P0643

Sensor Reference Voltage "A" Circuit High

DTC P0643, sometimes indicated as P064300 is an OBD diagnostic trouble code indicating a generic fault with the vehicle powertrain (i.e. engine and gearbox). This code identifies an error with the causing sensor reference voltage "a" circuit high.

The most common cause of this code is a short circuit or open circuit in the wiring or connector to the sensor. Other causes can include a bad sensor, a wiring harness that is chafed or broken, or a bad power or ground connection.

P0643: Sensor Reference Voltage A Circuit High
P0643: Sensor Reference Voltage "A" Circuit High
P0643: Sensor A Reference Voltage Circuit High
P0643: Sensor reference voltage A – circuit high
P0643 00: Sensor reference voltage A - circuit high

DTC Trouble Code Search

Bulletins

Bulletins are notices put out by manufacturers in conjunction with the NHTSA to notify the public of manufacturing issues or changes.

20131 - ELECTRICAL SYSTEM:WIRING:FUSES AND CIRCUIT BREAKERS
FORD: 2008 f-super duty 6.4l diesel - vref codes P1335, P0193, P0642, P0643, or P0652. *nj

Consumer Complaints for this DTC

2005 NISSAN XTERRA with 54000.0 miles

Error code on 2005 Nissan Xterra - P0643 has shown up on many models with this engine. Noted on an emission inspection for annual tx inspection.
ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL,

1962 COPCO COPCO with 91267.0 miles

Nissan xterra 2006, both front cats have failed. Dealer said due to ethanol a common problem, cost around $2300. Found cats and a mechanic for $1200. After 3 weeks check engine light returned. I am now getting a P0643. Dealer passport nissan quoted around $700 to fix plus another $350 for belt replacement. None of the other recalls am eligible for due to being out of warranty. Also had to replace front and rear u-joints within a year of each.
EQUIPMENT:MECHANICAL, FUEL SYSTEM, GASOLINE STEERING