Cadillac P1639: 5-Volt Reference 2 Circuit Malfunction
Is your scanner showing Cadillac P1639?
No worries. We'll show you what it means and how to deal with it.
Cadillac P1639: 5-Volt Reference 2 Circuit Malfunction
OVERVIEWWhat Does The Cadillac P1639 Code Mean?
Key on or engine running; and the PCM detected that the voltage range of the 5v VREF 2 circuit was out of tolerance for 10 seconds during the CCM continuous test. The 5v VREF 2 circuit connects to the A/C Pressure and Fuel Tank Pressure (FTP) sensor circuit.
What Are The Potential Causes Of The Cadillac P1639 Code?
- ACP sensor VREF or FTP sensor VREF circuit is open, shorted to ground or to power
- A/C refrigerant pressure or the Fuel Tank pressure sensor is damaged or has failed
- PCM has failed
Recommended Parts
Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:
Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!
