manufacturing, which could potentially result in an electrical short. An electrical short within the EGR valve could lead to a Malfunction Indicator lamp (MIL) illumination (P0405, P0642, P065…
Check vehicle applicability
36A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.