Is a certificate of probable cause required to challenge a motion to withdraw a guilty or no contest plea?

A certificate of probable cause is required to challenge the denial of a motion to withdraw a guilty or no contest plea, but is not required to raise sentencing issues that do not pertain to an integral part of the plea agreement. ( 1237.5; People v. Johnson (2009) 47 Cal.4th 668, 678, 679.) Although the trial court "granted" appellant's request for a certificate of probable cause, it did so "only as to the sentence imposed." In light of this limitation, which rendered the order a nullity given that no certificate of probable cause is required to address most sentencing issues, the court's purported granting of the certificate arguably is not sufficient to authorize appellate review of the motion to withdraw the plea.